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/*
 * Copyright (C) 2009 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.collect.Maps.keyOrNull;

import com.google.common.annotations.GwtCompatible;

import java.util.Arrays;
import java.util.Collections;
import java.util.Comparator;
import java.util.Map;
import java.util.NavigableMap;
import java.util.SortedMap;
import java.util.TreeMap;

import javax.annotation.Nullable;

/**
 * An immutable {@link SortedMap}. Does not permit null keys or values.
 *
 * 

Unlike {@link Collections#unmodifiableSortedMap}, which is a view * of a separate map which can still change, an instance of {@code * ImmutableSortedMap} contains its own data and will never change. * {@code ImmutableSortedMap} is convenient for {@code public static final} maps * ("constant maps") and also lets you easily make a "defensive copy" of a map * provided to your class by a caller. * *

Note: Although this class is not final, it cannot be subclassed as * it has no public or protected constructors. Thus, instances of this class are * guaranteed to be immutable. * *

See the Guava User Guide article on * immutable collections. * * @author Jared Levy * @author Louis Wasserman * @since 2.0 (imported from Google Collections Library; implements {@code * NavigableMap} since 12.0) */ @GwtCompatible(serializable = true, emulated = true) public abstract class ImmutableSortedMap extends ImmutableSortedMapFauxverideShim implements NavigableMap { /* * TODO(kevinb): Confirm that ImmutableSortedMap is faster to construct and * uses less memory than TreeMap; then say so in the class Javadoc. */ private static final Comparator NATURAL_ORDER = Ordering.natural(); private static final ImmutableSortedMap NATURAL_EMPTY_MAP = new EmptyImmutableSortedMap(NATURAL_ORDER); static ImmutableSortedMap emptyMap(Comparator comparator) { if (Ordering.natural().equals(comparator)) { return of(); } else { return new EmptyImmutableSortedMap(comparator); } } static ImmutableSortedMap fromSortedEntries( Comparator comparator, int size, Entry[] entries) { if (size == 0) { return emptyMap(comparator); } ImmutableList.Builder keyBuilder = ImmutableList.builder(); ImmutableList.Builder valueBuilder = ImmutableList.builder(); for (int i = 0; i < size; i++) { Entry entry = entries[i]; keyBuilder.add(entry.getKey()); valueBuilder.add(entry.getValue()); } return new RegularImmutableSortedMap( new RegularImmutableSortedSet(keyBuilder.build(), comparator), valueBuilder.build()); } static ImmutableSortedMap from( ImmutableSortedSet keySet, ImmutableList valueList) { if (keySet.isEmpty()) { return emptyMap(keySet.comparator()); } else { return new RegularImmutableSortedMap( (RegularImmutableSortedSet) keySet, valueList); } } /** * Returns the empty sorted map. */ @SuppressWarnings("unchecked") // unsafe, comparator() returns a comparator on the specified type // TODO(kevinb): evaluate whether or not of().comparator() should return null public static ImmutableSortedMap of() { return (ImmutableSortedMap) NATURAL_EMPTY_MAP; } /** * Returns an immutable map containing a single entry. */ public static , V> ImmutableSortedMap of(K k1, V v1) { return from(ImmutableSortedSet.of(k1), ImmutableList.of(v1)); } /** * Returns an immutable sorted map containing the given entries, sorted by the * natural ordering of their keys. * * @throws IllegalArgumentException if the two keys are equal according to * their natural ordering */ @SuppressWarnings("unchecked") public static , V> ImmutableSortedMap of(K k1, V v1, K k2, V v2) { return fromEntries(Ordering.natural(), false, 2, entryOf(k1, v1), entryOf(k2, v2)); } /** * Returns an immutable sorted map containing the given entries, sorted by the * natural ordering of their keys. * * @throws IllegalArgumentException if any two keys are equal according to * their natural ordering */ @SuppressWarnings("unchecked") public static , V> ImmutableSortedMap of(K k1, V v1, K k2, V v2, K k3, V v3) { return fromEntries(Ordering.natural(), false, 3, entryOf(k1, v1), entryOf(k2, v2), entryOf(k3, v3)); } /** * Returns an immutable sorted map containing the given entries, sorted by the * natural ordering of their keys. * * @throws IllegalArgumentException if any two keys are equal according to * their natural ordering */ @SuppressWarnings("unchecked") public static , V> ImmutableSortedMap of(K k1, V v1, K k2, V v2, K k3, V v3, K k4, V v4) { return fromEntries(Ordering.natural(), false, 4, entryOf(k1, v1), entryOf(k2, v2), entryOf(k3, v3), entryOf(k4, v4)); } /** * Returns an immutable sorted map containing the given entries, sorted by the * natural ordering of their keys. * * @throws IllegalArgumentException if any two keys are equal according to * their natural ordering */ @SuppressWarnings("unchecked") public static , V> ImmutableSortedMap of(K k1, V v1, K k2, V v2, K k3, V v3, K k4, V v4, K k5, V v5) { return fromEntries(Ordering.natural(), false, 5, entryOf(k1, v1), entryOf(k2, v2), entryOf(k3, v3), entryOf(k4, v4), entryOf(k5, v5)); } /** * Returns an immutable map containing the same entries as {@code map}, sorted * by the natural ordering of the keys. * *

Despite the method name, this method attempts to avoid actually copying * the data when it is safe to do so. The exact circumstances under which a * copy will or will not be performed are undocumented and subject to change. * *

This method is not type-safe, as it may be called on a map with keys * that are not mutually comparable. * * @throws ClassCastException if the keys in {@code map} are not mutually * comparable * @throws NullPointerException if any key or value in {@code map} is null * @throws IllegalArgumentException if any two keys are equal according to * their natural ordering */ public static ImmutableSortedMap copyOf( Map map) { // Hack around K not being a subtype of Comparable. // Unsafe, see ImmutableSortedSetFauxverideShim. @SuppressWarnings("unchecked") Ordering naturalOrder = (Ordering) Ordering.natural(); return copyOfInternal(map, naturalOrder); } /** * Returns an immutable map containing the same entries as {@code map}, with * keys sorted by the provided comparator. * *

Despite the method name, this method attempts to avoid actually copying * the data when it is safe to do so. The exact circumstances under which a * copy will or will not be performed are undocumented and subject to change. * * @throws NullPointerException if any key or value in {@code map} is null * @throws IllegalArgumentException if any two keys are equal according to the * comparator */ public static ImmutableSortedMap copyOf( Map map, Comparator comparator) { return copyOfInternal(map, checkNotNull(comparator)); } /** * Returns an immutable map containing the same entries as the provided sorted * map, with the same ordering. * *

Despite the method name, this method attempts to avoid actually copying * the data when it is safe to do so. The exact circumstances under which a * copy will or will not be performed are undocumented and subject to change. * * @throws NullPointerException if any key or value in {@code map} is null */ @SuppressWarnings("unchecked") public static ImmutableSortedMap copyOfSorted( SortedMap map) { Comparator comparator = map.comparator(); if (comparator == null) { // If map has a null comparator, the keys should have a natural ordering, // even though K doesn't explicitly implement Comparable. comparator = (Comparator) NATURAL_ORDER; } return copyOfInternal(map, comparator); } private static ImmutableSortedMap copyOfInternal( Map map, Comparator comparator) { boolean sameComparator = false; if (map instanceof SortedMap) { SortedMap sortedMap = (SortedMap) map; Comparator comparator2 = sortedMap.comparator(); sameComparator = (comparator2 == null) ? comparator == NATURAL_ORDER : comparator.equals(comparator2); } if (sameComparator && (map instanceof ImmutableSortedMap)) { // TODO(kevinb): Prove that this cast is safe, even though // Collections.unmodifiableSortedMap requires the same key type. @SuppressWarnings("unchecked") ImmutableSortedMap kvMap = (ImmutableSortedMap) map; if (!kvMap.isPartialView()) { return kvMap; } } // "adding" type params to an array of a raw type should be safe as // long as no one can ever cast that same array instance back to a // raw type. @SuppressWarnings("unchecked") Entry[] entries = map.entrySet().toArray(new Entry[0]); return fromEntries(comparator, sameComparator, entries.length, entries); } static ImmutableSortedMap fromEntries( Comparator comparator, boolean sameComparator, int size, Entry... entries) { for (int i = 0; i < size; i++) { Entry entry = entries[i]; entries[i] = entryOf(entry.getKey(), entry.getValue()); } if (!sameComparator) { sortEntries(comparator, size, entries); validateEntries(size, entries, comparator); } return fromSortedEntries(comparator, size, entries); } private static void sortEntries( final Comparator comparator, int size, Entry[] entries) { Arrays.sort(entries, 0, size, Ordering.from(comparator).onKeys()); } private static void validateEntries(int size, Entry[] entries, Comparator comparator) { for (int i = 1; i < size; i++) { checkNoConflict(comparator.compare(entries[i - 1].getKey(), entries[i].getKey()) != 0, "key", entries[i - 1], entries[i]); } } /** * Returns a builder that creates immutable sorted maps whose keys are * ordered by their natural ordering. The sorted maps use {@link * Ordering#natural()} as the comparator. */ public static , V> Builder naturalOrder() { return new Builder(Ordering.natural()); } /** * Returns a builder that creates immutable sorted maps with an explicit * comparator. If the comparator has a more general type than the map's keys, * such as creating a {@code SortedMap} with a {@code * Comparator}, use the {@link Builder} constructor instead. * * @throws NullPointerException if {@code comparator} is null */ public static Builder orderedBy(Comparator comparator) { return new Builder(comparator); } /** * Returns a builder that creates immutable sorted maps whose keys are * ordered by the reverse of their natural ordering. */ public static , V> Builder reverseOrder() { return new Builder(Ordering.natural().reverse()); } /** * A builder for creating immutable sorted map instances, especially {@code * public static final} maps ("constant maps"). Example:

   {@code
   *
   *   static final ImmutableSortedMap INT_TO_WORD =
   *       new ImmutableSortedMap.Builder(Ordering.natural())
   *           .put(1, "one")
   *           .put(2, "two")
   *           .put(3, "three")
   *           .build();}
* *

For small immutable sorted maps, the {@code ImmutableSortedMap.of()} * methods are even more convenient. * *

Builder instances can be reused - it is safe to call {@link #build} * multiple times to build multiple maps in series. Each map is a superset of * the maps created before it. * * @since 2.0 (imported from Google Collections Library) */ public static class Builder extends ImmutableMap.Builder { private final Comparator comparator; /** * Creates a new builder. The returned builder is equivalent to the builder * generated by {@link ImmutableSortedMap#orderedBy}. */ @SuppressWarnings("unchecked") public Builder(Comparator comparator) { this.comparator = checkNotNull(comparator); } /** * Associates {@code key} with {@code value} in the built map. Duplicate * keys, according to the comparator (which might be the keys' natural * order), are not allowed, and will cause {@link #build} to fail. */ @Override public Builder put(K key, V value) { super.put(key, value); return this; } /** * Adds the given {@code entry} to the map, making it immutable if * necessary. Duplicate keys, according to the comparator (which might be * the keys' natural order), are not allowed, and will cause {@link #build} * to fail. * * @since 11.0 */ @Override public Builder put(Entry entry) { super.put(entry); return this; } /** * Associates all of the given map's keys and values in the built map. * Duplicate keys, according to the comparator (which might be the keys' * natural order), are not allowed, and will cause {@link #build} to fail. * * @throws NullPointerException if any key or value in {@code map} is null */ @Override public Builder putAll(Map map) { super.putAll(map); return this; } /** * Returns a newly-created immutable sorted map. * * @throws IllegalArgumentException if any two keys are equal according to * the comparator (which might be the keys' natural order) */ @Override public ImmutableSortedMap build() { return fromEntries(comparator, false, size, entries); } } ImmutableSortedMap() { } ImmutableSortedMap(ImmutableSortedMap descendingMap) { this.descendingMap = descendingMap; } @Override public int size() { return values().size(); } @Override public boolean containsValue(@Nullable Object value) { return values().contains(value); } @Override boolean isPartialView() { return keySet().isPartialView() || values().isPartialView(); } /** * Returns an immutable set of the mappings in this map, sorted by the key * ordering. */ @Override public ImmutableSet> entrySet() { return super.entrySet(); } /** * Returns an immutable sorted set of the keys in this map. */ @Override public abstract ImmutableSortedSet keySet(); /** * Returns an immutable collection of the values in this map, sorted by the * ordering of the corresponding keys. */ @Override public abstract ImmutableCollection values(); /** * Returns the comparator that orders the keys, which is * {@link Ordering#natural()} when the natural ordering of the keys is used. * Note that its behavior is not consistent with {@link TreeMap#comparator()}, * which returns {@code null} to indicate natural ordering. */ @Override public Comparator comparator() { return keySet().comparator(); } @Override public K firstKey() { return keySet().first(); } @Override public K lastKey() { return keySet().last(); } /** * This method returns a {@code ImmutableSortedMap}, consisting of the entries * whose keys are less than {@code toKey}. * *

The {@link SortedMap#headMap} documentation states that a submap of a * submap throws an {@link IllegalArgumentException} if passed a {@code toKey} * greater than an earlier {@code toKey}. However, this method doesn't throw * an exception in that situation, but instead keeps the original {@code * toKey}. */ @Override public ImmutableSortedMap headMap(K toKey) { return headMap(toKey, false); } /** * This method returns a {@code ImmutableSortedMap}, consisting of the entries * whose keys are less than (or equal to, if {@code inclusive}) {@code toKey}. * *

The {@link SortedMap#headMap} documentation states that a submap of a * submap throws an {@link IllegalArgumentException} if passed a {@code toKey} * greater than an earlier {@code toKey}. However, this method doesn't throw * an exception in that situation, but instead keeps the original {@code * toKey}. * * @since 12.0 */ @Override public abstract ImmutableSortedMap headMap(K toKey, boolean inclusive); /** * This method returns a {@code ImmutableSortedMap}, consisting of the entries * whose keys ranges from {@code fromKey}, inclusive, to {@code toKey}, * exclusive. * *

The {@link SortedMap#subMap} documentation states that a submap of a * submap throws an {@link IllegalArgumentException} if passed a {@code * fromKey} less than an earlier {@code fromKey}. However, this method doesn't * throw an exception in that situation, but instead keeps the original {@code * fromKey}. Similarly, this method keeps the original {@code toKey}, instead * of throwing an exception, if passed a {@code toKey} greater than an earlier * {@code toKey}. */ @Override public ImmutableSortedMap subMap(K fromKey, K toKey) { return subMap(fromKey, true, toKey, false); } /** * This method returns a {@code ImmutableSortedMap}, consisting of the entries * whose keys ranges from {@code fromKey} to {@code toKey}, inclusive or * exclusive as indicated by the boolean flags. * *

The {@link SortedMap#subMap} documentation states that a submap of a * submap throws an {@link IllegalArgumentException} if passed a {@code * fromKey} less than an earlier {@code fromKey}. However, this method doesn't * throw an exception in that situation, but instead keeps the original {@code * fromKey}. Similarly, this method keeps the original {@code toKey}, instead * of throwing an exception, if passed a {@code toKey} greater than an earlier * {@code toKey}. * * @since 12.0 */ @Override public ImmutableSortedMap subMap(K fromKey, boolean fromInclusive, K toKey, boolean toInclusive) { checkNotNull(fromKey); checkNotNull(toKey); checkArgument(comparator().compare(fromKey, toKey) <= 0, "expected fromKey <= toKey but %s > %s", fromKey, toKey); return headMap(toKey, toInclusive).tailMap(fromKey, fromInclusive); } /** * This method returns a {@code ImmutableSortedMap}, consisting of the entries * whose keys are greater than or equals to {@code fromKey}. * *

The {@link SortedMap#tailMap} documentation states that a submap of a * submap throws an {@link IllegalArgumentException} if passed a {@code * fromKey} less than an earlier {@code fromKey}. However, this method doesn't * throw an exception in that situation, but instead keeps the original {@code * fromKey}. */ @Override public ImmutableSortedMap tailMap(K fromKey) { return tailMap(fromKey, true); } /** * This method returns a {@code ImmutableSortedMap}, consisting of the entries * whose keys are greater than (or equal to, if {@code inclusive}) * {@code fromKey}. * *

The {@link SortedMap#tailMap} documentation states that a submap of a * submap throws an {@link IllegalArgumentException} if passed a {@code * fromKey} less than an earlier {@code fromKey}. However, this method doesn't * throw an exception in that situation, but instead keeps the original {@code * fromKey}. * * @since 12.0 */ @Override public abstract ImmutableSortedMap tailMap(K fromKey, boolean inclusive); @Override public Entry lowerEntry(K key) { return headMap(key, false).lastEntry(); } @Override public K lowerKey(K key) { return keyOrNull(lowerEntry(key)); } @Override public Entry floorEntry(K key) { return headMap(key, true).lastEntry(); } @Override public K floorKey(K key) { return keyOrNull(floorEntry(key)); } @Override public Entry ceilingEntry(K key) { return tailMap(key, true).firstEntry(); } @Override public K ceilingKey(K key) { return keyOrNull(ceilingEntry(key)); } @Override public Entry higherEntry(K key) { return tailMap(key, false).firstEntry(); } @Override public K higherKey(K key) { return keyOrNull(higherEntry(key)); } @Override public Entry firstEntry() { return isEmpty() ? null : entrySet().asList().get(0); } @Override public Entry lastEntry() { return isEmpty() ? null : entrySet().asList().get(size() - 1); } /** * Guaranteed to throw an exception and leave the map unmodified. * * @throws UnsupportedOperationException always * @deprecated Unsupported operation. */ @Deprecated @Override public final Entry pollFirstEntry() { throw new UnsupportedOperationException(); } /** * Guaranteed to throw an exception and leave the map unmodified. * * @throws UnsupportedOperationException always * @deprecated Unsupported operation. */ @Deprecated @Override public final Entry pollLastEntry() { throw new UnsupportedOperationException(); } private transient ImmutableSortedMap descendingMap; @Override public ImmutableSortedMap descendingMap() { ImmutableSortedMap result = descendingMap; if (result == null) { result = descendingMap = createDescendingMap(); } return result; } abstract ImmutableSortedMap createDescendingMap(); @Override public ImmutableSortedSet navigableKeySet() { return keySet(); } @Override public ImmutableSortedSet descendingKeySet() { return keySet().descendingSet(); } /** * Serialized type for all ImmutableSortedMap instances. It captures the * logical contents and they are reconstructed using public factory methods. * This ensures that the implementation types remain as implementation * details. */ private static class SerializedForm extends ImmutableMap.SerializedForm { private final Comparator comparator; @SuppressWarnings("unchecked") SerializedForm(ImmutableSortedMap sortedMap) { super(sortedMap); comparator = (Comparator) sortedMap.comparator(); } @Override Object readResolve() { Builder builder = new Builder(comparator); return createMap(builder); } private static final long serialVersionUID = 0; } @Override Object writeReplace() { return new SerializedForm(this); } // This class is never actually serialized directly, but we have to make the // warning go away (and suppressing would suppress for all nested classes too) private static final long serialVersionUID = 0; }