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/*
 * Copyright (C) 2007 The Guava Authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.common.collect;

import static com.google.common.base.Preconditions.checkArgument;
import static com.google.common.base.Preconditions.checkNotNull;
import static com.google.common.base.Predicates.compose;
import static com.google.common.collect.CollectPreconditions.checkEntryNotNull;
import static com.google.common.collect.CollectPreconditions.checkNonnegative;

import com.google.common.annotations.Beta;
import com.google.common.annotations.GwtCompatible;
import com.google.common.annotations.GwtIncompatible;
import com.google.common.base.Converter;
import com.google.common.base.Equivalence;
import com.google.common.base.Function;
import com.google.common.base.Objects;
import com.google.common.base.Preconditions;
import com.google.common.base.Predicate;
import com.google.common.base.Predicates;
import com.google.common.collect.MapDifference.ValueDifference;
import com.google.common.primitives.Ints;
import com.google.errorprone.annotations.CanIgnoreReturnValue;
import com.google.j2objc.annotations.RetainedWith;
import com.google.j2objc.annotations.Weak;
import com.google.j2objc.annotations.WeakOuter;
import java.io.Serializable;
import java.util.AbstractCollection;
import java.util.AbstractMap;
import java.util.Collection;
import java.util.Collections;
import java.util.Comparator;
import java.util.EnumMap;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.IdentityHashMap;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.Map.Entry;
import java.util.NavigableMap;
import java.util.NavigableSet;
import java.util.Properties;
import java.util.Set;
import java.util.SortedMap;
import java.util.SortedSet;
import java.util.TreeMap;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import org.checkerframework.checker.nullness.compatqual.NullableDecl;

/**
 * Static utility methods pertaining to {@link Map} instances (including instances of {@link
 * SortedMap}, {@link BiMap}, etc.). Also see this class's counterparts {@link Lists}, {@link Sets}
 * and {@link Queues}.
 *
 * 

See the Guava User Guide article on {@code Maps}. * * @author Kevin Bourrillion * @author Mike Bostock * @author Isaac Shum * @author Louis Wasserman * @since 2.0 */ @GwtCompatible(emulated = true) public final class Maps { private Maps() {} private enum EntryFunction implements Function, Object> { KEY { @Override @NullableDecl public Object apply(Entry entry) { return entry.getKey(); } }, VALUE { @Override @NullableDecl public Object apply(Entry entry) { return entry.getValue(); } }; } @SuppressWarnings("unchecked") static Function, K> keyFunction() { return (Function) EntryFunction.KEY; } @SuppressWarnings("unchecked") static Function, V> valueFunction() { return (Function) EntryFunction.VALUE; } static Iterator keyIterator(Iterator> entryIterator) { return new TransformedIterator, K>(entryIterator) { @Override K transform(Entry entry) { return entry.getKey(); } }; } static Iterator valueIterator(Iterator> entryIterator) { return new TransformedIterator, V>(entryIterator) { @Override V transform(Entry entry) { return entry.getValue(); } }; } /** * Returns an immutable map instance containing the given entries. Internally, the returned map * will be backed by an {@link EnumMap}. * *

The iteration order of the returned map follows the enum's iteration order, not the order in * which the elements appear in the given map. * * @param map the map to make an immutable copy of * @return an immutable map containing those entries * @since 14.0 */ @GwtCompatible(serializable = true) public static , V> ImmutableMap immutableEnumMap( Map map) { if (map instanceof ImmutableEnumMap) { @SuppressWarnings("unchecked") // safe covariant cast ImmutableEnumMap result = (ImmutableEnumMap) map; return result; } Iterator> entryItr = map.entrySet().iterator(); if (!entryItr.hasNext()) { return ImmutableMap.of(); } Entry entry1 = entryItr.next(); K key1 = entry1.getKey(); V value1 = entry1.getValue(); checkEntryNotNull(key1, value1); Class clazz = key1.getDeclaringClass(); EnumMap enumMap = new EnumMap<>(clazz); enumMap.put(key1, value1); while (entryItr.hasNext()) { Entry entry = entryItr.next(); K key = entry.getKey(); V value = entry.getValue(); checkEntryNotNull(key, value); enumMap.put(key, value); } return ImmutableEnumMap.asImmutable(enumMap); } /** * Creates a mutable, empty {@code HashMap} instance. * *

Note: if mutability is not required, use {@link ImmutableMap#of()} instead. * *

Note: if {@code K} is an {@code enum} type, use {@link #newEnumMap} instead. * *

Note for Java 7 and later: this method is now unnecessary and should be treated as * deprecated. Instead, use the {@code HashMap} constructor directly, taking advantage of the new * "diamond" syntax. * * @return a new, empty {@code HashMap} */ public static HashMap newHashMap() { return new HashMap<>(); } /** * Creates a mutable {@code HashMap} instance with the same mappings as the specified map. * *

Note: if mutability is not required, use {@link ImmutableMap#copyOf(Map)} instead. * *

Note: if {@code K} is an {@link Enum} type, use {@link #newEnumMap} instead. * *

Note for Java 7 and later: this method is now unnecessary and should be treated as * deprecated. Instead, use the {@code HashMap} constructor directly, taking advantage of the new * "diamond" syntax. * * @param map the mappings to be placed in the new map * @return a new {@code HashMap} initialized with the mappings from {@code map} */ public static HashMap newHashMap(Map map) { return new HashMap<>(map); } /** * Creates a {@code HashMap} instance, with a high enough "initial capacity" that it should * hold {@code expectedSize} elements without growth. This behavior cannot be broadly guaranteed, * but it is observed to be true for OpenJDK 1.7. It also can't be guaranteed that the method * isn't inadvertently oversizing the returned map. * * @param expectedSize the number of entries you expect to add to the returned map * @return a new, empty {@code HashMap} with enough capacity to hold {@code expectedSize} entries * without resizing * @throws IllegalArgumentException if {@code expectedSize} is negative */ public static HashMap newHashMapWithExpectedSize(int expectedSize) { return new HashMap<>(capacity(expectedSize)); } /** * Returns a capacity that is sufficient to keep the map from being resized as long as it grows no * larger than expectedSize and the load factor is ≥ its default (0.75). */ static int capacity(int expectedSize) { if (expectedSize < 3) { checkNonnegative(expectedSize, "expectedSize"); return expectedSize + 1; } if (expectedSize < Ints.MAX_POWER_OF_TWO) { // This is the calculation used in JDK8 to resize when a putAll // happens; it seems to be the most conservative calculation we // can make. 0.75 is the default load factor. return (int) ((float) expectedSize / 0.75F + 1.0F); } return Integer.MAX_VALUE; // any large value } /** * Creates a mutable, empty, insertion-ordered {@code LinkedHashMap} instance. * *

Note: if mutability is not required, use {@link ImmutableMap#of()} instead. * *

Note for Java 7 and later: this method is now unnecessary and should be treated as * deprecated. Instead, use the {@code LinkedHashMap} constructor directly, taking advantage of * the new "diamond" syntax. * * @return a new, empty {@code LinkedHashMap} */ public static LinkedHashMap newLinkedHashMap() { return new LinkedHashMap<>(); } /** * Creates a mutable, insertion-ordered {@code LinkedHashMap} instance with the same * mappings as the specified map. * *

Note: if mutability is not required, use {@link ImmutableMap#copyOf(Map)} instead. * *

Note for Java 7 and later: this method is now unnecessary and should be treated as * deprecated. Instead, use the {@code LinkedHashMap} constructor directly, taking advantage of * the new "diamond" syntax. * * @param map the mappings to be placed in the new map * @return a new, {@code LinkedHashMap} initialized with the mappings from {@code map} */ public static LinkedHashMap newLinkedHashMap(Map map) { return new LinkedHashMap<>(map); } /** * Creates a {@code LinkedHashMap} instance, with a high enough "initial capacity" that it * should hold {@code expectedSize} elements without growth. This behavior cannot be * broadly guaranteed, but it is observed to be true for OpenJDK 1.7. It also can't be guaranteed * that the method isn't inadvertently oversizing the returned map. * * @param expectedSize the number of entries you expect to add to the returned map * @return a new, empty {@code LinkedHashMap} with enough capacity to hold {@code expectedSize} * entries without resizing * @throws IllegalArgumentException if {@code expectedSize} is negative * @since 19.0 */ public static LinkedHashMap newLinkedHashMapWithExpectedSize(int expectedSize) { return new LinkedHashMap<>(capacity(expectedSize)); } /** * Creates a new empty {@link ConcurrentHashMap} instance. * * @since 3.0 */ public static ConcurrentMap newConcurrentMap() { return new ConcurrentHashMap<>(); } /** * Creates a mutable, empty {@code TreeMap} instance using the natural ordering of its * elements. * *

Note: if mutability is not required, use {@link ImmutableSortedMap#of()} instead. * *

Note for Java 7 and later: this method is now unnecessary and should be treated as * deprecated. Instead, use the {@code TreeMap} constructor directly, taking advantage of the new * "diamond" syntax. * * @return a new, empty {@code TreeMap} */ public static TreeMap newTreeMap() { return new TreeMap<>(); } /** * Creates a mutable {@code TreeMap} instance with the same mappings as the specified map * and using the same ordering as the specified map. * *

Note: if mutability is not required, use {@link * ImmutableSortedMap#copyOfSorted(SortedMap)} instead. * *

Note for Java 7 and later: this method is now unnecessary and should be treated as * deprecated. Instead, use the {@code TreeMap} constructor directly, taking advantage of the new * "diamond" syntax. * * @param map the sorted map whose mappings are to be placed in the new map and whose comparator * is to be used to sort the new map * @return a new {@code TreeMap} initialized with the mappings from {@code map} and using the * comparator of {@code map} */ public static TreeMap newTreeMap(SortedMap map) { return new TreeMap<>(map); } /** * Creates a mutable, empty {@code TreeMap} instance using the given comparator. * *

Note: if mutability is not required, use {@code * ImmutableSortedMap.orderedBy(comparator).build()} instead. * *

Note for Java 7 and later: this method is now unnecessary and should be treated as * deprecated. Instead, use the {@code TreeMap} constructor directly, taking advantage of the new * "diamond" syntax. * * @param comparator the comparator to sort the keys with * @return a new, empty {@code TreeMap} */ public static TreeMap newTreeMap( @NullableDecl Comparator comparator) { // Ideally, the extra type parameter "C" shouldn't be necessary. It is a // work-around of a compiler type inference quirk that prevents the // following code from being compiled: // Comparator> comparator = null; // Map, String> map = newTreeMap(comparator); return new TreeMap<>(comparator); } /** * Creates an {@code EnumMap} instance. * * @param type the key type for this map * @return a new, empty {@code EnumMap} */ public static , V> EnumMap newEnumMap(Class type) { return new EnumMap<>(checkNotNull(type)); } /** * Creates an {@code EnumMap} with the same mappings as the specified map. * *

Note for Java 7 and later: this method is now unnecessary and should be treated as * deprecated. Instead, use the {@code EnumMap} constructor directly, taking advantage of the new * "diamond" syntax. * * @param map the map from which to initialize this {@code EnumMap} * @return a new {@code EnumMap} initialized with the mappings from {@code map} * @throws IllegalArgumentException if {@code m} is not an {@code EnumMap} instance and contains * no mappings */ public static , V> EnumMap newEnumMap(Map map) { return new EnumMap<>(map); } /** * Creates an {@code IdentityHashMap} instance. * *

Note for Java 7 and later: this method is now unnecessary and should be treated as * deprecated. Instead, use the {@code IdentityHashMap} constructor directly, taking advantage of * the new "diamond" syntax. * * @return a new, empty {@code IdentityHashMap} */ public static IdentityHashMap newIdentityHashMap() { return new IdentityHashMap<>(); } /** * Computes the difference between two maps. This difference is an immutable snapshot of the state * of the maps at the time this method is called. It will never change, even if the maps change at * a later time. * *

Since this method uses {@code HashMap} instances internally, the keys of the supplied maps * must be well-behaved with respect to {@link Object#equals} and {@link Object#hashCode}. * *

Note:If you only need to know whether two maps have the same mappings, call {@code * left.equals(right)} instead of this method. * * @param left the map to treat as the "left" map for purposes of comparison * @param right the map to treat as the "right" map for purposes of comparison * @return the difference between the two maps */ @SuppressWarnings("unchecked") public static MapDifference difference( Map left, Map right) { if (left instanceof SortedMap) { SortedMap sortedLeft = (SortedMap) left; return difference(sortedLeft, right); } return difference(left, right, Equivalence.equals()); } /** * Computes the difference between two maps. This difference is an immutable snapshot of the state * of the maps at the time this method is called. It will never change, even if the maps change at * a later time. * *

Since this method uses {@code HashMap} instances internally, the keys of the supplied maps * must be well-behaved with respect to {@link Object#equals} and {@link Object#hashCode}. * * @param left the map to treat as the "left" map for purposes of comparison * @param right the map to treat as the "right" map for purposes of comparison * @param valueEquivalence the equivalence relationship to use to compare values * @return the difference between the two maps * @since 10.0 */ public static MapDifference difference( Map left, Map right, Equivalence valueEquivalence) { Preconditions.checkNotNull(valueEquivalence); Map onlyOnLeft = newLinkedHashMap(); Map onlyOnRight = new LinkedHashMap<>(right); // will whittle it down Map onBoth = newLinkedHashMap(); Map> differences = newLinkedHashMap(); doDifference(left, right, valueEquivalence, onlyOnLeft, onlyOnRight, onBoth, differences); return new MapDifferenceImpl<>(onlyOnLeft, onlyOnRight, onBoth, differences); } /** * Computes the difference between two sorted maps, using the comparator of the left map, or * {@code Ordering.natural()} if the left map uses the natural ordering of its elements. This * difference is an immutable snapshot of the state of the maps at the time this method is called. * It will never change, even if the maps change at a later time. * *

Since this method uses {@code TreeMap} instances internally, the keys of the right map must * all compare as distinct according to the comparator of the left map. * *

Note:If you only need to know whether two sorted maps have the same mappings, call * {@code left.equals(right)} instead of this method. * * @param left the map to treat as the "left" map for purposes of comparison * @param right the map to treat as the "right" map for purposes of comparison * @return the difference between the two maps * @since 11.0 */ public static SortedMapDifference difference( SortedMap left, Map right) { checkNotNull(left); checkNotNull(right); Comparator comparator = orNaturalOrder(left.comparator()); SortedMap onlyOnLeft = Maps.newTreeMap(comparator); SortedMap onlyOnRight = Maps.newTreeMap(comparator); onlyOnRight.putAll(right); // will whittle it down SortedMap onBoth = Maps.newTreeMap(comparator); SortedMap> differences = Maps.newTreeMap(comparator); doDifference(left, right, Equivalence.equals(), onlyOnLeft, onlyOnRight, onBoth, differences); return new SortedMapDifferenceImpl<>(onlyOnLeft, onlyOnRight, onBoth, differences); } private static void doDifference( Map left, Map right, Equivalence valueEquivalence, Map onlyOnLeft, Map onlyOnRight, Map onBoth, Map> differences) { for (Entry entry : left.entrySet()) { K leftKey = entry.getKey(); V leftValue = entry.getValue(); if (right.containsKey(leftKey)) { V rightValue = onlyOnRight.remove(leftKey); if (valueEquivalence.equivalent(leftValue, rightValue)) { onBoth.put(leftKey, leftValue); } else { differences.put(leftKey, ValueDifferenceImpl.create(leftValue, rightValue)); } } else { onlyOnLeft.put(leftKey, leftValue); } } } private static Map unmodifiableMap(Map map) { if (map instanceof SortedMap) { return Collections.unmodifiableSortedMap((SortedMap) map); } else { return Collections.unmodifiableMap(map); } } static class MapDifferenceImpl implements MapDifference { final Map onlyOnLeft; final Map onlyOnRight; final Map onBoth; final Map> differences; MapDifferenceImpl( Map onlyOnLeft, Map onlyOnRight, Map onBoth, Map> differences) { this.onlyOnLeft = unmodifiableMap(onlyOnLeft); this.onlyOnRight = unmodifiableMap(onlyOnRight); this.onBoth = unmodifiableMap(onBoth); this.differences = unmodifiableMap(differences); } @Override public boolean areEqual() { return onlyOnLeft.isEmpty() && onlyOnRight.isEmpty() && differences.isEmpty(); } @Override public Map entriesOnlyOnLeft() { return onlyOnLeft; } @Override public Map entriesOnlyOnRight() { return onlyOnRight; } @Override public Map entriesInCommon() { return onBoth; } @Override public Map> entriesDiffering() { return differences; } @Override public boolean equals(Object object) { if (object == this) { return true; } if (object instanceof MapDifference) { MapDifference other = (MapDifference) object; return entriesOnlyOnLeft().equals(other.entriesOnlyOnLeft()) && entriesOnlyOnRight().equals(other.entriesOnlyOnRight()) && entriesInCommon().equals(other.entriesInCommon()) && entriesDiffering().equals(other.entriesDiffering()); } return false; } @Override public int hashCode() { return Objects.hashCode( entriesOnlyOnLeft(), entriesOnlyOnRight(), entriesInCommon(), entriesDiffering()); } @Override public String toString() { if (areEqual()) { return "equal"; } StringBuilder result = new StringBuilder("not equal"); if (!onlyOnLeft.isEmpty()) { result.append(": only on left=").append(onlyOnLeft); } if (!onlyOnRight.isEmpty()) { result.append(": only on right=").append(onlyOnRight); } if (!differences.isEmpty()) { result.append(": value differences=").append(differences); } return result.toString(); } } static class ValueDifferenceImpl implements MapDifference.ValueDifference { @NullableDecl private final V left; @NullableDecl private final V right; static ValueDifference create(@NullableDecl V left, @NullableDecl V right) { return new ValueDifferenceImpl(left, right); } private ValueDifferenceImpl(@NullableDecl V left, @NullableDecl V right) { this.left = left; this.right = right; } @Override public V leftValue() { return left; } @Override public V rightValue() { return right; } @Override public boolean equals(@NullableDecl Object object) { if (object instanceof MapDifference.ValueDifference) { MapDifference.ValueDifference that = (MapDifference.ValueDifference) object; return Objects.equal(this.left, that.leftValue()) && Objects.equal(this.right, that.rightValue()); } return false; } @Override public int hashCode() { return Objects.hashCode(left, right); } @Override public String toString() { return "(" + left + ", " + right + ")"; } } static class SortedMapDifferenceImpl extends MapDifferenceImpl implements SortedMapDifference { SortedMapDifferenceImpl( SortedMap onlyOnLeft, SortedMap onlyOnRight, SortedMap onBoth, SortedMap> differences) { super(onlyOnLeft, onlyOnRight, onBoth, differences); } @Override public SortedMap> entriesDiffering() { return (SortedMap>) super.entriesDiffering(); } @Override public SortedMap entriesInCommon() { return (SortedMap) super.entriesInCommon(); } @Override public SortedMap entriesOnlyOnLeft() { return (SortedMap) super.entriesOnlyOnLeft(); } @Override public SortedMap entriesOnlyOnRight() { return (SortedMap) super.entriesOnlyOnRight(); } } /** * Returns the specified comparator if not null; otherwise returns {@code Ordering.natural()}. * This method is an abomination of generics; the only purpose of this method is to contain the * ugly type-casting in one place. */ @SuppressWarnings("unchecked") static Comparator orNaturalOrder(@NullableDecl Comparator comparator) { if (comparator != null) { // can't use ? : because of javac bug 5080917 return comparator; } return (Comparator) Ordering.natural(); } /** * Returns a live {@link Map} view whose keys are the contents of {@code set} and whose values are * computed on demand using {@code function}. To get an immutable copy instead, use {@link * #toMap(Iterable, Function)}. * *

Specifically, for each {@code k} in the backing set, the returned map has an entry mapping * {@code k} to {@code function.apply(k)}. The {@code keySet}, {@code values}, and {@code * entrySet} views of the returned map iterate in the same order as the backing set. * *

Modifications to the backing set are read through to the returned map. The returned map * supports removal operations if the backing set does. Removal operations write through to the * backing set. The returned map does not support put operations. * *

Warning: If the function rejects {@code null}, caution is required to make sure the * set does not contain {@code null}, because the view cannot stop {@code null} from being added * to the set. * *

Warning: This method assumes that for any instance {@code k} of key type {@code K}, * {@code k.equals(k2)} implies that {@code k2} is also of type {@code K}. Using a key type for * which this may not hold, such as {@code ArrayList}, may risk a {@code ClassCastException} when * calling methods on the resulting map view. * * @since 14.0 */ public static Map asMap(Set set, Function function) { return new AsMapView<>(set, function); } /** * Returns a view of the sorted set as a map, mapping keys from the set according to the specified * function. * *

Specifically, for each {@code k} in the backing set, the returned map has an entry mapping * {@code k} to {@code function.apply(k)}. The {@code keySet}, {@code values}, and {@code * entrySet} views of the returned map iterate in the same order as the backing set. * *

Modifications to the backing set are read through to the returned map. The returned map * supports removal operations if the backing set does. Removal operations write through to the * backing set. The returned map does not support put operations. * *

Warning: If the function rejects {@code null}, caution is required to make sure the * set does not contain {@code null}, because the view cannot stop {@code null} from being added * to the set. * *

Warning: This method assumes that for any instance {@code k} of key type {@code K}, * {@code k.equals(k2)} implies that {@code k2} is also of type {@code K}. Using a key type for * which this may not hold, such as {@code ArrayList}, may risk a {@code ClassCastException} when * calling methods on the resulting map view. * * @since 14.0 */ public static SortedMap asMap(SortedSet set, Function function) { return new SortedAsMapView<>(set, function); } /** * Returns a view of the navigable set as a map, mapping keys from the set according to the * specified function. * *

Specifically, for each {@code k} in the backing set, the returned map has an entry mapping * {@code k} to {@code function.apply(k)}. The {@code keySet}, {@code values}, and {@code * entrySet} views of the returned map iterate in the same order as the backing set. * *

Modifications to the backing set are read through to the returned map. The returned map * supports removal operations if the backing set does. Removal operations write through to the * backing set. The returned map does not support put operations. * *

Warning: If the function rejects {@code null}, caution is required to make sure the * set does not contain {@code null}, because the view cannot stop {@code null} from being added * to the set. * *

Warning: This method assumes that for any instance {@code k} of key type {@code K}, * {@code k.equals(k2)} implies that {@code k2} is also of type {@code K}. Using a key type for * which this may not hold, such as {@code ArrayList}, may risk a {@code ClassCastException} when * calling methods on the resulting map view. * * @since 14.0 */ @GwtIncompatible // NavigableMap public static NavigableMap asMap( NavigableSet set, Function function) { return new NavigableAsMapView<>(set, function); } private static class AsMapView extends ViewCachingAbstractMap { private final Set set; final Function function; Set backingSet() { return set; } AsMapView(Set set, Function function) { this.set = checkNotNull(set); this.function = checkNotNull(function); } @Override public Set createKeySet() { return removeOnlySet(backingSet()); } @Override Collection createValues() { return Collections2.transform(set, function); } @Override public int size() { return backingSet().size(); } @Override public boolean containsKey(@NullableDecl Object key) { return backingSet().contains(key); } @Override public V get(@NullableDecl Object key) { if (Collections2.safeContains(backingSet(), key)) { @SuppressWarnings("unchecked") // unsafe, but Javadoc warns about it K k = (K) key; return function.apply(k); } else { return null; } } @Override public V remove(@NullableDecl Object key) { if (backingSet().remove(key)) { @SuppressWarnings("unchecked") // unsafe, but Javadoc warns about it K k = (K) key; return function.apply(k); } else { return null; } } @Override public void clear() { backingSet().clear(); } @Override protected Set> createEntrySet() { @WeakOuter class EntrySetImpl extends EntrySet { @Override Map map() { return AsMapView.this; } @Override public Iterator> iterator() { return asMapEntryIterator(backingSet(), function); } } return new EntrySetImpl(); } } static Iterator> asMapEntryIterator( Set set, final Function function) { return new TransformedIterator>(set.iterator()) { @Override Entry transform(final K key) { return immutableEntry(key, function.apply(key)); } }; } private static class SortedAsMapView extends AsMapView implements SortedMap { SortedAsMapView(SortedSet set, Function function) { super(set, function); } @Override SortedSet backingSet() { return (SortedSet) super.backingSet(); } @Override public Comparator comparator() { return backingSet().comparator(); } @Override public Set keySet() { return removeOnlySortedSet(backingSet()); } @Override public SortedMap subMap(K fromKey, K toKey) { return asMap(backingSet().subSet(fromKey, toKey), function); } @Override public SortedMap headMap(K toKey) { return asMap(backingSet().headSet(toKey), function); } @Override public SortedMap tailMap(K fromKey) { return asMap(backingSet().tailSet(fromKey), function); } @Override public K firstKey() { return backingSet().first(); } @Override public K lastKey() { return backingSet().last(); } } @GwtIncompatible // NavigableMap private static final class NavigableAsMapView extends AbstractNavigableMap { /* * Using AbstractNavigableMap is simpler than extending SortedAsMapView and rewriting all the * NavigableMap methods. */ private final NavigableSet set; private final Function function; NavigableAsMapView(NavigableSet ks, Function vFunction) { this.set = checkNotNull(ks); this.function = checkNotNull(vFunction); } @Override public NavigableMap subMap( K fromKey, boolean fromInclusive, K toKey, boolean toInclusive) { return asMap(set.subSet(fromKey, fromInclusive, toKey, toInclusive), function); } @Override public NavigableMap headMap(K toKey, boolean inclusive) { return asMap(set.headSet(toKey, inclusive), function); } @Override public NavigableMap tailMap(K fromKey, boolean inclusive) { return asMap(set.tailSet(fromKey, inclusive), function); } @Override public Comparator comparator() { return set.comparator(); } @Override @NullableDecl public V get(@NullableDecl Object key) { if (Collections2.safeContains(set, key)) { @SuppressWarnings("unchecked") // unsafe, but Javadoc warns about it K k = (K) key; return function.apply(k); } else { return null; } } @Override public void clear() { set.clear(); } @Override Iterator> entryIterator() { return asMapEntryIterator(set, function); } @Override Iterator> descendingEntryIterator() { return descendingMap().entrySet().iterator(); } @Override public NavigableSet navigableKeySet() { return removeOnlyNavigableSet(set); } @Override public int size() { return set.size(); } @Override public NavigableMap descendingMap() { return asMap(set.descendingSet(), function); } } private static Set removeOnlySet(final Set set) { return new ForwardingSet() { @Override protected Set delegate() { return set; } @Override public boolean add(E element) { throw new UnsupportedOperationException(); } @Override public boolean addAll(Collection es) { throw new UnsupportedOperationException(); } }; } private static SortedSet removeOnlySortedSet(final SortedSet set) { return new ForwardingSortedSet() { @Override protected SortedSet delegate() { return set; } @Override public boolean add(E element) { throw new UnsupportedOperationException(); } @Override public boolean addAll(Collection es) { throw new UnsupportedOperationException(); } @Override public SortedSet headSet(E toElement) { return removeOnlySortedSet(super.headSet(toElement)); } @Override public SortedSet subSet(E fromElement, E toElement) { return removeOnlySortedSet(super.subSet(fromElement, toElement)); } @Override public SortedSet tailSet(E fromElement) { return removeOnlySortedSet(super.tailSet(fromElement)); } }; } @GwtIncompatible // NavigableSet private static NavigableSet removeOnlyNavigableSet(final NavigableSet set) { return new ForwardingNavigableSet() { @Override protected NavigableSet delegate() { return set; } @Override public boolean add(E element) { throw new UnsupportedOperationException(); } @Override public boolean addAll(Collection es) { throw new UnsupportedOperationException(); } @Override public SortedSet headSet(E toElement) { return removeOnlySortedSet(super.headSet(toElement)); } @Override public NavigableSet headSet(E toElement, boolean inclusive) { return removeOnlyNavigableSet(super.headSet(toElement, inclusive)); } @Override public SortedSet subSet(E fromElement, E toElement) { return removeOnlySortedSet(super.subSet(fromElement, toElement)); } @Override public NavigableSet subSet( E fromElement, boolean fromInclusive, E toElement, boolean toInclusive) { return removeOnlyNavigableSet( super.subSet(fromElement, fromInclusive, toElement, toInclusive)); } @Override public SortedSet tailSet(E fromElement) { return removeOnlySortedSet(super.tailSet(fromElement)); } @Override public NavigableSet tailSet(E fromElement, boolean inclusive) { return removeOnlyNavigableSet(super.tailSet(fromElement, inclusive)); } @Override public NavigableSet descendingSet() { return removeOnlyNavigableSet(super.descendingSet()); } }; } /** * Returns an immutable map whose keys are the distinct elements of {@code keys} and whose value * for each key was computed by {@code valueFunction}. The map's iteration order is the order of * the first appearance of each key in {@code keys}. * *

When there are multiple instances of a key in {@code keys}, it is unspecified whether {@code * valueFunction} will be applied to more than one instance of that key and, if it is, which * result will be mapped to that key in the returned map. * *

If {@code keys} is a {@link Set}, a live view can be obtained instead of a copy using {@link * Maps#asMap(Set, Function)}. * * @throws NullPointerException if any element of {@code keys} is {@code null}, or if {@code * valueFunction} produces {@code null} for any key * @since 14.0 */ public static ImmutableMap toMap( Iterable keys, Function valueFunction) { return toMap(keys.iterator(), valueFunction); } /** * Returns an immutable map whose keys are the distinct elements of {@code keys} and whose value * for each key was computed by {@code valueFunction}. The map's iteration order is the order of * the first appearance of each key in {@code keys}. * *

When there are multiple instances of a key in {@code keys}, it is unspecified whether {@code * valueFunction} will be applied to more than one instance of that key and, if it is, which * result will be mapped to that key in the returned map. * * @throws NullPointerException if any element of {@code keys} is {@code null}, or if {@code * valueFunction} produces {@code null} for any key * @since 14.0 */ public static ImmutableMap toMap( Iterator keys, Function valueFunction) { checkNotNull(valueFunction); // Using LHM instead of a builder so as not to fail on duplicate keys Map builder = newLinkedHashMap(); while (keys.hasNext()) { K key = keys.next(); builder.put(key, valueFunction.apply(key)); } return ImmutableMap.copyOf(builder); } /** * Returns a map with the given {@code values}, indexed by keys derived from those values. In * other words, each input value produces an entry in the map whose key is the result of applying * {@code keyFunction} to that value. These entries appear in the same order as the input values. * Example usage: * *

{@code
   * Color red = new Color("red", 255, 0, 0);
   * ...
   * ImmutableSet allColors = ImmutableSet.of(red, green, blue);
   *
   * Map colorForName =
   *     uniqueIndex(allColors, toStringFunction());
   * assertThat(colorForName).containsEntry("red", red);
   * }
* *

If your index may associate multiple values with each key, use {@link * Multimaps#index(Iterable, Function) Multimaps.index}. * * @param values the values to use when constructing the {@code Map} * @param keyFunction the function used to produce the key for each value * @return a map mapping the result of evaluating the function {@code keyFunction} on each value * in the input collection to that value * @throws IllegalArgumentException if {@code keyFunction} produces the same key for more than one * value in the input collection * @throws NullPointerException if any element of {@code values} is {@code null}, or if {@code * keyFunction} produces {@code null} for any value */ @CanIgnoreReturnValue public static ImmutableMap uniqueIndex( Iterable values, Function keyFunction) { // TODO(lowasser): consider presizing the builder if values is a Collection return uniqueIndex(values.iterator(), keyFunction); } /** * Returns a map with the given {@code values}, indexed by keys derived from those values. In * other words, each input value produces an entry in the map whose key is the result of applying * {@code keyFunction} to that value. These entries appear in the same order as the input values. * Example usage: * *

{@code
   * Color red = new Color("red", 255, 0, 0);
   * ...
   * Iterator allColors = ImmutableSet.of(red, green, blue).iterator();
   *
   * Map colorForName =
   *     uniqueIndex(allColors, toStringFunction());
   * assertThat(colorForName).containsEntry("red", red);
   * }
* *

If your index may associate multiple values with each key, use {@link * Multimaps#index(Iterator, Function) Multimaps.index}. * * @param values the values to use when constructing the {@code Map} * @param keyFunction the function used to produce the key for each value * @return a map mapping the result of evaluating the function {@code keyFunction} on each value * in the input collection to that value * @throws IllegalArgumentException if {@code keyFunction} produces the same key for more than one * value in the input collection * @throws NullPointerException if any element of {@code values} is {@code null}, or if {@code * keyFunction} produces {@code null} for any value * @since 10.0 */ @CanIgnoreReturnValue public static ImmutableMap uniqueIndex( Iterator values, Function keyFunction) { checkNotNull(keyFunction); ImmutableMap.Builder builder = ImmutableMap.builder(); while (values.hasNext()) { V value = values.next(); builder.put(keyFunction.apply(value), value); } try { return builder.build(); } catch (IllegalArgumentException duplicateKeys) { throw new IllegalArgumentException( duplicateKeys.getMessage() + ". To index multiple values under a key, use Multimaps.index."); } } /** * Creates an {@code ImmutableMap} from a {@code Properties} instance. Properties * normally derive from {@code Map}, but they typically contain strings, which is * awkward. This method lets you get a plain-old-{@code Map} out of a {@code Properties}. * * @param properties a {@code Properties} object to be converted * @return an immutable map containing all the entries in {@code properties} * @throws ClassCastException if any key in {@code Properties} is not a {@code String} * @throws NullPointerException if any key or value in {@code Properties} is null */ @GwtIncompatible // java.util.Properties public static ImmutableMap fromProperties(Properties properties) { ImmutableMap.Builder builder = ImmutableMap.builder(); for (Enumeration e = properties.propertyNames(); e.hasMoreElements(); ) { String key = (String) e.nextElement(); builder.put(key, properties.getProperty(key)); } return builder.build(); } /** * Returns an immutable map entry with the specified key and value. The {@link Entry#setValue} * operation throws an {@link UnsupportedOperationException}. * *

The returned entry is serializable. * *

Java 9 users: consider using {@code java.util.Map.entry(key, value)} if the key and * value are non-null and the entry does not need to be serializable. * * @param key the key to be associated with the returned entry * @param value the value to be associated with the returned entry */ @GwtCompatible(serializable = true) public static Entry immutableEntry(@NullableDecl K key, @NullableDecl V value) { return new ImmutableEntry<>(key, value); } /** * Returns an unmodifiable view of the specified set of entries. The {@link Entry#setValue} * operation throws an {@link UnsupportedOperationException}, as do any operations that would * modify the returned set. * * @param entrySet the entries for which to return an unmodifiable view * @return an unmodifiable view of the entries */ static Set> unmodifiableEntrySet(Set> entrySet) { return new UnmodifiableEntrySet<>(Collections.unmodifiableSet(entrySet)); } /** * Returns an unmodifiable view of the specified map entry. The {@link Entry#setValue} operation * throws an {@link UnsupportedOperationException}. This also has the side-effect of redefining * {@code equals} to comply with the Entry contract, to avoid a possible nefarious implementation * of equals. * * @param entry the entry for which to return an unmodifiable view * @return an unmodifiable view of the entry */ static Entry unmodifiableEntry(final Entry entry) { checkNotNull(entry); return new AbstractMapEntry() { @Override public K getKey() { return entry.getKey(); } @Override public V getValue() { return entry.getValue(); } }; } static UnmodifiableIterator> unmodifiableEntryIterator( final Iterator> entryIterator) { return new UnmodifiableIterator>() { @Override public boolean hasNext() { return entryIterator.hasNext(); } @Override public Entry next() { return unmodifiableEntry(entryIterator.next()); } }; } /** @see Multimaps#unmodifiableEntries */ static class UnmodifiableEntries extends ForwardingCollection> { private final Collection> entries; UnmodifiableEntries(Collection> entries) { this.entries = entries; } @Override protected Collection> delegate() { return entries; } @Override public Iterator> iterator() { return unmodifiableEntryIterator(entries.iterator()); } // See java.util.Collections.UnmodifiableEntrySet for details on attacks. @Override public Object[] toArray() { return standardToArray(); } @Override public T[] toArray(T[] array) { return standardToArray(array); } } /** @see Maps#unmodifiableEntrySet(Set) */ static class UnmodifiableEntrySet extends UnmodifiableEntries implements Set> { UnmodifiableEntrySet(Set> entries) { super(entries); } // See java.util.Collections.UnmodifiableEntrySet for details on attacks. @Override public boolean equals(@NullableDecl Object object) { return Sets.equalsImpl(this, object); } @Override public int hashCode() { return Sets.hashCodeImpl(this); } } /** * Returns a {@link Converter} that converts values using {@link BiMap#get bimap.get()}, and whose * inverse view converts values using {@link BiMap#inverse bimap.inverse()}{@code .get()}. * *

To use a plain {@link Map} as a {@link Function}, see {@link * com.google.common.base.Functions#forMap(Map)} or {@link * com.google.common.base.Functions#forMap(Map, Object)}. * * @since 16.0 */ public static Converter asConverter(final BiMap bimap) { return new BiMapConverter<>(bimap); } private static final class BiMapConverter extends Converter implements Serializable { private final BiMap bimap; BiMapConverter(BiMap bimap) { this.bimap = checkNotNull(bimap); } @Override protected B doForward(A a) { return convert(bimap, a); } @Override protected A doBackward(B b) { return convert(bimap.inverse(), b); } private static Y convert(BiMap bimap, X input) { Y output = bimap.get(input); checkArgument(output != null, "No non-null mapping present for input: %s", input); return output; } @Override public boolean equals(@NullableDecl Object object) { if (object instanceof BiMapConverter) { BiMapConverter that = (BiMapConverter) object; return this.bimap.equals(that.bimap); } return false; } @Override public int hashCode() { return bimap.hashCode(); } // There's really no good way to implement toString() without printing the entire BiMap, right? @Override public String toString() { return "Maps.asConverter(" + bimap + ")"; } private static final long serialVersionUID = 0L; } /** * Returns a synchronized (thread-safe) bimap backed by the specified bimap. In order to guarantee * serial access, it is critical that all access to the backing bimap is accomplished * through the returned bimap. * *

It is imperative that the user manually synchronize on the returned map when accessing any * of its collection views: * *

{@code
   * BiMap map = Maps.synchronizedBiMap(
   *     HashBiMap.create());
   * ...
   * Set set = map.keySet();  // Needn't be in synchronized block
   * ...
   * synchronized (map) {  // Synchronizing on map, not set!
   *   Iterator it = set.iterator(); // Must be in synchronized block
   *   while (it.hasNext()) {
   *     foo(it.next());
   *   }
   * }
   * }
* *

Failure to follow this advice may result in non-deterministic behavior. * *

The returned bimap will be serializable if the specified bimap is serializable. * * @param bimap the bimap to be wrapped in a synchronized view * @return a synchronized view of the specified bimap */ public static BiMap synchronizedBiMap(BiMap bimap) { return Synchronized.biMap(bimap, null); } /** * Returns an unmodifiable view of the specified bimap. This method allows modules to provide * users with "read-only" access to internal bimaps. Query operations on the returned bimap "read * through" to the specified bimap, and attempts to modify the returned map, whether direct or via * its collection views, result in an {@code UnsupportedOperationException}. * *

The returned bimap will be serializable if the specified bimap is serializable. * * @param bimap the bimap for which an unmodifiable view is to be returned * @return an unmodifiable view of the specified bimap */ public static BiMap unmodifiableBiMap(BiMap bimap) { return new UnmodifiableBiMap<>(bimap, null); } /** @see Maps#unmodifiableBiMap(BiMap) */ private static class UnmodifiableBiMap extends ForwardingMap implements BiMap, Serializable { final Map unmodifiableMap; final BiMap delegate; @RetainedWith @NullableDecl BiMap inverse; @NullableDecl transient Set values; UnmodifiableBiMap(BiMap delegate, @NullableDecl BiMap inverse) { unmodifiableMap = Collections.unmodifiableMap(delegate); this.delegate = delegate; this.inverse = inverse; } @Override protected Map delegate() { return unmodifiableMap; } @Override public V forcePut(K key, V value) { throw new UnsupportedOperationException(); } @Override public BiMap inverse() { BiMap result = inverse; return (result == null) ? inverse = new UnmodifiableBiMap<>(delegate.inverse(), this) : result; } @Override public Set values() { Set result = values; return (result == null) ? values = Collections.unmodifiableSet(delegate.values()) : result; } private static final long serialVersionUID = 0; } /** * Returns a view of a map where each value is transformed by a function. All other properties of * the map, such as iteration order, are left intact. For example, the code: * *

{@code
   * Map map = ImmutableMap.of("a", 4, "b", 9);
   * Function sqrt =
   *     new Function() {
   *       public Double apply(Integer in) {
   *         return Math.sqrt((int) in);
   *       }
   *     };
   * Map transformed = Maps.transformValues(map, sqrt);
   * System.out.println(transformed);
   * }
* * ... prints {@code {a=2.0, b=3.0}}. * *

Changes in the underlying map are reflected in this view. Conversely, this view supports * removal operations, and these are reflected in the underlying map. * *

It's acceptable for the underlying map to contain null keys, and even null values provided * that the function is capable of accepting null input. The transformed map might contain null * values, if the function sometimes gives a null result. * *

The returned map is not thread-safe or serializable, even if the underlying map is. * *

The function is applied lazily, invoked when needed. This is necessary for the returned map * to be a view, but it means that the function will be applied many times for bulk operations * like {@link Map#containsValue} and {@code Map.toString()}. For this to perform well, {@code * function} should be fast. To avoid lazy evaluation when the returned map doesn't need to be a * view, copy the returned map into a new map of your choosing. */ public static Map transformValues( Map fromMap, Function function) { return transformEntries(fromMap, asEntryTransformer(function)); } /** * Returns a view of a sorted map where each value is transformed by a function. All other * properties of the map, such as iteration order, are left intact. For example, the code: * *

{@code
   * SortedMap map = ImmutableSortedMap.of("a", 4, "b", 9);
   * Function sqrt =
   *     new Function() {
   *       public Double apply(Integer in) {
   *         return Math.sqrt((int) in);
   *       }
   *     };
   * SortedMap transformed =
   *      Maps.transformValues(map, sqrt);
   * System.out.println(transformed);
   * }
* * ... prints {@code {a=2.0, b=3.0}}. * *

Changes in the underlying map are reflected in this view. Conversely, this view supports * removal operations, and these are reflected in the underlying map. * *

It's acceptable for the underlying map to contain null keys, and even null values provided * that the function is capable of accepting null input. The transformed map might contain null * values, if the function sometimes gives a null result. * *

The returned map is not thread-safe or serializable, even if the underlying map is. * *

The function is applied lazily, invoked when needed. This is necessary for the returned map * to be a view, but it means that the function will be applied many times for bulk operations * like {@link Map#containsValue} and {@code Map.toString()}. For this to perform well, {@code * function} should be fast. To avoid lazy evaluation when the returned map doesn't need to be a * view, copy the returned map into a new map of your choosing. * * @since 11.0 */ public static SortedMap transformValues( SortedMap fromMap, Function function) { return transformEntries(fromMap, asEntryTransformer(function)); } /** * Returns a view of a navigable map where each value is transformed by a function. All other * properties of the map, such as iteration order, are left intact. For example, the code: * *

{@code
   * NavigableMap map = Maps.newTreeMap();
   * map.put("a", 4);
   * map.put("b", 9);
   * Function sqrt =
   *     new Function() {
   *       public Double apply(Integer in) {
   *         return Math.sqrt((int) in);
   *       }
   *     };
   * NavigableMap transformed =
   *      Maps.transformNavigableValues(map, sqrt);
   * System.out.println(transformed);
   * }
* * ... prints {@code {a=2.0, b=3.0}}. * *

Changes in the underlying map are reflected in this view. Conversely, this view supports * removal operations, and these are reflected in the underlying map. * *

It's acceptable for the underlying map to contain null keys, and even null values provided * that the function is capable of accepting null input. The transformed map might contain null * values, if the function sometimes gives a null result. * *

The returned map is not thread-safe or serializable, even if the underlying map is. * *

The function is applied lazily, invoked when needed. This is necessary for the returned map * to be a view, but it means that the function will be applied many times for bulk operations * like {@link Map#containsValue} and {@code Map.toString()}. For this to perform well, {@code * function} should be fast. To avoid lazy evaluation when the returned map doesn't need to be a * view, copy the returned map into a new map of your choosing. * * @since 13.0 */ @GwtIncompatible // NavigableMap public static NavigableMap transformValues( NavigableMap fromMap, Function function) { return transformEntries(fromMap, asEntryTransformer(function)); } /** * Returns a view of a map whose values are derived from the original map's entries. In contrast * to {@link #transformValues}, this method's entry-transformation logic may depend on the key as * well as the value. * *

All other properties of the transformed map, such as iteration order, are left intact. For * example, the code: * *

{@code
   * Map options =
   *     ImmutableMap.of("verbose", true, "sort", false);
   * EntryTransformer flagPrefixer =
   *     new EntryTransformer() {
   *       public String transformEntry(String key, Boolean value) {
   *         return value ? key : "no" + key;
   *       }
   *     };
   * Map transformed =
   *     Maps.transformEntries(options, flagPrefixer);
   * System.out.println(transformed);
   * }
* * ... prints {@code {verbose=verbose, sort=nosort}}. * *

Changes in the underlying map are reflected in this view. Conversely, this view supports * removal operations, and these are reflected in the underlying map. * *

It's acceptable for the underlying map to contain null keys and null values provided that * the transformer is capable of accepting null inputs. The transformed map might contain null * values if the transformer sometimes gives a null result. * *

The returned map is not thread-safe or serializable, even if the underlying map is. * *

The transformer is applied lazily, invoked when needed. This is necessary for the returned * map to be a view, but it means that the transformer will be applied many times for bulk * operations like {@link Map#containsValue} and {@link Object#toString}. For this to perform * well, {@code transformer} should be fast. To avoid lazy evaluation when the returned map * doesn't need to be a view, copy the returned map into a new map of your choosing. * *

Warning: This method assumes that for any instance {@code k} of {@code * EntryTransformer} key type {@code K}, {@code k.equals(k2)} implies that {@code k2} is also of * type {@code K}. Using an {@code EntryTransformer} key type for which this may not hold, such as * {@code ArrayList}, may risk a {@code ClassCastException} when calling methods on the * transformed map. * * @since 7.0 */ public static Map transformEntries( Map fromMap, EntryTransformer transformer) { return new TransformedEntriesMap<>(fromMap, transformer); } /** * Returns a view of a sorted map whose values are derived from the original sorted map's entries. * In contrast to {@link #transformValues}, this method's entry-transformation logic may depend on * the key as well as the value. * *

All other properties of the transformed map, such as iteration order, are left intact. For * example, the code: * *

{@code
   * Map options =
   *     ImmutableSortedMap.of("verbose", true, "sort", false);
   * EntryTransformer flagPrefixer =
   *     new EntryTransformer() {
   *       public String transformEntry(String key, Boolean value) {
   *         return value ? key : "yes" + key;
   *       }
   *     };
   * SortedMap transformed =
   *     Maps.transformEntries(options, flagPrefixer);
   * System.out.println(transformed);
   * }
* * ... prints {@code {sort=yessort, verbose=verbose}}. * *

Changes in the underlying map are reflected in this view. Conversely, this view supports * removal operations, and these are reflected in the underlying map. * *

It's acceptable for the underlying map to contain null keys and null values provided that * the transformer is capable of accepting null inputs. The transformed map might contain null * values if the transformer sometimes gives a null result. * *

The returned map is not thread-safe or serializable, even if the underlying map is. * *

The transformer is applied lazily, invoked when needed. This is necessary for the returned * map to be a view, but it means that the transformer will be applied many times for bulk * operations like {@link Map#containsValue} and {@link Object#toString}. For this to perform * well, {@code transformer} should be fast. To avoid lazy evaluation when the returned map * doesn't need to be a view, copy the returned map into a new map of your choosing. * *

Warning: This method assumes that for any instance {@code k} of {@code * EntryTransformer} key type {@code K}, {@code k.equals(k2)} implies that {@code k2} is also of * type {@code K}. Using an {@code EntryTransformer} key type for which this may not hold, such as * {@code ArrayList}, may risk a {@code ClassCastException} when calling methods on the * transformed map. * * @since 11.0 */ public static SortedMap transformEntries( SortedMap fromMap, EntryTransformer transformer) { return new TransformedEntriesSortedMap<>(fromMap, transformer); } /** * Returns a view of a navigable map whose values are derived from the original navigable map's * entries. In contrast to {@link #transformValues}, this method's entry-transformation logic may * depend on the key as well as the value. * *

All other properties of the transformed map, such as iteration order, are left intact. For * example, the code: * *

{@code
   * NavigableMap options = Maps.newTreeMap();
   * options.put("verbose", false);
   * options.put("sort", true);
   * EntryTransformer flagPrefixer =
   *     new EntryTransformer() {
   *       public String transformEntry(String key, Boolean value) {
   *         return value ? key : ("yes" + key);
   *       }
   *     };
   * NavigableMap transformed =
   *     LabsMaps.transformNavigableEntries(options, flagPrefixer);
   * System.out.println(transformed);
   * }
* * ... prints {@code {sort=yessort, verbose=verbose}}. * *

Changes in the underlying map are reflected in this view. Conversely, this view supports * removal operations, and these are reflected in the underlying map. * *

It's acceptable for the underlying map to contain null keys and null values provided that * the transformer is capable of accepting null inputs. The transformed map might contain null * values if the transformer sometimes gives a null result. * *

The returned map is not thread-safe or serializable, even if the underlying map is. * *

The transformer is applied lazily, invoked when needed. This is necessary for the returned * map to be a view, but it means that the transformer will be applied many times for bulk * operations like {@link Map#containsValue} and {@link Object#toString}. For this to perform * well, {@code transformer} should be fast. To avoid lazy evaluation when the returned map * doesn't need to be a view, copy the returned map into a new map of your choosing. * *

Warning: This method assumes that for any instance {@code k} of {@code * EntryTransformer} key type {@code K}, {@code k.equals(k2)} implies that {@code k2} is also of * type {@code K}. Using an {@code EntryTransformer} key type for which this may not hold, such as * {@code ArrayList}, may risk a {@code ClassCastException} when calling methods on the * transformed map. * * @since 13.0 */ @GwtIncompatible // NavigableMap public static NavigableMap transformEntries( NavigableMap fromMap, EntryTransformer transformer) { return new TransformedEntriesNavigableMap<>(fromMap, transformer); } /** * A transformation of the value of a key-value pair, using both key and value as inputs. To apply * the transformation to a map, use {@link Maps#transformEntries(Map, EntryTransformer)}. * * @param the key type of the input and output entries * @param the value type of the input entry * @param the value type of the output entry * @since 7.0 */ public interface EntryTransformer { /** * Determines an output value based on a key-value pair. This method is generally * expected, but not absolutely required, to have the following properties: * *

    *
  • Its execution does not cause any observable side effects. *
  • The computation is consistent with equals; that is, {@link Objects#equal * Objects.equal}{@code (k1, k2) &&} {@link Objects#equal}{@code (v1, v2)} implies that * {@code Objects.equal(transformer.transform(k1, v1), transformer.transform(k2, v2))}. *
* * @throws NullPointerException if the key or value is null and this transformer does not accept * null arguments */ V2 transformEntry(@NullableDecl K key, @NullableDecl V1 value); } /** Views a function as an entry transformer that ignores the entry key. */ static EntryTransformer asEntryTransformer( final Function function) { checkNotNull(function); return new EntryTransformer() { @Override public V2 transformEntry(K key, V1 value) { return function.apply(value); } }; } static Function asValueToValueFunction( final EntryTransformer transformer, final K key) { checkNotNull(transformer); return new Function() { @Override public V2 apply(@NullableDecl V1 v1) { return transformer.transformEntry(key, v1); } }; } /** Views an entry transformer as a function from {@code Entry} to values. */ static Function, V2> asEntryToValueFunction( final EntryTransformer transformer) { checkNotNull(transformer); return new Function, V2>() { @Override public V2 apply(Entry entry) { return transformer.transformEntry(entry.getKey(), entry.getValue()); } }; } /** Returns a view of an entry transformed by the specified transformer. */ static Entry transformEntry( final EntryTransformer transformer, final Entry entry) { checkNotNull(transformer); checkNotNull(entry); return new AbstractMapEntry() { @Override public K getKey() { return entry.getKey(); } @Override public V2 getValue() { return transformer.transformEntry(entry.getKey(), entry.getValue()); } }; } /** Views an entry transformer as a function from entries to entries. */ static Function, Entry> asEntryToEntryFunction( final EntryTransformer transformer) { checkNotNull(transformer); return new Function, Entry>() { @Override public Entry apply(final Entry entry) { return transformEntry(transformer, entry); } }; } static class TransformedEntriesMap extends IteratorBasedAbstractMap { final Map fromMap; final EntryTransformer transformer; TransformedEntriesMap( Map fromMap, EntryTransformer transformer) { this.fromMap = checkNotNull(fromMap); this.transformer = checkNotNull(transformer); } @Override public int size() { return fromMap.size(); } @Override public boolean containsKey(Object key) { return fromMap.containsKey(key); } // safe as long as the user followed the Warning in the javadoc @SuppressWarnings("unchecked") @Override public V2 get(Object key) { V1 value = fromMap.get(key); return (value != null || fromMap.containsKey(key)) ? transformer.transformEntry((K) key, value) : null; } // safe as long as the user followed the Warning in the javadoc @SuppressWarnings("unchecked") @Override public V2 remove(Object key) { return fromMap.containsKey(key) ? transformer.transformEntry((K) key, fromMap.remove(key)) : null; } @Override public void clear() { fromMap.clear(); } @Override public Set keySet() { return fromMap.keySet(); } @Override Iterator> entryIterator() { return Iterators.transform( fromMap.entrySet().iterator(), Maps.asEntryToEntryFunction(transformer)); } @Override public Collection values() { return new Values<>(this); } } static class TransformedEntriesSortedMap extends TransformedEntriesMap implements SortedMap { protected SortedMap fromMap() { return (SortedMap) fromMap; } TransformedEntriesSortedMap( SortedMap fromMap, EntryTransformer transformer) { super(fromMap, transformer); } @Override public Comparator comparator() { return fromMap().comparator(); } @Override public K firstKey() { return fromMap().firstKey(); } @Override public SortedMap headMap(K toKey) { return transformEntries(fromMap().headMap(toKey), transformer); } @Override public K lastKey() { return fromMap().lastKey(); } @Override public SortedMap subMap(K fromKey, K toKey) { return transformEntries(fromMap().subMap(fromKey, toKey), transformer); } @Override public SortedMap tailMap(K fromKey) { return transformEntries(fromMap().tailMap(fromKey), transformer); } } @GwtIncompatible // NavigableMap private static class TransformedEntriesNavigableMap extends TransformedEntriesSortedMap implements NavigableMap { TransformedEntriesNavigableMap( NavigableMap fromMap, EntryTransformer transformer) { super(fromMap, transformer); } @Override public Entry ceilingEntry(K key) { return transformEntry(fromMap().ceilingEntry(key)); } @Override public K ceilingKey(K key) { return fromMap().ceilingKey(key); } @Override public NavigableSet descendingKeySet() { return fromMap().descendingKeySet(); } @Override public NavigableMap descendingMap() { return transformEntries(fromMap().descendingMap(), transformer); } @Override public Entry firstEntry() { return transformEntry(fromMap().firstEntry()); } @Override public Entry floorEntry(K key) { return transformEntry(fromMap().floorEntry(key)); } @Override public K floorKey(K key) { return fromMap().floorKey(key); } @Override public NavigableMap headMap(K toKey) { return headMap(toKey, false); } @Override public NavigableMap headMap(K toKey, boolean inclusive) { return transformEntries(fromMap().headMap(toKey, inclusive), transformer); } @Override public Entry higherEntry(K key) { return transformEntry(fromMap().higherEntry(key)); } @Override public K higherKey(K key) { return fromMap().higherKey(key); } @Override public Entry lastEntry() { return transformEntry(fromMap().lastEntry()); } @Override public Entry lowerEntry(K key) { return transformEntry(fromMap().lowerEntry(key)); } @Override public K lowerKey(K key) { return fromMap().lowerKey(key); } @Override public NavigableSet navigableKeySet() { return fromMap().navigableKeySet(); } @Override public Entry pollFirstEntry() { return transformEntry(fromMap().pollFirstEntry()); } @Override public Entry pollLastEntry() { return transformEntry(fromMap().pollLastEntry()); } @Override public NavigableMap subMap( K fromKey, boolean fromInclusive, K toKey, boolean toInclusive) { return transformEntries( fromMap().subMap(fromKey, fromInclusive, toKey, toInclusive), transformer); } @Override public NavigableMap subMap(K fromKey, K toKey) { return subMap(fromKey, true, toKey, false); } @Override public NavigableMap tailMap(K fromKey) { return tailMap(fromKey, true); } @Override public NavigableMap tailMap(K fromKey, boolean inclusive) { return transformEntries(fromMap().tailMap(fromKey, inclusive), transformer); } @NullableDecl private Entry transformEntry(@NullableDecl Entry entry) { return (entry == null) ? null : Maps.transformEntry(transformer, entry); } @Override protected NavigableMap fromMap() { return (NavigableMap) super.fromMap(); } } static Predicate> keyPredicateOnEntries(Predicate keyPredicate) { return compose(keyPredicate, Maps.keyFunction()); } static Predicate> valuePredicateOnEntries(Predicate valuePredicate) { return compose(valuePredicate, Maps.valueFunction()); } /** * Returns a map containing the mappings in {@code unfiltered} whose keys satisfy a predicate. The * returned map is a live view of {@code unfiltered}; changes to one affect the other. * *

The resulting map's {@code keySet()}, {@code entrySet()}, and {@code values()} views have * iterators that don't support {@code remove()}, but all other methods are supported by the map * and its views. When given a key that doesn't satisfy the predicate, the map's {@code put()} and * {@code putAll()} methods throw an {@link IllegalArgumentException}. * *

When methods such as {@code removeAll()} and {@code clear()} are called on the filtered map * or its views, only mappings whose keys satisfy the filter will be removed from the underlying * map. * *

The returned map isn't threadsafe or serializable, even if {@code unfiltered} is. * *

Many of the filtered map's methods, such as {@code size()}, iterate across every key/value * mapping in the underlying map and determine which satisfy the filter. When a live view is * not needed, it may be faster to copy the filtered map and use the copy. * *

Warning: {@code keyPredicate} must be consistent with equals, as documented at * {@link Predicate#apply}. Do not provide a predicate such as {@code * Predicates.instanceOf(ArrayList.class)}, which is inconsistent with equals. */ public static Map filterKeys( Map unfiltered, final Predicate keyPredicate) { checkNotNull(keyPredicate); Predicate> entryPredicate = keyPredicateOnEntries(keyPredicate); return (unfiltered instanceof AbstractFilteredMap) ? filterFiltered((AbstractFilteredMap) unfiltered, entryPredicate) : new FilteredKeyMap(checkNotNull(unfiltered), keyPredicate, entryPredicate); } /** * Returns a sorted map containing the mappings in {@code unfiltered} whose keys satisfy a * predicate. The returned map is a live view of {@code unfiltered}; changes to one affect the * other. * *

The resulting map's {@code keySet()}, {@code entrySet()}, and {@code values()} views have * iterators that don't support {@code remove()}, but all other methods are supported by the map * and its views. When given a key that doesn't satisfy the predicate, the map's {@code put()} and * {@code putAll()} methods throw an {@link IllegalArgumentException}. * *

When methods such as {@code removeAll()} and {@code clear()} are called on the filtered map * or its views, only mappings whose keys satisfy the filter will be removed from the underlying * map. * *

The returned map isn't threadsafe or serializable, even if {@code unfiltered} is. * *

Many of the filtered map's methods, such as {@code size()}, iterate across every key/value * mapping in the underlying map and determine which satisfy the filter. When a live view is * not needed, it may be faster to copy the filtered map and use the copy. * *

Warning: {@code keyPredicate} must be consistent with equals, as documented at * {@link Predicate#apply}. Do not provide a predicate such as {@code * Predicates.instanceOf(ArrayList.class)}, which is inconsistent with equals. * * @since 11.0 */ public static SortedMap filterKeys( SortedMap unfiltered, final Predicate keyPredicate) { // TODO(lowasser): Return a subclass of Maps.FilteredKeyMap for slightly better // performance. return filterEntries(unfiltered, Maps.keyPredicateOnEntries(keyPredicate)); } /** * Returns a navigable map containing the mappings in {@code unfiltered} whose keys satisfy a * predicate. The returned map is a live view of {@code unfiltered}; changes to one affect the * other. * *

The resulting map's {@code keySet()}, {@code entrySet()}, and {@code values()} views have * iterators that don't support {@code remove()}, but all other methods are supported by the map * and its views. When given a key that doesn't satisfy the predicate, the map's {@code put()} and * {@code putAll()} methods throw an {@link IllegalArgumentException}. * *

When methods such as {@code removeAll()} and {@code clear()} are called on the filtered map * or its views, only mappings whose keys satisfy the filter will be removed from the underlying * map. * *

The returned map isn't threadsafe or serializable, even if {@code unfiltered} is. * *

Many of the filtered map's methods, such as {@code size()}, iterate across every key/value * mapping in the underlying map and determine which satisfy the filter. When a live view is * not needed, it may be faster to copy the filtered map and use the copy. * *

Warning: {@code keyPredicate} must be consistent with equals, as documented at * {@link Predicate#apply}. Do not provide a predicate such as {@code * Predicates.instanceOf(ArrayList.class)}, which is inconsistent with equals. * * @since 14.0 */ @GwtIncompatible // NavigableMap public static NavigableMap filterKeys( NavigableMap unfiltered, final Predicate keyPredicate) { // TODO(lowasser): Return a subclass of Maps.FilteredKeyMap for slightly better // performance. return filterEntries(unfiltered, Maps.keyPredicateOnEntries(keyPredicate)); } /** * Returns a bimap containing the mappings in {@code unfiltered} whose keys satisfy a predicate. * The returned bimap is a live view of {@code unfiltered}; changes to one affect the other. * *

The resulting bimap's {@code keySet()}, {@code entrySet()}, and {@code values()} views have * iterators that don't support {@code remove()}, but all other methods are supported by the bimap * and its views. When given a key that doesn't satisfy the predicate, the bimap's {@code put()}, * {@code forcePut()} and {@code putAll()} methods throw an {@link IllegalArgumentException}. * *

When methods such as {@code removeAll()} and {@code clear()} are called on the filtered * bimap or its views, only mappings that satisfy the filter will be removed from the underlying * bimap. * *

The returned bimap isn't threadsafe or serializable, even if {@code unfiltered} is. * *

Many of the filtered bimap's methods, such as {@code size()}, iterate across every key in * the underlying bimap and determine which satisfy the filter. When a live view is not * needed, it may be faster to copy the filtered bimap and use the copy. * *

Warning: {@code entryPredicate} must be consistent with equals , as documented * at {@link Predicate#apply}. * * @since 14.0 */ public static BiMap filterKeys( BiMap unfiltered, final Predicate keyPredicate) { checkNotNull(keyPredicate); return filterEntries(unfiltered, Maps.keyPredicateOnEntries(keyPredicate)); } /** * Returns a map containing the mappings in {@code unfiltered} whose values satisfy a predicate. * The returned map is a live view of {@code unfiltered}; changes to one affect the other. * *

The resulting map's {@code keySet()}, {@code entrySet()}, and {@code values()} views have * iterators that don't support {@code remove()}, but all other methods are supported by the map * and its views. When given a value that doesn't satisfy the predicate, the map's {@code put()}, * {@code putAll()}, and {@link Entry#setValue} methods throw an {@link IllegalArgumentException}. * *

When methods such as {@code removeAll()} and {@code clear()} are called on the filtered map * or its views, only mappings whose values satisfy the filter will be removed from the underlying * map. * *

The returned map isn't threadsafe or serializable, even if {@code unfiltered} is. * *

Many of the filtered map's methods, such as {@code size()}, iterate across every key/value * mapping in the underlying map and determine which satisfy the filter. When a live view is * not needed, it may be faster to copy the filtered map and use the copy. * *

Warning: {@code valuePredicate} must be consistent with equals, as documented * at {@link Predicate#apply}. Do not provide a predicate such as {@code * Predicates.instanceOf(ArrayList.class)}, which is inconsistent with equals. */ public static Map filterValues( Map unfiltered, final Predicate valuePredicate) { return filterEntries(unfiltered, Maps.valuePredicateOnEntries(valuePredicate)); } /** * Returns a sorted map containing the mappings in {@code unfiltered} whose values satisfy a * predicate. The returned map is a live view of {@code unfiltered}; changes to one affect the * other. * *

The resulting map's {@code keySet()}, {@code entrySet()}, and {@code values()} views have * iterators that don't support {@code remove()}, but all other methods are supported by the map * and its views. When given a value that doesn't satisfy the predicate, the map's {@code put()}, * {@code putAll()}, and {@link Entry#setValue} methods throw an {@link IllegalArgumentException}. * *

When methods such as {@code removeAll()} and {@code clear()} are called on the filtered map * or its views, only mappings whose values satisfy the filter will be removed from the underlying * map. * *

The returned map isn't threadsafe or serializable, even if {@code unfiltered} is. * *

Many of the filtered map's methods, such as {@code size()}, iterate across every key/value * mapping in the underlying map and determine which satisfy the filter. When a live view is * not needed, it may be faster to copy the filtered map and use the copy. * *

Warning: {@code valuePredicate} must be consistent with equals, as documented * at {@link Predicate#apply}. Do not provide a predicate such as {@code * Predicates.instanceOf(ArrayList.class)}, which is inconsistent with equals. * * @since 11.0 */ public static SortedMap filterValues( SortedMap unfiltered, final Predicate valuePredicate) { return filterEntries(unfiltered, Maps.valuePredicateOnEntries(valuePredicate)); } /** * Returns a navigable map containing the mappings in {@code unfiltered} whose values satisfy a * predicate. The returned map is a live view of {@code unfiltered}; changes to one affect the * other. * *

The resulting map's {@code keySet()}, {@code entrySet()}, and {@code values()} views have * iterators that don't support {@code remove()}, but all other methods are supported by the map * and its views. When given a value that doesn't satisfy the predicate, the map's {@code put()}, * {@code putAll()}, and {@link Entry#setValue} methods throw an {@link IllegalArgumentException}. * *

When methods such as {@code removeAll()} and {@code clear()} are called on the filtered map * or its views, only mappings whose values satisfy the filter will be removed from the underlying * map. * *

The returned map isn't threadsafe or serializable, even if {@code unfiltered} is. * *

Many of the filtered map's methods, such as {@code size()}, iterate across every key/value * mapping in the underlying map and determine which satisfy the filter. When a live view is * not needed, it may be faster to copy the filtered map and use the copy. * *

Warning: {@code valuePredicate} must be consistent with equals, as documented * at {@link Predicate#apply}. Do not provide a predicate such as {@code * Predicates.instanceOf(ArrayList.class)}, which is inconsistent with equals. * * @since 14.0 */ @GwtIncompatible // NavigableMap public static NavigableMap filterValues( NavigableMap unfiltered, final Predicate valuePredicate) { return filterEntries(unfiltered, Maps.valuePredicateOnEntries(valuePredicate)); } /** * Returns a bimap containing the mappings in {@code unfiltered} whose values satisfy a predicate. * The returned bimap is a live view of {@code unfiltered}; changes to one affect the other. * *

The resulting bimap's {@code keySet()}, {@code entrySet()}, and {@code values()} views have * iterators that don't support {@code remove()}, but all other methods are supported by the bimap * and its views. When given a value that doesn't satisfy the predicate, the bimap's {@code * put()}, {@code forcePut()} and {@code putAll()} methods throw an {@link * IllegalArgumentException}. Similarly, the map's entries have a {@link Entry#setValue} method * that throws an {@link IllegalArgumentException} when the provided value doesn't satisfy the * predicate. * *

When methods such as {@code removeAll()} and {@code clear()} are called on the filtered * bimap or its views, only mappings that satisfy the filter will be removed from the underlying * bimap. * *

The returned bimap isn't threadsafe or serializable, even if {@code unfiltered} is. * *

Many of the filtered bimap's methods, such as {@code size()}, iterate across every value in * the underlying bimap and determine which satisfy the filter. When a live view is not * needed, it may be faster to copy the filtered bimap and use the copy. * *

Warning: {@code entryPredicate} must be consistent with equals , as documented * at {@link Predicate#apply}. * * @since 14.0 */ public static BiMap filterValues( BiMap unfiltered, final Predicate valuePredicate) { return filterEntries(unfiltered, Maps.valuePredicateOnEntries(valuePredicate)); } /** * Returns a map containing the mappings in {@code unfiltered} that satisfy a predicate. The * returned map is a live view of {@code unfiltered}; changes to one affect the other. * *

The resulting map's {@code keySet()}, {@code entrySet()}, and {@code values()} views have * iterators that don't support {@code remove()}, but all other methods are supported by the map * and its views. When given a key/value pair that doesn't satisfy the predicate, the map's {@code * put()} and {@code putAll()} methods throw an {@link IllegalArgumentException}. Similarly, the * map's entries have a {@link Entry#setValue} method that throws an {@link * IllegalArgumentException} when the existing key and the provided value don't satisfy the * predicate. * *

When methods such as {@code removeAll()} and {@code clear()} are called on the filtered map * or its views, only mappings that satisfy the filter will be removed from the underlying map. * *

The returned map isn't threadsafe or serializable, even if {@code unfiltered} is. * *

Many of the filtered map's methods, such as {@code size()}, iterate across every key/value * mapping in the underlying map and determine which satisfy the filter. When a live view is * not needed, it may be faster to copy the filtered map and use the copy. * *

Warning: {@code entryPredicate} must be consistent with equals, as documented * at {@link Predicate#apply}. */ public static Map filterEntries( Map unfiltered, Predicate> entryPredicate) { checkNotNull(entryPredicate); return (unfiltered instanceof AbstractFilteredMap) ? filterFiltered((AbstractFilteredMap) unfiltered, entryPredicate) : new FilteredEntryMap(checkNotNull(unfiltered), entryPredicate); } /** * Returns a sorted map containing the mappings in {@code unfiltered} that satisfy a predicate. * The returned map is a live view of {@code unfiltered}; changes to one affect the other. * *

The resulting map's {@code keySet()}, {@code entrySet()}, and {@code values()} views have * iterators that don't support {@code remove()}, but all other methods are supported by the map * and its views. When given a key/value pair that doesn't satisfy the predicate, the map's {@code * put()} and {@code putAll()} methods throw an {@link IllegalArgumentException}. Similarly, the * map's entries have a {@link Entry#setValue} method that throws an {@link * IllegalArgumentException} when the existing key and the provided value don't satisfy the * predicate. * *

When methods such as {@code removeAll()} and {@code clear()} are called on the filtered map * or its views, only mappings that satisfy the filter will be removed from the underlying map. * *

The returned map isn't threadsafe or serializable, even if {@code unfiltered} is. * *

Many of the filtered map's methods, such as {@code size()}, iterate across every key/value * mapping in the underlying map and determine which satisfy the filter. When a live view is * not needed, it may be faster to copy the filtered map and use the copy. * *

Warning: {@code entryPredicate} must be consistent with equals, as documented * at {@link Predicate#apply}. * * @since 11.0 */ public static SortedMap filterEntries( SortedMap unfiltered, Predicate> entryPredicate) { checkNotNull(entryPredicate); return (unfiltered instanceof FilteredEntrySortedMap) ? filterFiltered((FilteredEntrySortedMap) unfiltered, entryPredicate) : new FilteredEntrySortedMap(checkNotNull(unfiltered), entryPredicate); } /** * Returns a sorted map containing the mappings in {@code unfiltered} that satisfy a predicate. * The returned map is a live view of {@code unfiltered}; changes to one affect the other. * *

The resulting map's {@code keySet()}, {@code entrySet()}, and {@code values()} views have * iterators that don't support {@code remove()}, but all other methods are supported by the map * and its views. When given a key/value pair that doesn't satisfy the predicate, the map's {@code * put()} and {@code putAll()} methods throw an {@link IllegalArgumentException}. Similarly, the * map's entries have a {@link Entry#setValue} method that throws an {@link * IllegalArgumentException} when the existing key and the provided value don't satisfy the * predicate. * *

When methods such as {@code removeAll()} and {@code clear()} are called on the filtered map * or its views, only mappings that satisfy the filter will be removed from the underlying map. * *

The returned map isn't threadsafe or serializable, even if {@code unfiltered} is. * *

Many of the filtered map's methods, such as {@code size()}, iterate across every key/value * mapping in the underlying map and determine which satisfy the filter. When a live view is * not needed, it may be faster to copy the filtered map and use the copy. * *

Warning: {@code entryPredicate} must be consistent with equals, as documented * at {@link Predicate#apply}. * * @since 14.0 */ @GwtIncompatible // NavigableMap public static NavigableMap filterEntries( NavigableMap unfiltered, Predicate> entryPredicate) { checkNotNull(entryPredicate); return (unfiltered instanceof FilteredEntryNavigableMap) ? filterFiltered((FilteredEntryNavigableMap) unfiltered, entryPredicate) : new FilteredEntryNavigableMap(checkNotNull(unfiltered), entryPredicate); } /** * Returns a bimap containing the mappings in {@code unfiltered} that satisfy a predicate. The * returned bimap is a live view of {@code unfiltered}; changes to one affect the other. * *

The resulting bimap's {@code keySet()}, {@code entrySet()}, and {@code values()} views have * iterators that don't support {@code remove()}, but all other methods are supported by the bimap * and its views. When given a key/value pair that doesn't satisfy the predicate, the bimap's * {@code put()}, {@code forcePut()} and {@code putAll()} methods throw an {@link * IllegalArgumentException}. Similarly, the map's entries have an {@link Entry#setValue} method * that throws an {@link IllegalArgumentException} when the existing key and the provided value * don't satisfy the predicate. * *

When methods such as {@code removeAll()} and {@code clear()} are called on the filtered * bimap or its views, only mappings that satisfy the filter will be removed from the underlying * bimap. * *

The returned bimap isn't threadsafe or serializable, even if {@code unfiltered} is. * *

Many of the filtered bimap's methods, such as {@code size()}, iterate across every key/value * mapping in the underlying bimap and determine which satisfy the filter. When a live view is * not needed, it may be faster to copy the filtered bimap and use the copy. * *

Warning: {@code entryPredicate} must be consistent with equals , as documented * at {@link Predicate#apply}. * * @since 14.0 */ public static BiMap filterEntries( BiMap unfiltered, Predicate> entryPredicate) { checkNotNull(unfiltered); checkNotNull(entryPredicate); return (unfiltered instanceof FilteredEntryBiMap) ? filterFiltered((FilteredEntryBiMap) unfiltered, entryPredicate) : new FilteredEntryBiMap(unfiltered, entryPredicate); } /** * Support {@code clear()}, {@code removeAll()}, and {@code retainAll()} when filtering a filtered * map. */ private static Map filterFiltered( AbstractFilteredMap map, Predicate> entryPredicate) { return new FilteredEntryMap<>( map.unfiltered, Predicates.>and(map.predicate, entryPredicate)); } /** * Support {@code clear()}, {@code removeAll()}, and {@code retainAll()} when filtering a filtered * sorted map. */ private static SortedMap filterFiltered( FilteredEntrySortedMap map, Predicate> entryPredicate) { Predicate> predicate = Predicates.>and(map.predicate, entryPredicate); return new FilteredEntrySortedMap<>(map.sortedMap(), predicate); } /** * Support {@code clear()}, {@code removeAll()}, and {@code retainAll()} when filtering a filtered * navigable map. */ @GwtIncompatible // NavigableMap private static NavigableMap filterFiltered( FilteredEntryNavigableMap map, Predicate> entryPredicate) { Predicate> predicate = Predicates.>and(map.entryPredicate, entryPredicate); return new FilteredEntryNavigableMap<>(map.unfiltered, predicate); } /** * Support {@code clear()}, {@code removeAll()}, and {@code retainAll()} when filtering a filtered * map. */ private static BiMap filterFiltered( FilteredEntryBiMap map, Predicate> entryPredicate) { Predicate> predicate = Predicates.>and(map.predicate, entryPredicate); return new FilteredEntryBiMap<>(map.unfiltered(), predicate); } private abstract static class AbstractFilteredMap extends ViewCachingAbstractMap { final Map unfiltered; final Predicate> predicate; AbstractFilteredMap(Map unfiltered, Predicate> predicate) { this.unfiltered = unfiltered; this.predicate = predicate; } boolean apply(@NullableDecl Object key, @NullableDecl V value) { // This method is called only when the key is in the map, implying that // key is a K. @SuppressWarnings("unchecked") K k = (K) key; return predicate.apply(Maps.immutableEntry(k, value)); } @Override public V put(K key, V value) { checkArgument(apply(key, value)); return unfiltered.put(key, value); } @Override public void putAll(Map map) { for (Entry entry : map.entrySet()) { checkArgument(apply(entry.getKey(), entry.getValue())); } unfiltered.putAll(map); } @Override public boolean containsKey(Object key) { return unfiltered.containsKey(key) && apply(key, unfiltered.get(key)); } @Override public V get(Object key) { V value = unfiltered.get(key); return ((value != null) && apply(key, value)) ? value : null; } @Override public boolean isEmpty() { return entrySet().isEmpty(); } @Override public V remove(Object key) { return containsKey(key) ? unfiltered.remove(key) : null; } @Override Collection createValues() { return new FilteredMapValues<>(this, unfiltered, predicate); } } private static final class FilteredMapValues extends Maps.Values { final Map unfiltered; final Predicate> predicate; FilteredMapValues( Map filteredMap, Map unfiltered, Predicate> predicate) { super(filteredMap); this.unfiltered = unfiltered; this.predicate = predicate; } @Override public boolean remove(Object o) { Iterator> entryItr = unfiltered.entrySet().iterator(); while (entryItr.hasNext()) { Entry entry = entryItr.next(); if (predicate.apply(entry) && Objects.equal(entry.getValue(), o)) { entryItr.remove(); return true; } } return false; } @Override public boolean removeAll(Collection collection) { Iterator> entryItr = unfiltered.entrySet().iterator(); boolean result = false; while (entryItr.hasNext()) { Entry entry = entryItr.next(); if (predicate.apply(entry) && collection.contains(entry.getValue())) { entryItr.remove(); result = true; } } return result; } @Override public boolean retainAll(Collection collection) { Iterator> entryItr = unfiltered.entrySet().iterator(); boolean result = false; while (entryItr.hasNext()) { Entry entry = entryItr.next(); if (predicate.apply(entry) && !collection.contains(entry.getValue())) { entryItr.remove(); result = true; } } return result; } @Override public Object[] toArray() { // creating an ArrayList so filtering happens once return Lists.newArrayList(iterator()).toArray(); } @Override public T[] toArray(T[] array) { return Lists.newArrayList(iterator()).toArray(array); } } private static class FilteredKeyMap extends AbstractFilteredMap { final Predicate keyPredicate; FilteredKeyMap( Map unfiltered, Predicate keyPredicate, Predicate> entryPredicate) { super(unfiltered, entryPredicate); this.keyPredicate = keyPredicate; } @Override protected Set> createEntrySet() { return Sets.filter(unfiltered.entrySet(), predicate); } @Override Set createKeySet() { return Sets.filter(unfiltered.keySet(), keyPredicate); } // The cast is called only when the key is in the unfiltered map, implying // that key is a K. @Override @SuppressWarnings("unchecked") public boolean containsKey(Object key) { return unfiltered.containsKey(key) && keyPredicate.apply((K) key); } } static class FilteredEntryMap extends AbstractFilteredMap { /** * Entries in this set satisfy the predicate, but they don't validate the input to {@code * Entry.setValue()}. */ final Set> filteredEntrySet; FilteredEntryMap(Map unfiltered, Predicate> entryPredicate) { super(unfiltered, entryPredicate); filteredEntrySet = Sets.filter(unfiltered.entrySet(), predicate); } @Override protected Set> createEntrySet() { return new EntrySet(); } @WeakOuter private class EntrySet extends ForwardingSet> { @Override protected Set> delegate() { return filteredEntrySet; } @Override public Iterator> iterator() { return new TransformedIterator, Entry>(filteredEntrySet.iterator()) { @Override Entry transform(final Entry entry) { return new ForwardingMapEntry() { @Override protected Entry delegate() { return entry; } @Override public V setValue(V newValue) { checkArgument(apply(getKey(), newValue)); return super.setValue(newValue); } }; } }; } } @Override Set createKeySet() { return new KeySet(); } static boolean removeAllKeys( Map map, Predicate> entryPredicate, Collection keyCollection) { Iterator> entryItr = map.entrySet().iterator(); boolean result = false; while (entryItr.hasNext()) { Entry entry = entryItr.next(); if (entryPredicate.apply(entry) && keyCollection.contains(entry.getKey())) { entryItr.remove(); result = true; } } return result; } static boolean retainAllKeys( Map map, Predicate> entryPredicate, Collection keyCollection) { Iterator> entryItr = map.entrySet().iterator(); boolean result = false; while (entryItr.hasNext()) { Entry entry = entryItr.next(); if (entryPredicate.apply(entry) && !keyCollection.contains(entry.getKey())) { entryItr.remove(); result = true; } } return result; } @WeakOuter class KeySet extends Maps.KeySet { KeySet() { super(FilteredEntryMap.this); } @Override public boolean remove(Object o) { if (containsKey(o)) { unfiltered.remove(o); return true; } return false; } @Override public boolean removeAll(Collection collection) { return removeAllKeys(unfiltered, predicate, collection); } @Override public boolean retainAll(Collection collection) { return retainAllKeys(unfiltered, predicate, collection); } @Override public Object[] toArray() { // creating an ArrayList so filtering happens once return Lists.newArrayList(iterator()).toArray(); } @Override public T[] toArray(T[] array) { return Lists.newArrayList(iterator()).toArray(array); } } } private static class FilteredEntrySortedMap extends FilteredEntryMap implements SortedMap { FilteredEntrySortedMap( SortedMap unfiltered, Predicate> entryPredicate) { super(unfiltered, entryPredicate); } SortedMap sortedMap() { return (SortedMap) unfiltered; } @Override public SortedSet keySet() { return (SortedSet) super.keySet(); } @Override SortedSet createKeySet() { return new SortedKeySet(); } @WeakOuter class SortedKeySet extends KeySet implements SortedSet { @Override public Comparator comparator() { return sortedMap().comparator(); } @Override public SortedSet subSet(K fromElement, K toElement) { return (SortedSet) subMap(fromElement, toElement).keySet(); } @Override public SortedSet headSet(K toElement) { return (SortedSet) headMap(toElement).keySet(); } @Override public SortedSet tailSet(K fromElement) { return (SortedSet) tailMap(fromElement).keySet(); } @Override public K first() { return firstKey(); } @Override public K last() { return lastKey(); } } @Override public Comparator comparator() { return sortedMap().comparator(); } @Override public K firstKey() { // correctly throws NoSuchElementException when filtered map is empty. return keySet().iterator().next(); } @Override public K lastKey() { SortedMap headMap = sortedMap(); while (true) { // correctly throws NoSuchElementException when filtered map is empty. K key = headMap.lastKey(); if (apply(key, unfiltered.get(key))) { return key; } headMap = sortedMap().headMap(key); } } @Override public SortedMap headMap(K toKey) { return new FilteredEntrySortedMap<>(sortedMap().headMap(toKey), predicate); } @Override public SortedMap subMap(K fromKey, K toKey) { return new FilteredEntrySortedMap<>(sortedMap().subMap(fromKey, toKey), predicate); } @Override public SortedMap tailMap(K fromKey) { return new FilteredEntrySortedMap<>(sortedMap().tailMap(fromKey), predicate); } } @GwtIncompatible // NavigableMap private static class FilteredEntryNavigableMap extends AbstractNavigableMap { /* * It's less code to extend AbstractNavigableMap and forward the filtering logic to * FilteredEntryMap than to extend FilteredEntrySortedMap and reimplement all the NavigableMap * methods. */ private final NavigableMap unfiltered; private final Predicate> entryPredicate; private final Map filteredDelegate; FilteredEntryNavigableMap( NavigableMap unfiltered, Predicate> entryPredicate) { this.unfiltered = checkNotNull(unfiltered); this.entryPredicate = entryPredicate; this.filteredDelegate = new FilteredEntryMap<>(unfiltered, entryPredicate); } @Override public Comparator comparator() { return unfiltered.comparator(); } @Override public NavigableSet navigableKeySet() { return new Maps.NavigableKeySet(this) { @Override public boolean removeAll(Collection collection) { return FilteredEntryMap.removeAllKeys(unfiltered, entryPredicate, collection); } @Override public boolean retainAll(Collection collection) { return FilteredEntryMap.retainAllKeys(unfiltered, entryPredicate, collection); } }; } @Override public Collection values() { return new FilteredMapValues<>(this, unfiltered, entryPredicate); } @Override Iterator> entryIterator() { return Iterators.filter(unfiltered.entrySet().iterator(), entryPredicate); } @Override Iterator> descendingEntryIterator() { return Iterators.filter(unfiltered.descendingMap().entrySet().iterator(), entryPredicate); } @Override public int size() { return filteredDelegate.size(); } @Override public boolean isEmpty() { return !Iterables.any(unfiltered.entrySet(), entryPredicate); } @Override @NullableDecl public V get(@NullableDecl Object key) { return filteredDelegate.get(key); } @Override public boolean containsKey(@NullableDecl Object key) { return filteredDelegate.containsKey(key); } @Override public V put(K key, V value) { return filteredDelegate.put(key, value); } @Override public V remove(@NullableDecl Object key) { return filteredDelegate.remove(key); } @Override public void putAll(Map m) { filteredDelegate.putAll(m); } @Override public void clear() { filteredDelegate.clear(); } @Override public Set> entrySet() { return filteredDelegate.entrySet(); } @Override public Entry pollFirstEntry() { return Iterables.removeFirstMatching(unfiltered.entrySet(), entryPredicate); } @Override public Entry pollLastEntry() { return Iterables.removeFirstMatching(unfiltered.descendingMap().entrySet(), entryPredicate); } @Override public NavigableMap descendingMap() { return filterEntries(unfiltered.descendingMap(), entryPredicate); } @Override public NavigableMap subMap( K fromKey, boolean fromInclusive, K toKey, boolean toInclusive) { return filterEntries( unfiltered.subMap(fromKey, fromInclusive, toKey, toInclusive), entryPredicate); } @Override public NavigableMap headMap(K toKey, boolean inclusive) { return filterEntries(unfiltered.headMap(toKey, inclusive), entryPredicate); } @Override public NavigableMap tailMap(K fromKey, boolean inclusive) { return filterEntries(unfiltered.tailMap(fromKey, inclusive), entryPredicate); } } static final class FilteredEntryBiMap extends FilteredEntryMap implements BiMap { @RetainedWith private final BiMap inverse; private static Predicate> inversePredicate( final Predicate> forwardPredicate) { return new Predicate>() { @Override public boolean apply(Entry input) { return forwardPredicate.apply(Maps.immutableEntry(input.getValue(), input.getKey())); } }; } FilteredEntryBiMap(BiMap delegate, Predicate> predicate) { super(delegate, predicate); this.inverse = new FilteredEntryBiMap<>(delegate.inverse(), inversePredicate(predicate), this); } private FilteredEntryBiMap( BiMap delegate, Predicate> predicate, BiMap inverse) { super(delegate, predicate); this.inverse = inverse; } BiMap unfiltered() { return (BiMap) unfiltered; } @Override public V forcePut(@NullableDecl K key, @NullableDecl V value) { checkArgument(apply(key, value)); return unfiltered().forcePut(key, value); } @Override public BiMap inverse() { return inverse; } @Override public Set values() { return inverse.keySet(); } } /** * Returns an unmodifiable view of the specified navigable map. Query operations on the returned * map read through to the specified map, and attempts to modify the returned map, whether direct * or via its views, result in an {@code UnsupportedOperationException}. * *

The returned navigable map will be serializable if the specified navigable map is * serializable. * *

This method's signature will not permit you to convert a {@code NavigableMap} to a {@code NavigableMap}. If it permitted this, the returned map's {@code * comparator()} method might return a {@code Comparator}, which works only on a * particular subtype of {@code K}, but promise that it's a {@code Comparator}, which * must work on any type of {@code K}. * * @param map the navigable map for which an unmodifiable view is to be returned * @return an unmodifiable view of the specified navigable map * @since 12.0 */ @GwtIncompatible // NavigableMap public static NavigableMap unmodifiableNavigableMap( NavigableMap map) { checkNotNull(map); if (map instanceof UnmodifiableNavigableMap) { @SuppressWarnings("unchecked") // covariant NavigableMap result = (NavigableMap) map; return result; } else { return new UnmodifiableNavigableMap<>(map); } } @NullableDecl private static Entry unmodifiableOrNull(@NullableDecl Entry entry) { return (entry == null) ? null : Maps.unmodifiableEntry(entry); } @GwtIncompatible // NavigableMap static class UnmodifiableNavigableMap extends ForwardingSortedMap implements NavigableMap, Serializable { private final NavigableMap delegate; UnmodifiableNavigableMap(NavigableMap delegate) { this.delegate = delegate; } UnmodifiableNavigableMap( NavigableMap delegate, UnmodifiableNavigableMap descendingMap) { this.delegate = delegate; this.descendingMap = descendingMap; } @Override protected SortedMap delegate() { return Collections.unmodifiableSortedMap(delegate); } @Override public Entry lowerEntry(K key) { return unmodifiableOrNull(delegate.lowerEntry(key)); } @Override public K lowerKey(K key) { return delegate.lowerKey(key); } @Override public Entry floorEntry(K key) { return unmodifiableOrNull(delegate.floorEntry(key)); } @Override public K floorKey(K key) { return delegate.floorKey(key); } @Override public Entry ceilingEntry(K key) { return unmodifiableOrNull(delegate.ceilingEntry(key)); } @Override public K ceilingKey(K key) { return delegate.ceilingKey(key); } @Override public Entry higherEntry(K key) { return unmodifiableOrNull(delegate.higherEntry(key)); } @Override public K higherKey(K key) { return delegate.higherKey(key); } @Override public Entry firstEntry() { return unmodifiableOrNull(delegate.firstEntry()); } @Override public Entry lastEntry() { return unmodifiableOrNull(delegate.lastEntry()); } @Override public final Entry pollFirstEntry() { throw new UnsupportedOperationException(); } @Override public final Entry pollLastEntry() { throw new UnsupportedOperationException(); } @NullableDecl private transient UnmodifiableNavigableMap descendingMap; @Override public NavigableMap descendingMap() { UnmodifiableNavigableMap result = descendingMap; return (result == null) ? descendingMap = new UnmodifiableNavigableMap<>(delegate.descendingMap(), this) : result; } @Override public Set keySet() { return navigableKeySet(); } @Override public NavigableSet navigableKeySet() { return Sets.unmodifiableNavigableSet(delegate.navigableKeySet()); } @Override public NavigableSet descendingKeySet() { return Sets.unmodifiableNavigableSet(delegate.descendingKeySet()); } @Override public SortedMap subMap(K fromKey, K toKey) { return subMap(fromKey, true, toKey, false); } @Override public NavigableMap subMap( K fromKey, boolean fromInclusive, K toKey, boolean toInclusive) { return Maps.unmodifiableNavigableMap( delegate.subMap(fromKey, fromInclusive, toKey, toInclusive)); } @Override public SortedMap headMap(K toKey) { return headMap(toKey, false); } @Override public NavigableMap headMap(K toKey, boolean inclusive) { return Maps.unmodifiableNavigableMap(delegate.headMap(toKey, inclusive)); } @Override public SortedMap tailMap(K fromKey) { return tailMap(fromKey, true); } @Override public NavigableMap tailMap(K fromKey, boolean inclusive) { return Maps.unmodifiableNavigableMap(delegate.tailMap(fromKey, inclusive)); } } /** * Returns a synchronized (thread-safe) navigable map backed by the specified navigable map. In * order to guarantee serial access, it is critical that all access to the backing * navigable map is accomplished through the returned navigable map (or its views). * *

It is imperative that the user manually synchronize on the returned navigable map when * iterating over any of its collection views, or the collections views of any of its {@code * descendingMap}, {@code subMap}, {@code headMap} or {@code tailMap} views. * *

{@code
   * NavigableMap map = synchronizedNavigableMap(new TreeMap());
   *
   * // Needn't be in synchronized block
   * NavigableSet set = map.navigableKeySet();
   *
   * synchronized (map) { // Synchronizing on map, not set!
   *   Iterator it = set.iterator(); // Must be in synchronized block
   *   while (it.hasNext()) {
   *     foo(it.next());
   *   }
   * }
   * }
* *

or: * *

{@code
   * NavigableMap map = synchronizedNavigableMap(new TreeMap());
   * NavigableMap map2 = map.subMap(foo, false, bar, true);
   *
   * // Needn't be in synchronized block
   * NavigableSet set2 = map2.descendingKeySet();
   *
   * synchronized (map) { // Synchronizing on map, not map2 or set2!
   *   Iterator it = set2.iterator(); // Must be in synchronized block
   *   while (it.hasNext()) {
   *     foo(it.next());
   *   }
   * }
   * }
* *

Failure to follow this advice may result in non-deterministic behavior. * *

The returned navigable map will be serializable if the specified navigable map is * serializable. * * @param navigableMap the navigable map to be "wrapped" in a synchronized navigable map. * @return a synchronized view of the specified navigable map. * @since 13.0 */ @GwtIncompatible // NavigableMap public static NavigableMap synchronizedNavigableMap( NavigableMap navigableMap) { return Synchronized.navigableMap(navigableMap); } /** * {@code AbstractMap} extension that makes it easy to cache customized keySet, values, and * entrySet views. */ @GwtCompatible abstract static class ViewCachingAbstractMap extends AbstractMap { /** * Creates the entry set to be returned by {@link #entrySet()}. This method is invoked at most * once on a given map, at the time when {@code entrySet} is first called. */ abstract Set> createEntrySet(); @NullableDecl private transient Set> entrySet; @Override public Set> entrySet() { Set> result = entrySet; return (result == null) ? entrySet = createEntrySet() : result; } @NullableDecl private transient Set keySet; @Override public Set keySet() { Set result = keySet; return (result == null) ? keySet = createKeySet() : result; } Set createKeySet() { return new KeySet<>(this); } @NullableDecl private transient Collection values; @Override public Collection values() { Collection result = values; return (result == null) ? values = createValues() : result; } Collection createValues() { return new Values<>(this); } } abstract static class IteratorBasedAbstractMap extends AbstractMap { @Override public abstract int size(); abstract Iterator> entryIterator(); @Override public Set> entrySet() { return new EntrySet() { @Override Map map() { return IteratorBasedAbstractMap.this; } @Override public Iterator> iterator() { return entryIterator(); } }; } @Override public void clear() { Iterators.clear(entryIterator()); } } /** * Delegates to {@link Map#get}. Returns {@code null} on {@code ClassCastException} and {@code * NullPointerException}. */ static V safeGet(Map map, @NullableDecl Object key) { checkNotNull(map); try { return map.get(key); } catch (ClassCastException | NullPointerException e) { return null; } } /** * Delegates to {@link Map#containsKey}. Returns {@code false} on {@code ClassCastException} and * {@code NullPointerException}. */ static boolean safeContainsKey(Map map, Object key) { checkNotNull(map); try { return map.containsKey(key); } catch (ClassCastException | NullPointerException e) { return false; } } /** * Delegates to {@link Map#remove}. Returns {@code null} on {@code ClassCastException} and {@code * NullPointerException}. */ static V safeRemove(Map map, Object key) { checkNotNull(map); try { return map.remove(key); } catch (ClassCastException | NullPointerException e) { return null; } } /** An admittedly inefficient implementation of {@link Map#containsKey}. */ static boolean containsKeyImpl(Map map, @NullableDecl Object key) { return Iterators.contains(keyIterator(map.entrySet().iterator()), key); } /** An implementation of {@link Map#containsValue}. */ static boolean containsValueImpl(Map map, @NullableDecl Object value) { return Iterators.contains(valueIterator(map.entrySet().iterator()), value); } /** * Implements {@code Collection.contains} safely for forwarding collections of map entries. If * {@code o} is an instance of {@code Entry}, it is wrapped using {@link #unmodifiableEntry} to * protect against a possible nefarious equals method. * *

Note that {@code c} is the backing (delegate) collection, rather than the forwarding * collection. * * @param c the delegate (unwrapped) collection of map entries * @param o the object that might be contained in {@code c} * @return {@code true} if {@code c} contains {@code o} */ static boolean containsEntryImpl(Collection> c, Object o) { if (!(o instanceof Entry)) { return false; } return c.contains(unmodifiableEntry((Entry) o)); } /** * Implements {@code Collection.remove} safely for forwarding collections of map entries. If * {@code o} is an instance of {@code Entry}, it is wrapped using {@link #unmodifiableEntry} to * protect against a possible nefarious equals method. * *

Note that {@code c} is backing (delegate) collection, rather than the forwarding collection. * * @param c the delegate (unwrapped) collection of map entries * @param o the object to remove from {@code c} * @return {@code true} if {@code c} was changed */ static boolean removeEntryImpl(Collection> c, Object o) { if (!(o instanceof Entry)) { return false; } return c.remove(unmodifiableEntry((Entry) o)); } /** An implementation of {@link Map#equals}. */ static boolean equalsImpl(Map map, Object object) { if (map == object) { return true; } else if (object instanceof Map) { Map o = (Map) object; return map.entrySet().equals(o.entrySet()); } return false; } /** An implementation of {@link Map#toString}. */ static String toStringImpl(Map map) { StringBuilder sb = Collections2.newStringBuilderForCollection(map.size()).append('{'); boolean first = true; for (Entry entry : map.entrySet()) { if (!first) { sb.append(", "); } first = false; sb.append(entry.getKey()).append('=').append(entry.getValue()); } return sb.append('}').toString(); } /** An implementation of {@link Map#putAll}. */ static void putAllImpl(Map self, Map map) { for (Entry entry : map.entrySet()) { self.put(entry.getKey(), entry.getValue()); } } static class KeySet extends Sets.ImprovedAbstractSet { @Weak final Map map; KeySet(Map map) { this.map = checkNotNull(map); } Map map() { return map; } @Override public Iterator iterator() { return keyIterator(map().entrySet().iterator()); } @Override public int size() { return map().size(); } @Override public boolean isEmpty() { return map().isEmpty(); } @Override public boolean contains(Object o) { return map().containsKey(o); } @Override public boolean remove(Object o) { if (contains(o)) { map().remove(o); return true; } return false; } @Override public void clear() { map().clear(); } } @NullableDecl static K keyOrNull(@NullableDecl Entry entry) { return (entry == null) ? null : entry.getKey(); } @NullableDecl static V valueOrNull(@NullableDecl Entry entry) { return (entry == null) ? null : entry.getValue(); } static class SortedKeySet extends KeySet implements SortedSet { SortedKeySet(SortedMap map) { super(map); } @Override SortedMap map() { return (SortedMap) super.map(); } @Override public Comparator comparator() { return map().comparator(); } @Override public SortedSet subSet(K fromElement, K toElement) { return new SortedKeySet<>(map().subMap(fromElement, toElement)); } @Override public SortedSet headSet(K toElement) { return new SortedKeySet<>(map().headMap(toElement)); } @Override public SortedSet tailSet(K fromElement) { return new SortedKeySet<>(map().tailMap(fromElement)); } @Override public K first() { return map().firstKey(); } @Override public K last() { return map().lastKey(); } } @GwtIncompatible // NavigableMap static class NavigableKeySet extends SortedKeySet implements NavigableSet { NavigableKeySet(NavigableMap map) { super(map); } @Override NavigableMap map() { return (NavigableMap) map; } @Override public K lower(K e) { return map().lowerKey(e); } @Override public K floor(K e) { return map().floorKey(e); } @Override public K ceiling(K e) { return map().ceilingKey(e); } @Override public K higher(K e) { return map().higherKey(e); } @Override public K pollFirst() { return keyOrNull(map().pollFirstEntry()); } @Override public K pollLast() { return keyOrNull(map().pollLastEntry()); } @Override public NavigableSet descendingSet() { return map().descendingKeySet(); } @Override public Iterator descendingIterator() { return descendingSet().iterator(); } @Override public NavigableSet subSet( K fromElement, boolean fromInclusive, K toElement, boolean toInclusive) { return map().subMap(fromElement, fromInclusive, toElement, toInclusive).navigableKeySet(); } @Override public SortedSet subSet(K fromElement, K toElement) { return subSet(fromElement, true, toElement, false); } @Override public NavigableSet headSet(K toElement, boolean inclusive) { return map().headMap(toElement, inclusive).navigableKeySet(); } @Override public SortedSet headSet(K toElement) { return headSet(toElement, false); } @Override public NavigableSet tailSet(K fromElement, boolean inclusive) { return map().tailMap(fromElement, inclusive).navigableKeySet(); } @Override public SortedSet tailSet(K fromElement) { return tailSet(fromElement, true); } } static class Values extends AbstractCollection { @Weak final Map map; Values(Map map) { this.map = checkNotNull(map); } final Map map() { return map; } @Override public Iterator iterator() { return valueIterator(map().entrySet().iterator()); } @Override public boolean remove(Object o) { try { return super.remove(o); } catch (UnsupportedOperationException e) { for (Entry entry : map().entrySet()) { if (Objects.equal(o, entry.getValue())) { map().remove(entry.getKey()); return true; } } return false; } } @Override public boolean removeAll(Collection c) { try { return super.removeAll(checkNotNull(c)); } catch (UnsupportedOperationException e) { Set toRemove = Sets.newHashSet(); for (Entry entry : map().entrySet()) { if (c.contains(entry.getValue())) { toRemove.add(entry.getKey()); } } return map().keySet().removeAll(toRemove); } } @Override public boolean retainAll(Collection c) { try { return super.retainAll(checkNotNull(c)); } catch (UnsupportedOperationException e) { Set toRetain = Sets.newHashSet(); for (Entry entry : map().entrySet()) { if (c.contains(entry.getValue())) { toRetain.add(entry.getKey()); } } return map().keySet().retainAll(toRetain); } } @Override public int size() { return map().size(); } @Override public boolean isEmpty() { return map().isEmpty(); } @Override public boolean contains(@NullableDecl Object o) { return map().containsValue(o); } @Override public void clear() { map().clear(); } } abstract static class EntrySet extends Sets.ImprovedAbstractSet> { abstract Map map(); @Override public int size() { return map().size(); } @Override public void clear() { map().clear(); } @Override public boolean contains(Object o) { if (o instanceof Entry) { Entry entry = (Entry) o; Object key = entry.getKey(); V value = Maps.safeGet(map(), key); return Objects.equal(value, entry.getValue()) && (value != null || map().containsKey(key)); } return false; } @Override public boolean isEmpty() { return map().isEmpty(); } @Override public boolean remove(Object o) { if (contains(o)) { Entry entry = (Entry) o; return map().keySet().remove(entry.getKey()); } return false; } @Override public boolean removeAll(Collection c) { try { return super.removeAll(checkNotNull(c)); } catch (UnsupportedOperationException e) { // if the iterators don't support remove return Sets.removeAllImpl(this, c.iterator()); } } @Override public boolean retainAll(Collection c) { try { return super.retainAll(checkNotNull(c)); } catch (UnsupportedOperationException e) { // if the iterators don't support remove Set keys = Sets.newHashSetWithExpectedSize(c.size()); for (Object o : c) { if (contains(o)) { Entry entry = (Entry) o; keys.add(entry.getKey()); } } return map().keySet().retainAll(keys); } } } @GwtIncompatible // NavigableMap abstract static class DescendingMap extends ForwardingMap implements NavigableMap { abstract NavigableMap forward(); @Override protected final Map delegate() { return forward(); } @NullableDecl private transient Comparator comparator; @SuppressWarnings("unchecked") @Override public Comparator comparator() { Comparator result = comparator; if (result == null) { Comparator forwardCmp = forward().comparator(); if (forwardCmp == null) { forwardCmp = (Comparator) Ordering.natural(); } result = comparator = reverse(forwardCmp); } return result; } // If we inline this, we get a javac error. private static Ordering reverse(Comparator forward) { return Ordering.from(forward).reverse(); } @Override public K firstKey() { return forward().lastKey(); } @Override public K lastKey() { return forward().firstKey(); } @Override public Entry lowerEntry(K key) { return forward().higherEntry(key); } @Override public K lowerKey(K key) { return forward().higherKey(key); } @Override public Entry floorEntry(K key) { return forward().ceilingEntry(key); } @Override public K floorKey(K key) { return forward().ceilingKey(key); } @Override public Entry ceilingEntry(K key) { return forward().floorEntry(key); } @Override public K ceilingKey(K key) { return forward().floorKey(key); } @Override public Entry higherEntry(K key) { return forward().lowerEntry(key); } @Override public K higherKey(K key) { return forward().lowerKey(key); } @Override public Entry firstEntry() { return forward().lastEntry(); } @Override public Entry lastEntry() { return forward().firstEntry(); } @Override public Entry pollFirstEntry() { return forward().pollLastEntry(); } @Override public Entry pollLastEntry() { return forward().pollFirstEntry(); } @Override public NavigableMap descendingMap() { return forward(); } @NullableDecl private transient Set> entrySet; @Override public Set> entrySet() { Set> result = entrySet; return (result == null) ? entrySet = createEntrySet() : result; } abstract Iterator> entryIterator(); Set> createEntrySet() { @WeakOuter class EntrySetImpl extends EntrySet { @Override Map map() { return DescendingMap.this; } @Override public Iterator> iterator() { return entryIterator(); } } return new EntrySetImpl(); } @Override public Set keySet() { return navigableKeySet(); } @NullableDecl private transient NavigableSet navigableKeySet; @Override public NavigableSet navigableKeySet() { NavigableSet result = navigableKeySet; return (result == null) ? navigableKeySet = new NavigableKeySet<>(this) : result; } @Override public NavigableSet descendingKeySet() { return forward().navigableKeySet(); } @Override public NavigableMap subMap( K fromKey, boolean fromInclusive, K toKey, boolean toInclusive) { return forward().subMap(toKey, toInclusive, fromKey, fromInclusive).descendingMap(); } @Override public SortedMap subMap(K fromKey, K toKey) { return subMap(fromKey, true, toKey, false); } @Override public NavigableMap headMap(K toKey, boolean inclusive) { return forward().tailMap(toKey, inclusive).descendingMap(); } @Override public SortedMap headMap(K toKey) { return headMap(toKey, false); } @Override public NavigableMap tailMap(K fromKey, boolean inclusive) { return forward().headMap(fromKey, inclusive).descendingMap(); } @Override public SortedMap tailMap(K fromKey) { return tailMap(fromKey, true); } @Override public Collection values() { return new Values<>(this); } @Override public String toString() { return standardToString(); } } /** Returns a map from the ith element of list to i. */ static ImmutableMap indexMap(Collection list) { ImmutableMap.Builder builder = new ImmutableMap.Builder<>(list.size()); int i = 0; for (E e : list) { builder.put(e, i++); } return builder.build(); } /** * Returns a view of the portion of {@code map} whose keys are contained by {@code range}. * *

This method delegates to the appropriate methods of {@link NavigableMap} (namely {@link * NavigableMap#subMap(Object, boolean, Object, boolean) subMap()}, {@link * NavigableMap#tailMap(Object, boolean) tailMap()}, and {@link NavigableMap#headMap(Object, * boolean) headMap()}) to actually construct the view. Consult these methods for a full * description of the returned view's behavior. * *

Warning: {@code Range}s always represent a range of values using the values' natural * ordering. {@code NavigableMap} on the other hand can specify a custom ordering via a {@link * Comparator}, which can violate the natural ordering. Using this method (or in general using * {@code Range}) with unnaturally-ordered maps can lead to unexpected and undefined behavior. * * @since 20.0 */ @Beta @GwtIncompatible // NavigableMap public static , V> NavigableMap subMap( NavigableMap map, Range range) { if (map.comparator() != null && map.comparator() != Ordering.natural() && range.hasLowerBound() && range.hasUpperBound()) { checkArgument( map.comparator().compare(range.lowerEndpoint(), range.upperEndpoint()) <= 0, "map is using a custom comparator which is inconsistent with the natural ordering."); } if (range.hasLowerBound() && range.hasUpperBound()) { return map.subMap( range.lowerEndpoint(), range.lowerBoundType() == BoundType.CLOSED, range.upperEndpoint(), range.upperBoundType() == BoundType.CLOSED); } else if (range.hasLowerBound()) { return map.tailMap(range.lowerEndpoint(), range.lowerBoundType() == BoundType.CLOSED); } else if (range.hasUpperBound()) { return map.headMap(range.upperEndpoint(), range.upperBoundType() == BoundType.CLOSED); } return checkNotNull(map); } }