com.google.common.collect.ImmutableSortedMap Maven / Gradle / Ivy
/*
* 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.Collection;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
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,
Collection> entries) {
if (entries.isEmpty()) {
return emptyMap(comparator);
}
ImmutableList.Builder keyBuilder = ImmutableList.builder();
ImmutableList.Builder valueBuilder = ImmutableList.builder();
for (Entry entry : entries) {
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
*/
public static , V> ImmutableSortedMap
of(K k1, V v1, K k2, V v2) {
return new Builder(Ordering.natural())
.put(k1, v1).put(k2, v2).build();
}
/**
* 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
*/
public static , V> ImmutableSortedMap
of(K k1, V v1, K k2, V v2, K k3, V v3) {
return new Builder(Ordering.natural())
.put(k1, v1).put(k2, v2).put(k3, v3).build();
}
/**
* 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
*/
public static , V> ImmutableSortedMap
of(K k1, V v1, K k2, V v2, K k3, V v3, K k4, V v4) {
return new Builder(Ordering.natural())
.put(k1, v1).put(k2, v2).put(k3, v3).put(k4, v4).build();
}
/**
* 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
*/
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 new Builder(Ordering.natural())
.put(k1, v1).put(k2, v2).put(k3, v3).put(k4, v4).put(k5, v5).build();
}
/**
* 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]);
for (int i = 0; i < entries.length; i++) {
Entry entry = entries[i];
entries[i] = entryOf(entry.getKey(), entry.getValue());
}
List> list = Arrays.asList(entries);
if (!sameComparator) {
sortEntries(list, comparator);
validateEntries(list, comparator);
}
return fromSortedEntries(comparator, list);
}
private static void sortEntries(
List> entries, final Comparator comparator) {
Comparator> entryComparator = new Comparator>() {
@Override public int compare(Entry entry1, Entry entry2) {
return comparator.compare(entry1.getKey(), entry2.getKey());
}
};
Collections.sort(entries, entryComparator);
}
private static void validateEntries(List> entries,
Comparator comparator) {
for (int i = 1; i < entries.size(); i++) {
if (comparator.compare(
entries.get(i - 1).getKey(), entries.get(i).getKey()) == 0) {
throw new IllegalArgumentException(
"Duplicate keys in mappings " + entries.get(i - 1) + " and "
+ entries.get(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.
*
* Note: the type parameter {@code K} extends {@code Comparable} rather
* than {@code Comparable} as a workaround for javac bug
* 6468354.
*/
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.
*
* Note: the type parameter {@code K} extends {@code Comparable} rather
* than {@code Comparable} as a workaround for javac bug
* 6468354.
*/
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}.
*/
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) {
entries.add(entryOf(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) {
for (Entry entry : map.entrySet()) {
put(entry.getKey(), entry.getValue());
}
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() {
sortEntries(entries, comparator);
validateEntries(entries, comparator);
return fromSortedEntries(comparator, 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);
}
@Override
public final Entry pollFirstEntry() {
throw new UnsupportedOperationException();
}
@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