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/*
* Copyright (C) 2007 Google Inc.
*
* 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 com.google.common.base.Function;
import com.google.common.base.Nullable;
import static com.google.common.base.Preconditions.checkNotNull;
import static com.google.common.base.Preconditions.checkState;
import com.google.common.base.Supplier;
import java.io.Serializable;
import java.util.AbstractMap;
import java.util.AbstractSet;
import java.util.Collection;
import java.util.Collections;
import java.util.Comparator;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.NoSuchElementException;
import java.util.Set;
import java.util.SortedSet;
/**
* Provides static methods acting on or generating a {@code Multimap}.
*
* @author Jared Levy
* @author Robert Konigsberg
* @author Mike Bostock
*/
public final class Multimaps {
private static final ListMultimap EMPTY_LIST_MULTIMAP
= new ImmutableMultimapBuilder().getMultimap();
private Multimaps() {}
/**
* Creates an empty {@code HashMultimap} instance.
*
* @return a newly-created, initially-empty {@code HashMultimap}
*/
public static HashMultimap newHashMultimap() {
return new HashMultimap();
}
/**
* Creates a {@code HashMultimap} instance initialized with all elements from
* the supplied {@code Multimap}. If the supplied multimap contains duplicate
* key-value pairs, those duplicate pairs will only be stored once in the new
* multimap.
*
* @param multimap the multimap whose contents are copied to this multimap.
* @return a newly-created and initialized {@code HashMultimap}
*/
public static HashMultimap newHashMultimap(
Multimap multimap) {
return new HashMultimap(multimap);
}
/**
* Creates an empty {@code ArrayListMultimap} instance.
*
* @return a newly-created, initially-empty {@code ArrayListMultimap}
*/
public static ArrayListMultimap newArrayListMultimap() {
return new ArrayListMultimap();
}
/**
* Creates an {@code ArrayListMultimap} instance initialized with all elements
* from the supplied {@code Multimap}.
*
* @param multimap the multimap whose contents are copied to this multimap.
* @return a newly-created and initialized {@code ArrayListMultimap}
*/
public static ArrayListMultimap newArrayListMultimap(
Multimap multimap) {
return new ArrayListMultimap(multimap);
}
/**
* Creates an empty {@code LinkedHashMultimap} instance.
*
* @return a newly-created, initially-empty {@code LinkedHashMultimap}
*/
public static LinkedHashMultimap newLinkedHashMultimap() {
return new LinkedHashMultimap();
}
/**
* Creates a {@code LinkedHashMultimap} instance initialized with all elements
* from the supplied {@code Multimap}. If the supplied multimap contains
* duplicate key-value pairs, those duplicate pairs will only be stored once
* in the new multimap. The new multimap has the same
* {@link Multimap#entries()} iteration order as the input multimap, except
* for excluding duplicate mappings.
*
* @param multimap the multimap whose contents are copied to this multimap.
* @return a newly-created and initialized {@code LinkedHashMultimap}
*/
public static LinkedHashMultimap newLinkedHashMultimap(
Multimap multimap) {
return new LinkedHashMultimap(multimap);
}
/**
* Creates an empty {@code LinkedListMultimap} instance.
*
* @return a newly-created, initially-empty {@code LinkedListMultimap}
*/
public static LinkedListMultimap newLinkedListMultimap() {
return new LinkedListMultimap();
}
/**
* Creates a {@code LinkedListMultimap} instance initialized with all elements
* from the supplied {@code Multimap}. The new multimap has the same
* {@link Multimap#entries()} iteration order as the input multimap.
*
* @param multimap the multimap whose contents are copied to this multimap.
* @return a newly-created and initialized {@code LinkedListMultimap}
*/
public static LinkedListMultimap newLinkedListMultimap(
Multimap multimap) {
return new LinkedListMultimap(multimap);
}
/**
* Creates an empty {@code TreeMultimap} instance using the natural ordering
* of keys and values. If the supplied multimap contains duplicate key-value
* pairs, those duplicate pairs will only be stored once in the new multimap.
*
* @return a newly-created, initially-empty {@code TreeMultimap}
*/
@SuppressWarnings("unchecked") // allow ungenerified Comparable types
public static
TreeMultimap newTreeMultimap() {
return new TreeMultimap();
}
/**
* Constructs a {@code TreeMultimap} with the same mappings as the specified
* {@code Multimap}.
*
* If the supplied multimap is an instance of {@code TreeMultimap}, the
* supplied multimap's comparators are copied to the new instance.
*
*
If the supplied multimap is not an instance of {@code TreeMultimap}, the
* new multimap is ordered using the natural ordering of the key and value
* classes. The key and value classes must satisfy the {@link Comparable}
* interface.
*
* @param multimap the multimap whose contents are copied to this multimap.
* @return a newly-created and initialized {@code TreeMultimap}
*/
public static TreeMultimap newTreeMultimap(
Multimap multimap) {
return new TreeMultimap(multimap);
}
/**
* Creates an empty {@code TreeMultimap} instance using explicit comparators.
*
* @param keyComparator the comparator that determines the key ordering. If
* it's {@code null}, the natural ordering of the keys is used.
* @param valueComparator the comparator that determines the value ordering.
* If it's {@code null}, the natural ordering of the values is used.
* @return a newly-created, initially-empty {@code TreeMultimap}
*/
public static TreeMultimap newTreeMultimap(
@Nullable Comparator keyComparator,
@Nullable Comparator valueComparator) {
return new TreeMultimap(keyComparator, valueComparator);
}
/**
* Creates a {@code TreeMultimap} instance using explicit comparators,
* initialized with all elements from the supplied {@code Multimap}.
*
* @param multimap the multimap whose contents are copied to this multimap.
* @return a newly-created and initialized {@code TreeMultimap}
*/
public static TreeMultimap newTreeMultimap(
@Nullable Comparator keyComparator,
@Nullable Comparator valueComparator,
Multimap multimap) {
return new TreeMultimap(keyComparator, valueComparator, multimap);
}
/**
* Creates a new {@code Multimap} that uses the provided map and factory. It
* can generate a multimap based on arbitrary {@link Map} and
* {@link Collection} classes.
*
* The {@code factory}-generated and {@code map} classes determine the
* multimap iteration order. They also specify the behavior of the
* {@code equals}, {@code hashCode}, and {@code toString} methods for the
* multimap and its returned views. However, the multimaps's {@code get}
* method returns instances of a different class than {@code factory.get()}
* does.
*
*
Call this method only when the simpler methods
* {@link #newArrayListMultimap()}, {@link #newHashMultimap()},
* {@link #newLinkedHashMultimap()}, {@link #newLinkedListMultimap()}, and
* {@link #newTreeMultimap()} won't suffice.
*
* @param map place to store the mapping from each key to its corresponding
* values
* @param factory supplier of new empty collections that will each hold all
* values for a given key
* @throws IllegalArgumentException if {@code map} is not empty
*/
public static Multimap newMultimap(Map> map,
final Supplier> factory) {
return new StandardMultimap(map) {
@Override protected Collection createCollection() {
return factory.get();
}
};
}
/**
* Creates a new {@code ListMultimap} that uses the provided map and factory.
* It can generate a multimap based on arbitrary {@link Map} and {@link List}
* classes.
*
* The {@code factory}-generated and {@code map} classes determine the
* multimap iteration order. They also specify the behavior of the
* {@code equals}, {@code hashCode}, and {@code toString} methods for the
* multimap and its returned views. However, the multimaps's {@code get}
* method returns instances of a different class than {@code factory.get()}
* does.
*
*
Call this method only when the simpler methods
* {@link #newArrayListMultimap()} and {@link #newLinkedListMultimap()} won't
* suffice.
*
* @param map place to store the mapping from each key to its corresponding
* values
* @param factory supplier of new empty lists that will each hold all values
* for a given key
* @throws IllegalArgumentException if {@code map} is not empty
*/
public static ListMultimap newListMultimap(
Map> map, final Supplier> factory) {
return new StandardListMultimap(map) {
@Override protected List createCollection() {
return factory.get();
}
};
}
/**
* Creates a new {@code SetMultimap} that uses the provided map and factory.
* It can generate a multimap based on arbitrary {@link Map} and {@link Set}
* classes.
*
* The {@code factory}-generated and {@code map} classes determine the
* multimap iteration order. They also specify the behavior of the
* {@code equals}, {@code hashCode}, and {@code toString} methods for the
* multimap and its returned views. However, the multimaps's {@code get}
* method returns instances of a different class than {@code factory.get()}
* does.
*
*
Call this method only when the simpler methods
* {@link #newHashMultimap()}, {@link #newLinkedHashMultimap()}, and
* {@link #newTreeMultimap()} won't suffice.
*
* @param map place to store the mapping from each key to its corresponding
* values
* @param factory supplier of new empty sets that will each hold all values
* for a given key
* @throws IllegalArgumentException if {@code map} is not empty
*/
public static SetMultimap newSetMultimap(
Map> map, final Supplier> factory) {
return new StandardSetMultimap(map) {
@Override protected Set createCollection() {
return factory.get();
}
};
}
/**
* Creates a new {@code SortedSetMultimap} that uses the provided map and
* factory. It can generate a multimap based on arbitrary {@link Map} and
* {@link SortedSet} classes.
*
* The {@code factory}-generated and {@code map} classes determine the
* multimap iteration order. They also specify the behavior of the
* {@code equals}, {@code hashCode}, and {@code toString} methods for the
* multimap and its returned views. However, the multimaps's {@code get}
* method returns instances of a different class than {@code factory.get()}
* does.
*
*
Call this method only when the simpler method {@link #newTreeMultimap()}
* won't suffice.
*
* @param map place to store the mapping from each key to its corresponding
* values
* @param factory supplier of new empty sorted sets that will each hold
* all values for a given key
* @throws IllegalArgumentException if {@code map} is not empty
*/
public static SortedSetMultimap newSortedSetMultimap(
Map> map,
final Supplier> factory) {
final Comparator valueComparator = factory.get().comparator();
return new StandardSortedSetMultimap(map) {
@Override protected SortedSet createCollection() {
return factory.get();
}
public Comparator valueComparator() {
return valueComparator;
}
};
}
/**
* Creates a {@code HashMultimap} that's the inverse of the provided multimap.
* If the input multimap includes the mapping from a key to a value, the
* returned multimap contains a mapping from the value to the key.
*
* If the input multimap has duplicate key-value mappings, the returned
* multimap includes the inverse mapping once.
*
*
The returned multimap is modifiable. Updating it will not affect the
* input multimap, and vice versa.
*
* @param multimap the multimap to invert
* @return the inverse of the input multimap
*/
public static HashMultimap inverseHashMultimap(
Multimap multimap) {
HashMultimap inverse = new HashMultimap();
addInverse(inverse, multimap);
return inverse;
}
/**
* Creates an {@code ArrayListMultimap} that's the inverse of the provided
* multimap. If the input multimap includes the mapping from a key to a value,
* the returned multimap contains a mapping from the value to the key.
*
* The returned multimap is modifiable. Updating it will not affect the
* input multimap, and vice versa.
*
* @param multimap the multimap to invert
* @return the inverse of the input multimap
*/
public static ArrayListMultimap inverseArrayListMultimap(
Multimap multimap) {
ArrayListMultimap inverse = new ArrayListMultimap();
addInverse(inverse, multimap);
return inverse;
}
/**
* Creates a {@code TreeMultimap} that's the inverse of the provided multimap.
* If the input multimap includes the mapping from a key to a value, the
* returned multimap contains a mapping from the value to the key. The
* returned multimap follows the natural ordering of its keys and values.
*
* If the input multimap has duplicate key-value mappings, the returned
* multimap includes the inverse mapping once.
*
*
The returned multimap is modifiable. Updating it will not affect the
* input map, and vice versa. The returned multimap orders the keys and values
* according to their natural ordering.
*
* @param multimap the multimap to invert
* @return the inverse of the input multimap
*/
@SuppressWarnings("unchecked") // allow ungenerified Comparable types
public static TreeMultimap
inverseTreeMultimap(Multimap multimap) {
TreeMultimap inverse = new TreeMultimap();
addInverse(inverse, multimap);
return inverse;
}
/** Inverts a multimap's entries and puts them in the inverse multimap. */
private static void addInverse(Multimap inverse,
Multimap multimap) {
for (Map.Entry entry : multimap.entries()) {
inverse.put(entry.getValue(), entry.getKey());
}
}
/**
* Returns a synchronized (thread-safe) multimap backed by the specified
* multimap. In order to guarantee serial access, it is critical that
* all access to the backing multimap is accomplished through the
* returned multimap.
*
* It is imperative that the user manually synchronize on the returned map
* when accessing any of its collection views:
*
*
Multimap<K,V> m = Multimaps.synchronizedMultimap(
* new HashMultimap<K,V>());
* ...
* Set<K> s = m.keySet(); // Needn't be in synchronized block
* ...
* synchronized (m) { // Synchronizing on m, not s!
* Iterator<K> i = s.iterator(); // Must be in synchronized block
* while (i.hasNext()) {
* foo(i.next());
* }
* }
*
* Failure to follow this advice may result in non-deterministic behavior.
*
* Note that the generated multimap's {@link Multimap#removeAll} and
* {@link Multimap#replaceValues} methods return collections that aren't
* synchronized.
*
* @param multimap the multimap to be wrapped in a synchronized view
* @return a synchronized view of the specified multimap
*/
public static Multimap synchronizedMultimap(
Multimap multimap) {
return Synchronized.multimap(multimap, null);
}
/**
* Returns an unmodifiable view of the specified multimap. Query operations on
* the returned multimap "read through" to the specified multimap, and
* attempts to modify the returned multimap, either directly or through the
* multimap's views, result in an {@code UnsupportedOperationException}.
*
* Note that the generated multimap's {@link Multimap#removeAll} and
* {@link Multimap#replaceValues} methods return collections that are
* modifiable.
*
* @param delegate the multimap for which an unmodifiable view is to be
* returned
* @return an unmodifiable view of the specified multimap
*/
public static Multimap unmodifiableMultimap(
Multimap delegate) {
return new UnmodifiableMultimap(delegate);
}
private static class UnmodifiableMultimap
extends ForwardingMultimap {
private static final long serialVersionUID = 0;
transient volatile Collection> entries;
transient volatile Multiset keys;
transient volatile Set keySet;
transient volatile Collection values;
transient volatile Map> map;
UnmodifiableMultimap(final Multimap delegate) {
super(delegate);
}
@Override public void clear() {
throw new UnsupportedOperationException();
}
@Override public Map> asMap() {
if (map == null) {
final Map> unmodifiableMap
= Collections.unmodifiableMap(delegate().asMap());
map = new ForwardingMap>(unmodifiableMap) {
@SuppressWarnings("hiding")
volatile Collection> values;
volatile Set>> entrySet;
@Override public Set>> entrySet() {
if (entrySet == null) {
entrySet = unmodifiableAsMapEntries(super.entrySet());
}
return entrySet;
}
@Override public Collection get(Object key) {
Collection collection = super.get(key);
return (collection == null)
? null : unmodifiableValueCollection(collection);
}
@Override public Collection> values() {
if (values == null) {
values = new UnmodifiableAsMapValues(super.values());
}
return values;
}
@Override public boolean containsValue(Object o) {
return values().contains(o);
}
};
}
return map;
}
@Override public Collection> entries() {
if (entries == null) {
entries = unmodifiableEntries(super.entries());
}
return entries;
}
@Override public Collection get(K key) {
return unmodifiableValueCollection(super.get(key));
}
@Override public Multiset keys() {
if (keys == null) {
keys = Multisets.unmodifiableMultiset(super.keys());
}
return keys;
}
@Override public Set keySet() {
if (keySet == null) {
keySet = Collections.unmodifiableSet(super.keySet());
}
return keySet;
}
@Override @SuppressWarnings("unused")
public boolean put(K key, V value) {
throw new UnsupportedOperationException();
}
@Override @SuppressWarnings("unused")
public void putAll(K key,
@SuppressWarnings("hiding") Iterable values) {
throw new UnsupportedOperationException();
}
@Override @SuppressWarnings("unused")
public void putAll(Multimap multimap) {
throw new UnsupportedOperationException();
}
@Override @SuppressWarnings("unused")
public boolean remove(Object key, Object value) {
throw new UnsupportedOperationException();
}
@Override @SuppressWarnings("unused")
public Collection removeAll(Object key) {
throw new UnsupportedOperationException();
}
@Override @SuppressWarnings("unused")
public Collection replaceValues(K key,
@SuppressWarnings("hiding") Iterable values) {
throw new UnsupportedOperationException();
}
@Override public Collection values() {
if (values == null) {
values = Collections.unmodifiableCollection(super.values());
}
return values;
}
}
private static class UnmodifiableAsMapValues
extends NonSerializableForwardingCollection> {
UnmodifiableAsMapValues(Collection> delegate) {
super(Collections.unmodifiableCollection(delegate));
}
@Override public Iterator> iterator() {
final Iterator> iterator = super.iterator();
return new Iterator>() {
public boolean hasNext() {
return iterator.hasNext();
}
public Collection next() {
return unmodifiableValueCollection(iterator.next());
}
public void remove() {
throw new UnsupportedOperationException();
}
};
}
@Override public Object[] toArray() {
return ForwardingCollection.toArrayImpl(this);
}
@Override public T[] toArray(T[] array) {
return ForwardingCollection.toArrayImpl(this, array);
}
@Override public boolean contains(Object o) {
return ForwardingCollection.containsImpl(this, o);
}
@Override public boolean containsAll(Collection c) {
return ForwardingCollection.containsAllImpl(this, c);
}
}
private static class UnmodifiableListMultimap
extends UnmodifiableMultimap implements ListMultimap {
UnmodifiableListMultimap(ListMultimap delegate) {
super(delegate);
}
@Override public ListMultimap delegate() {
return (ListMultimap) super.delegate();
}
@Override public List get(K key) {
return Collections.unmodifiableList(delegate().get(key));
}
@Override public List removeAll(Object key) {
throw new UnsupportedOperationException();
}
@Override public List replaceValues(
K key, @SuppressWarnings("hiding") Iterable values) {
throw new UnsupportedOperationException();
}
private static final long serialVersionUID = 0;
}
private static class UnmodifiableSetMultimap
extends UnmodifiableMultimap implements SetMultimap {
UnmodifiableSetMultimap(SetMultimap delegate) {
super(delegate);
}
@Override public SetMultimap delegate() {
return (SetMultimap) super.delegate();
}
@Override public Set get(K key) {
/*
* Note that this doesn't return a SortedSet when delegate is a
* SortedSetMultiset, unlike (SortedSet) super.get().
*/
return Collections.unmodifiableSet(delegate().get(key));
}
@Override public Set> entries() {
return Maps.unmodifiableEntrySet(delegate().entries());
}
@Override public Set removeAll(Object key) {
throw new UnsupportedOperationException();
}
@Override public Set replaceValues(
K key, @SuppressWarnings("hiding") Iterable values) {
throw new UnsupportedOperationException();
}
private static final long serialVersionUID = 0;
}
private static class UnmodifiableSortedSetMultimap
extends UnmodifiableSetMultimap implements SortedSetMultimap {
UnmodifiableSortedSetMultimap(SortedSetMultimap delegate) {
super(delegate);
}
@Override public SortedSetMultimap delegate() {
return (SortedSetMultimap) super.delegate();
}
@Override public SortedSet get(K key) {
return Collections.unmodifiableSortedSet(delegate().get(key));
}
@Override public SortedSet removeAll(Object key) {
throw new UnsupportedOperationException();
}
@Override public SortedSet replaceValues(
K key, @SuppressWarnings("hiding") Iterable values) {
throw new UnsupportedOperationException();
}
public Comparator valueComparator() {
return delegate().valueComparator();
}
private static final long serialVersionUID = 0;
}
/**
* Returns a synchronized (thread-safe) {@code SetMultimap} backed by the
* specified multimap.
*
* You must follow the warnings described in {@link #synchronizedMultimap}.
*
* @param multimap the multimap to be wrapped
* @return a synchronized view of the specified multimap
*/
public static SetMultimap synchronizedSetMultimap(
SetMultimap multimap) {
return Synchronized.setMultimap(multimap, null);
}
/**
* Returns an unmodifiable view of the specified {@code SetMultimap}. Query
* operations on the returned multimap "read through" to the specified
* multimap, and attempts to modify the returned multimap, either directly or
* through the multimap's views, result in an
* {@code UnsupportedOperationException}.
*
* Note that the generated multimap's {@link Multimap#removeAll} and
* {@link Multimap#replaceValues} methods return collections that are
* modifiable.
*
* @param delegate the multimap for which an unmodifiable view is to be
* returned
* @return an unmodifiable view of the specified multimap
*/
public static SetMultimap unmodifiableSetMultimap(
SetMultimap delegate) {
return new UnmodifiableSetMultimap(delegate);
}
/**
* Returns a synchronized (thread-safe) {@code SortedSetMultimap} backed by
* the specified multimap.
*
* You must follow the warnings described in {@link #synchronizedMultimap}.
*
* @param multimap the multimap to be wrapped
* @return a synchronized view of the specified multimap
*/
public static SortedSetMultimap
synchronizedSortedSetMultimap(SortedSetMultimap multimap) {
return Synchronized.sortedSetMultimap(multimap, null);
}
/**
* Returns an unmodifiable view of the specified {@code SortedSetMultimap}.
* Query operations on the returned multimap "read through" to the specified
* multimap, and attempts to modify the returned multimap, either directly or
* through the multimap's views, result in an
* {@code UnsupportedOperationException}.
*
* Note that the generated multimap's {@link Multimap#removeAll} and
* {@link Multimap#replaceValues} methods return collections that are
* modifiable.
*
* @param delegate the multimap for which an unmodifiable view is to be
* returned
* @return an unmodifiable view of the specified multimap
*/
public static SortedSetMultimap unmodifiableSortedSetMultimap(
SortedSetMultimap delegate) {
return new UnmodifiableSortedSetMultimap(delegate);
}
/**
* Returns a synchronized (thread-safe) {@code ListMultimap} backed by the
* specified multimap.
*
* You must follow the warnings described in {@link #synchronizedMultimap}.
*
* @param multimap the multimap to be wrapped
* @return a synchronized view of the specified multimap
*/
public static ListMultimap synchronizedListMultimap(
ListMultimap multimap) {
return Synchronized.listMultimap(multimap, null);
}
/**
* Returns an unmodifiable view of the specified {@code ListMultimap}. Query
* operations on the returned multimap "read through" to the specified
* multimap, and attempts to modify the returned multimap, either directly or
* through the multimap's views, result in an
* {@code UnsupportedOperationException}.
*
* Note that the generated multimap's {@link Multimap#removeAll} and
* {@link Multimap#replaceValues} methods return collections that are
* modifiable.
*
* @param delegate the multimap for which an unmodifiable view is to be
* returned
* @return an unmodifiable view of the specified multimap
*/
public static ListMultimap unmodifiableListMultimap(
ListMultimap delegate) {
return new UnmodifiableListMultimap(delegate);
}
/**
* Returns an unmodifiable view of the specified collection, preserving the
* interface for instances of {@code SortedSet}, {@code Set}, {@code List} and
* {@code Collection}, in that order of preference.
*
* @param collection the collection for which to return an unmodifiable view
* @return an unmodifiable view of the collection
*/
private static Collection unmodifiableValueCollection(
Collection collection) {
if (collection instanceof SortedSet) {
return Collections.unmodifiableSortedSet((SortedSet) collection);
} else if (collection instanceof Set) {
return Collections.unmodifiableSet((Set) collection);
} else if (collection instanceof List) {
return Collections.unmodifiableList((List) collection);
}
return Collections.unmodifiableCollection(collection);
}
/**
* Returns an unmodifiable view of the specified multimap {@code asMap} entry.
* The {@link Entry#setValue} operation throws an {@link
* UnsupportedOperationException}, and the collection returned by {@code
* getValue} is also an unmodifiable (type-preserving) view. This also has the
* side-effect of redefining equals to comply with the Map.Entry contract, and
* 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
*/
private static Map.Entry> unmodifiableAsMapEntry(
final Map.Entry> entry) {
checkNotNull(entry);
return new AbstractMapEntry>() {
@Override public K getKey() {
return entry.getKey();
}
@Override public Collection getValue() {
return unmodifiableValueCollection(entry.getValue());
}
};
}
/**
* Returns an unmodifiable view of the specified collection of entries. The
* {@link Entry#setValue} operation throws an {@link
* UnsupportedOperationException}. If the specified collection is a {@code
* Set}, the returned collection is also a {@code Set}.
*
* @param entries the entries for which to return an unmodifiable view
* @return an unmodifiable view of the entries
*/
private static Collection> unmodifiableEntries(
Collection> entries) {
if (entries instanceof Set) {
return Maps.unmodifiableEntrySet((Set>) entries);
}
return new Maps.UnmodifiableEntries(
Collections.unmodifiableCollection(entries));
}
/**
* Returns an unmodifiable view of the specified set of {@code asMap} entries.
* The {@link Entry#setValue} operation throws an {@link
* UnsupportedOperationException}, as do any operations that attempt to modify
* the returned collection.
*
* @param asMapEntries the {@code asMap} entries for which to return an
* unmodifiable view
* @return an unmodifiable view of the collection entries
*/
private static Set>> unmodifiableAsMapEntries(
Set>> asMapEntries) {
return new UnmodifiableAsMapEntries(
Collections.unmodifiableSet(asMapEntries));
}
/** @see Multimaps#unmodifiableAsMapEntries */
static class UnmodifiableAsMapEntries
extends NonSerializableForwardingSet>> {
UnmodifiableAsMapEntries(
Set>> asMapEntries) {
super(asMapEntries);
}
@Override public Iterator>> iterator() {
return new ForwardingIterator>>(super.iterator()) {
@Override public Entry> next() {
return unmodifiableAsMapEntry(super.next());
}
};
}
@Override public Object[] toArray() {
return ForwardingSet.toArrayImpl(this);
}
@Override public T[] toArray(T[] array) {
return ForwardingSet.toArrayImpl(this, array);
}
@Override public boolean contains(Object o) {
return Maps.containsEntryImpl(delegate(), o);
}
@Override public boolean containsAll(Collection c) {
return ForwardingSet.containsAllImpl(this, c);
}
@Override public boolean equals(Object o) {
return ForwardingSet.equalsImpl(this, o);
}
}
/**
* Returns a multimap view of the specified map. The multimap is backed by the
* map, so changes to the map are reflected in the multimap, and vice versa.
* If the map is modified while an iteration over one of the multimap's
* collection views is in progress (except through the iterator's own {@code
* remove} operation, or through the {@code setValue} operation on a map entry
* returned by the iterator), the results of the iteration are undefined.
*
* The multimap supports mapping removal, which removes the corresponding
* mapping from the map. It does not support any operations which might add
* mappings, such as {@code put}, {@code putAll} or {@code replaceValues}.
*
*
The returned multimap will be serializable if the specified map is
* serializable.
*
* @param map the backing map for the returned multimap view
*/
public static SetMultimap forMap(Map map) {
return new MapMultimap(map);
}
/** @see Multimaps#forMap */
private static class MapMultimap
implements SetMultimap, Serializable {
final Map map;
transient volatile Map> asMap;
MapMultimap(Map map) {
this.map = checkNotNull(map);
}
public int size() {
return map.size();
}
public boolean isEmpty() {
return map.isEmpty();
}
public boolean containsKey(Object key) {
return map.containsKey(key);
}
public boolean containsValue(Object value) {
return map.containsValue(value);
}
public boolean containsEntry(Object key, Object value) {
return map.entrySet().contains(Maps.immutableEntry(key, value));
}
public Set get(final K key) {
return new AbstractSet() {
@Override public Iterator iterator() {
return new Iterator() {
int i;
public boolean hasNext() {
return (i == 0) && map.containsKey(key);
}
public V next() {
if (!hasNext()) {
throw new NoSuchElementException();
}
i++;
return map.get(key);
}
public void remove() {
checkState(i == 1);
i = -1;
map.remove(key);
}
};
}
@Override public int size() {
return map.containsKey(key) ? 1 : 0;
}
};
}
public boolean put(K key, V value) {
throw new UnsupportedOperationException();
}
public void putAll(K key, Iterable values) {
throw new UnsupportedOperationException();
}
public void putAll(Multimap multimap) {
throw new UnsupportedOperationException();
}
public Set replaceValues(K key, Iterable values) {
throw new UnsupportedOperationException();
}
public boolean remove(Object key, Object value) {
return map.entrySet().remove(Maps.immutableEntry(key, value));
}
public Set removeAll(Object key) {
Set values = new HashSet(2);
if (!map.containsKey(key)) {
return values;
}
values.add(map.remove(key));
return values;
}
public void clear() {
map.clear();
}
public Set keySet() {
return map.keySet();
}
public Multiset keys() {
return Multisets.forSet(map.keySet());
}
public Collection values() {
return map.values();
}
public Set> entries() {
return map.entrySet();
}
public Map> asMap() {
if (asMap == null) {
asMap = new AsMap();
}
return asMap;
}
@Override public boolean equals(Object o) {
if (this == o) {
return true;
}
if (!(o instanceof SetMultimap)) {
return false;
}
Multimap m = (Multimap) o;
if (map.size() != m.size()) {
return false;
}
for (Entry e : map.entrySet()) {
if (!m.containsEntry(e.getKey(), e.getValue())) {
return false;
}
}
return true;
}
@Override public int hashCode() {
return map.hashCode();
}
@Override public String toString() {
StringBuilder builder = new StringBuilder();
builder.append('{');
for (Entry e : map.entrySet()) {
builder.append(e.getKey()).append("=[")
.append(e.getValue()).append("], ");
}
if (builder.length() > 1) {
builder.setLength(builder.length() - 2); // delete last comma and space
}
builder.append('}');
return builder.toString();
}
/** @see MapMultimap#asMap */
class AsMapEntries extends AbstractSet>> {
@Override public int size() {
return map.size();
}
@Override public Iterator>> iterator() {
return new Iterator>>() {
final Iterator keys = map.keySet().iterator();
public boolean hasNext() {
return keys.hasNext();
}
public Entry> next() {
final K key = keys.next();
return new AbstractMapEntry>() {
@Override public K getKey() {
return key;
}
@Override public Collection getValue() {
return get(key);
}
};
}
public void remove() {
keys.remove();
}
};
}
@Override public boolean contains(Object o) {
if (!(o instanceof Entry)) {
return false;
}
Entry entry = (Entry) o;
if (!(entry.getValue() instanceof Set)) {
return false;
}
Set set = (Set) entry.getValue();
return (set.size() == 1)
&& containsEntry(entry.getKey(), set.iterator().next());
}
@Override public boolean remove(Object o) {
if (!(o instanceof Entry)) {
return false;
}
Entry entry = (Entry) o;
if (!(entry.getValue() instanceof Set)) {
return false;
}
Set set = (Set) entry.getValue();
return (set.size() == 1)
&& map.entrySet().remove(
Maps.immutableEntry(entry.getKey(), set.iterator().next()));
}
}
/** @see MapMultimap#asMap */
class AsMap extends AbstractMap> {
private volatile Set>> entries;
@Override public Set>> entrySet() {
if (entries == null) {
entries = new AsMapEntries();
}
return entries;
}
// The following methods are included for performance.
@Override public boolean containsKey(Object key) {
return map.containsKey(key);
}
@SuppressWarnings("unchecked")
@Override public Collection get(Object key) {
Collection collection = MapMultimap.this.get((K) key);
return collection.isEmpty() ? null : collection;
}
@Override public Collection remove(Object key) {
Collection collection = removeAll(key);
return collection.isEmpty() ? null : collection;
}
}
private static final long serialVersionUID = 7845222491160860175L;
}
/**
* Returns the immutable empty multimap.
*/
@SuppressWarnings("unchecked")
public static ListMultimap