/*
* 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.checkNotNull;
import static com.google.common.collect.CollectPreconditions.checkNonnegative;
import static com.google.common.collect.CollectPreconditions.checkRemove;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;
import java.util.AbstractCollection;
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;
import javax.annotation.Nullable;
import com.google.common.annotations.Beta;
import com.google.common.annotations.GwtCompatible;
import com.google.common.annotations.GwtIncompatible;
import com.google.common.base.Function;
import com.google.common.base.Predicate;
import com.google.common.base.Predicates;
import com.google.common.base.Supplier;
import com.google.common.collect.Maps.EntryTransformer;
/**
* Provides static methods acting on or generating a {@code Multimap}.
*
* <p>
* See the Guava User Guide article on <a href=
* "http://code.google.com/p/guava-libraries/wiki/CollectionUtilitiesExplained#Multimaps">
* {@code Multimaps}</a>.
*
* @author Jared Levy
* @author Robert Konigsberg
* @author Mike Bostock
* @author Louis Wasserman
* @since 2.0 (imported from Google Collections Library)
*/
@GwtCompatible(emulated = true)
public final class Multimaps {
private Multimaps() {
}
/**
* Creates a new {@code Multimap} backed by {@code map}, whose internal value
* collections are generated by {@code factory}.
*
* <b>Warning: do not use</b> this method when the collections returned by
* {@code factory} implement either {@link List} or {@code Set}! Use the more
* specific method {@link #newListMultimap}, {@link #newSetMultimap} or
* {@link #newSortedSetMultimap} instead, to avoid very surprising behavior from
* {@link Multimap#equals}.
*
* <p>
* 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 multimap's {@code get} method returns instances
* of a different class than {@code factory.get()} does.
*
* <p>
* The multimap is serializable if {@code map}, {@code factory}, the collections
* generated by {@code factory}, and the multimap contents are all serializable.
*
* <p>
* The multimap is not threadsafe when any concurrent operations update the
* multimap, even if {@code map} and the instances generated by {@code factory}
* are. Concurrent read operations will work correctly. To allow concurrent
* update operations, wrap the multimap with a call to
* {@link #synchronizedMultimap}.
*
* <p>
* Call this method only when the simpler methods
* {@link ArrayListMultimap#create()}, {@link HashMultimap#create()},
* {@link LinkedHashMultimap#create()}, {@link LinkedListMultimap#create()},
* {@link TreeMultimap#create()}, and
* {@link TreeMultimap#create(Comparator, Comparator)} won't suffice.
*
* <p>
* Note: the multimap assumes complete ownership over of {@code map} and the
* collections returned by {@code factory}. Those objects should not be manually
* updated and they should not use soft, weak, or phantom references.
*
* @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 <K, V> Multimap<K, V> newMultimap(Map<K, Collection<V>> map,
final Supplier<? extends Collection<V>> factory) {
return new CustomMultimap<K, V>(map, factory);
}
private static class CustomMultimap<K, V> extends AbstractMapBasedMultimap<K, V> {
transient Supplier<? extends Collection<V>> factory;
CustomMultimap(Map<K, Collection<V>> map, Supplier<? extends Collection<V>> factory) {
super(map);
this.factory = checkNotNull(factory);
}
@Override
protected Collection<V> createCollection() {
return factory.get();
}
// can't use Serialization writeMultimap and populateMultimap methods since
// there's no way to generate the empty backing map.
/** @serialData the factory and the backing map */
@GwtIncompatible("java.io.ObjectOutputStream")
private void writeObject(ObjectOutputStream stream) throws IOException {
stream.defaultWriteObject();
stream.writeObject(factory);
stream.writeObject(backingMap());
}
@GwtIncompatible("java.io.ObjectInputStream")
@SuppressWarnings("unchecked") // reading data stored by writeObject
private void readObject(ObjectInputStream stream) throws IOException, ClassNotFoundException {
stream.defaultReadObject();
factory = (Supplier<? extends Collection<V>>) stream.readObject();
Map<K, Collection<V>> map = (Map<K, Collection<V>>) stream.readObject();
setMap(map);
}
@GwtIncompatible("java serialization not supported")
private static final long serialVersionUID = 0;
}
/**
* 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.
*
* <p>
* 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. The multimap's {@code get}, {@code
* removeAll}, and {@code replaceValues} methods return {@code RandomAccess}
* lists if the factory does. However, the multimap's {@code get} method returns
* instances of a different class than does {@code factory.get()}.
*
* <p>
* The multimap is serializable if {@code map}, {@code factory}, the lists
* generated by {@code factory}, and the multimap contents are all serializable.
*
* <p>
* The multimap is not threadsafe when any concurrent operations update the
* multimap, even if {@code map} and the instances generated by {@code factory}
* are. Concurrent read operations will work correctly. To allow concurrent
* update operations, wrap the multimap with a call to
* {@link #synchronizedListMultimap}.
*
* <p>
* Call this method only when the simpler methods
* {@link ArrayListMultimap#create()} and {@link LinkedListMultimap#create()}
* won't suffice.
*
* <p>
* Note: the multimap assumes complete ownership over of {@code map} and the
* lists returned by {@code factory}. Those objects should not be manually
* updated, they should be empty when provided, and they should not use soft,
* weak, or phantom references.
*
* @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 <K, V> ListMultimap<K, V> newListMultimap(Map<K, Collection<V>> map,
final Supplier<? extends List<V>> factory) {
return new CustomListMultimap<K, V>(map, factory);
}
private static class CustomListMultimap<K, V> extends AbstractListMultimap<K, V> {
transient Supplier<? extends List<V>> factory;
CustomListMultimap(Map<K, Collection<V>> map, Supplier<? extends List<V>> factory) {
super(map);
this.factory = checkNotNull(factory);
}
@Override
protected List<V> createCollection() {
return factory.get();
}
/** @serialData the factory and the backing map */
@GwtIncompatible("java.io.ObjectOutputStream")
private void writeObject(ObjectOutputStream stream) throws IOException {
stream.defaultWriteObject();
stream.writeObject(factory);
stream.writeObject(backingMap());
}
@GwtIncompatible("java.io.ObjectInputStream")
@SuppressWarnings("unchecked") // reading data stored by writeObject
private void readObject(ObjectInputStream stream) throws IOException, ClassNotFoundException {
stream.defaultReadObject();
factory = (Supplier<? extends List<V>>) stream.readObject();
Map<K, Collection<V>> map = (Map<K, Collection<V>>) stream.readObject();
setMap(map);
}
@GwtIncompatible("java serialization not supported")
private static final long serialVersionUID = 0;
}
/**
* 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.
*
* <p>
* 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 multimap's {@code get} method returns instances
* of a different class than {@code factory.get()} does.
*
* <p>
* The multimap is serializable if {@code map}, {@code factory}, the sets
* generated by {@code factory}, and the multimap contents are all serializable.
*
* <p>
* The multimap is not threadsafe when any concurrent operations update the
* multimap, even if {@code map} and the instances generated by {@code factory}
* are. Concurrent read operations will work correctly. To allow concurrent
* update operations, wrap the multimap with a call to
* {@link #synchronizedSetMultimap}.
*
* <p>
* Call this method only when the simpler methods {@link HashMultimap#create()},
* {@link LinkedHashMultimap#create()}, {@link TreeMultimap#create()}, and
* {@link TreeMultimap#create(Comparator, Comparator)} won't suffice.
*
* <p>
* Note: the multimap assumes complete ownership over of {@code map} and the
* sets returned by {@code factory}. Those objects should not be manually
* updated and they should not use soft, weak, or phantom references.
*
* @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 <K, V> SetMultimap<K, V> newSetMultimap(Map<K, Collection<V>> map,
final Supplier<? extends Set<V>> factory) {
return new CustomSetMultimap<K, V>(map, factory);
}
private static class CustomSetMultimap<K, V> extends AbstractSetMultimap<K, V> {
transient Supplier<? extends Set<V>> factory;
CustomSetMultimap(Map<K, Collection<V>> map, Supplier<? extends Set<V>> factory) {
super(map);
this.factory = checkNotNull(factory);
}
@Override
protected Set<V> createCollection() {
return factory.get();
}
/** @serialData the factory and the backing map */
@GwtIncompatible("java.io.ObjectOutputStream")
private void writeObject(ObjectOutputStream stream) throws IOException {
stream.defaultWriteObject();
stream.writeObject(factory);
stream.writeObject(backingMap());
}
@GwtIncompatible("java.io.ObjectInputStream")
@SuppressWarnings("unchecked") // reading data stored by writeObject
private void readObject(ObjectInputStream stream) throws IOException, ClassNotFoundException {
stream.defaultReadObject();
factory = (Supplier<? extends Set<V>>) stream.readObject();
Map<K, Collection<V>> map = (Map<K, Collection<V>>) stream.readObject();
setMap(map);
}
@GwtIncompatible("not needed in emulated source")
private static final long serialVersionUID = 0;
}
/**
* 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.
*
* <p>
* 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 multimap's {@code get} method returns instances
* of a different class than {@code factory.get()} does.
*
* <p>
* The multimap is serializable if {@code map}, {@code factory}, the sets
* generated by {@code factory}, and the multimap contents are all serializable.
*
* <p>
* The multimap is not threadsafe when any concurrent operations update the
* multimap, even if {@code map} and the instances generated by {@code factory}
* are. Concurrent read operations will work correctly. To allow concurrent
* update operations, wrap the multimap with a call to
* {@link #synchronizedSortedSetMultimap}.
*
* <p>
* Call this method only when the simpler methods {@link TreeMultimap#create()}
* and {@link TreeMultimap#create(Comparator, Comparator)} won't suffice.
*
* <p>
* Note: the multimap assumes complete ownership over of {@code map} and the
* sets returned by {@code factory}. Those objects should not be manually
* updated and they should not use soft, weak, or phantom references.
*
* @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 <K, V> SortedSetMultimap<K, V> newSortedSetMultimap(Map<K, Collection<V>> map,
final Supplier<? extends SortedSet<V>> factory) {
return new CustomSortedSetMultimap<K, V>(map, factory);
}
private static class CustomSortedSetMultimap<K, V> extends AbstractSortedSetMultimap<K, V> {
transient Supplier<? extends SortedSet<V>> factory;
transient Comparator<? super V> valueComparator;
CustomSortedSetMultimap(Map<K, Collection<V>> map, Supplier<? extends SortedSet<V>> factory) {
super(map);
this.factory = checkNotNull(factory);
valueComparator = factory.get().comparator();
}
@Override
protected SortedSet<V> createCollection() {
return factory.get();
}
@Override
public Comparator<? super V> valueComparator() {
return valueComparator;
}
/** @serialData the factory and the backing map */
@GwtIncompatible("java.io.ObjectOutputStream")
private void writeObject(ObjectOutputStream stream) throws IOException {
stream.defaultWriteObject();
stream.writeObject(factory);
stream.writeObject(backingMap());
}
@GwtIncompatible("java.io.ObjectInputStream")
@SuppressWarnings("unchecked") // reading data stored by writeObject
private void readObject(ObjectInputStream stream) throws IOException, ClassNotFoundException {
stream.defaultReadObject();
factory = (Supplier<? extends SortedSet<V>>) stream.readObject();
valueComparator = factory.get().comparator();
Map<K, Collection<V>> map = (Map<K, Collection<V>>) stream.readObject();
setMap(map);
}
@GwtIncompatible("not needed in emulated source")
private static final long serialVersionUID = 0;
}
/**
* Copies each key-value mapping in {@code source} into {@code dest}, with its
* key and value reversed.
*
* <p>
* If {@code source} is an {@link ImmutableMultimap}, consider using
* {@link ImmutableMultimap#inverse} instead.
*
* @param source any multimap
* @param dest the multimap to copy into; usually empty
* @return {@code dest}
*/
public static <K, V, M extends Multimap<K, V>> M invertFrom(Multimap<? extends V, ? extends K> source, M dest) {
checkNotNull(dest);
for (Map.Entry<? extends V, ? extends K> entry : source.entries()) {
dest.put(entry.getValue(), entry.getKey());
}
return dest;
}
/**
* Returns a synchronized (thread-safe) multimap backed by the specified
* multimap. In order to guarantee serial access, it is critical that <b>all</b>
* access to the backing multimap is accomplished through the returned multimap.
*
* <p>
* It is imperative that the user manually synchronize on the returned multimap
* when accessing any of its collection views:
*
* <pre>
* {@code
*
* Multimap<K, V> multimap = Multimaps.synchronizedMultimap(
* HashMultimap.<K, V>create());
* ...
* Collection<V> values = multimap.get(key); // Needn't be in synchronized block
* ...
* synchronized (multimap) { // Synchronizing on multimap, not values!
* Iterator<V> i = values.iterator(); // Must be in synchronized block
* while (i.hasNext()) {
* foo(i.next());
* }
* }}
* </pre>
*
* <p>
* Failure to follow this advice may result in non-deterministic behavior.
*
* <p>
* Note that the generated multimap's {@link Multimap#removeAll} and
* {@link Multimap#replaceValues} methods return collections that aren't
* synchronized.
*
* <p>
* The returned multimap will be serializable if the specified multimap is
* serializable.
*
* @param multimap the multimap to be wrapped in a synchronized view
* @return a synchronized view of the specified multimap
*/
public static <K, V> Multimap<K, V> synchronizedMultimap(Multimap<K, V> 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}.
*
* <p>
* Note that the generated multimap's {@link Multimap#removeAll} and
* {@link Multimap#replaceValues} methods return collections that are
* modifiable.
*
* <p>
* The returned multimap will be serializable if the specified multimap is
* serializable.
*
* @param delegate the multimap for which an unmodifiable view is to be returned
* @return an unmodifiable view of the specified multimap
*/
public static <K, V> Multimap<K, V> unmodifiableMultimap(Multimap<K, V> delegate) {
if (delegate instanceof UnmodifiableMultimap || delegate instanceof ImmutableMultimap) {
return delegate;
}
return new UnmodifiableMultimap<K, V>(delegate);
}
/**
* Simply returns its argument.
*
* @deprecated no need to use this
* @since 10.0
*/
@Deprecated
public static <K, V> Multimap<K, V> unmodifiableMultimap(ImmutableMultimap<K, V> delegate) {
return checkNotNull(delegate);
}
private static class UnmodifiableMultimap<K, V> extends ForwardingMultimap<K, V> implements Serializable {
final Multimap<K, V> delegate;
transient Collection<Entry<K, V>> entries;
transient Multiset<K> keys;
transient Set<K> keySet;
transient Collection<V> values;
transient Map<K, Collection<V>> map;
UnmodifiableMultimap(final Multimap<K, V> delegate) {
this.delegate = checkNotNull(delegate);
}
@Override
protected Multimap<K, V> delegate() {
return delegate;
}
@Override
public void clear() {
throw new UnsupportedOperationException();
}
@Override
public Map<K, Collection<V>> asMap() {
Map<K, Collection<V>> result = map;
if (result == null) {
result = map = Collections.unmodifiableMap(
Maps.transformValues(delegate.asMap(), new Function<Collection<V>, Collection<V>>() {
@Override
public Collection<V> apply(Collection<V> collection) {
return unmodifiableValueCollection(collection);
}
}));
}
return result;
}
@Override
public Collection<Entry<K, V>> entries() {
Collection<Entry<K, V>> result = entries;
if (result == null) {
entries = result = unmodifiableEntries(delegate.entries());
}
return result;
}
@Override
public Collection<V> get(K key) {
return unmodifiableValueCollection(delegate.get(key));
}
@Override
public Multiset<K> keys() {
Multiset<K> result = keys;
if (result == null) {
keys = result = Multisets.unmodifiableMultiset(delegate.keys());
}
return result;
}
@Override
public Set<K> keySet() {
Set<K> result = keySet;
if (result == null) {
keySet = result = Collections.unmodifiableSet(delegate.keySet());
}
return result;
}
@Override
public boolean put(K key, V value) {
throw new UnsupportedOperationException();
}
@Override
public boolean putAll(K key, Iterable<? extends V> values) {
throw new UnsupportedOperationException();
}
@Override
public boolean putAll(Multimap<? extends K, ? extends V> multimap) {
throw new UnsupportedOperationException();
}
@Override
public boolean remove(Object key, Object value) {
throw new UnsupportedOperationException();
}
@Override
public Collection<V> removeAll(Object key) {
throw new UnsupportedOperationException();
}
@Override
public Collection<V> replaceValues(K key, Iterable<? extends V> values) {
throw new UnsupportedOperationException();
}
@Override
public Collection<V> values() {
Collection<V> result = values;
if (result == null) {
values = result = Collections.unmodifiableCollection(delegate.values());
}
return result;
}
private static final long serialVersionUID = 0;
}
private static class UnmodifiableListMultimap<K, V> extends UnmodifiableMultimap<K, V>
implements ListMultimap<K, V> {
UnmodifiableListMultimap(ListMultimap<K, V> delegate) {
super(delegate);
}
@Override
public ListMultimap<K, V> delegate() {
return (ListMultimap<K, V>) super.delegate();
}
@Override
public List<V> get(K key) {
return Collections.unmodifiableList(delegate().get(key));
}
@Override
public List<V> removeAll(Object key) {
throw new UnsupportedOperationException();
}
@Override
public List<V> replaceValues(K key, Iterable<? extends V> values) {
throw new UnsupportedOperationException();
}
private static final long serialVersionUID = 0;
}
private static class UnmodifiableSetMultimap<K, V> extends UnmodifiableMultimap<K, V> implements SetMultimap<K, V> {
UnmodifiableSetMultimap(SetMultimap<K, V> delegate) {
super(delegate);
}
@Override
public SetMultimap<K, V> delegate() {
return (SetMultimap<K, V>) super.delegate();
}
@Override
public Set<V> get(K key) {
/*
* Note that this doesn't return a SortedSet when delegate is a
* SortedSetMultiset, unlike (SortedSet<V>) super.get().
*/
return Collections.unmodifiableSet(delegate().get(key));
}
@Override
public Set<Map.Entry<K, V>> entries() {
return Maps.unmodifiableEntrySet(delegate().entries());
}
@Override
public Set<V> removeAll(Object key) {
throw new UnsupportedOperationException();
}
@Override
public Set<V> replaceValues(K key, Iterable<? extends V> values) {
throw new UnsupportedOperationException();
}
private static final long serialVersionUID = 0;
}
private static class UnmodifiableSortedSetMultimap<K, V> extends UnmodifiableSetMultimap<K, V>
implements SortedSetMultimap<K, V> {
UnmodifiableSortedSetMultimap(SortedSetMultimap<K, V> delegate) {
super(delegate);
}
@Override
public SortedSetMultimap<K, V> delegate() {
return (SortedSetMultimap<K, V>) super.delegate();
}
@Override
public SortedSet<V> get(K key) {
return Collections.unmodifiableSortedSet(delegate().get(key));
}
@Override
public SortedSet<V> removeAll(Object key) {
throw new UnsupportedOperationException();
}
@Override
public SortedSet<V> replaceValues(K key, Iterable<? extends V> values) {
throw new UnsupportedOperationException();
}
@Override
public Comparator<? super V> valueComparator() {
return delegate().valueComparator();
}
private static final long serialVersionUID = 0;
}
/**
* Returns a synchronized (thread-safe) {@code SetMultimap} backed by the
* specified multimap.
*
* <p>
* You must follow the warnings described in {@link #synchronizedMultimap}.
*
* <p>
* The returned multimap will be serializable if the specified multimap is
* serializable.
*
* @param multimap the multimap to be wrapped
* @return a synchronized view of the specified multimap
*/
public static <K, V> SetMultimap<K, V> synchronizedSetMultimap(SetMultimap<K, V> 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}.
*
* <p>
* Note that the generated multimap's {@link Multimap#removeAll} and
* {@link Multimap#replaceValues} methods return collections that are
* modifiable.
*
* <p>
* The returned multimap will be serializable if the specified multimap is
* serializable.
*
* @param delegate the multimap for which an unmodifiable view is to be returned
* @return an unmodifiable view of the specified multimap
*/
public static <K, V> SetMultimap<K, V> unmodifiableSetMultimap(SetMultimap<K, V> delegate) {
if (delegate instanceof UnmodifiableSetMultimap || delegate instanceof ImmutableSetMultimap) {
return delegate;
}
return new UnmodifiableSetMultimap<K, V>(delegate);
}
/**
* Simply returns its argument.
*
* @deprecated no need to use this
* @since 10.0
*/
@Deprecated
public static <K, V> SetMultimap<K, V> unmodifiableSetMultimap(ImmutableSetMultimap<K, V> delegate) {
return checkNotNull(delegate);
}
/**
* Returns a synchronized (thread-safe) {@code SortedSetMultimap} backed by the
* specified multimap.
*
* <p>
* You must follow the warnings described in {@link #synchronizedMultimap}.
*
* <p>
* The returned multimap will be serializable if the specified multimap is
* serializable.
*
* @param multimap the multimap to be wrapped
* @return a synchronized view of the specified multimap
*/
public static <K, V> SortedSetMultimap<K, V> synchronizedSortedSetMultimap(SortedSetMultimap<K, V> 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}.
*
* <p>
* Note that the generated multimap's {@link Multimap#removeAll} and
* {@link Multimap#replaceValues} methods return collections that are
* modifiable.
*
* <p>
* The returned multimap will be serializable if the specified multimap is
* serializable.
*
* @param delegate the multimap for which an unmodifiable view is to be returned
* @return an unmodifiable view of the specified multimap
*/
public static <K, V> SortedSetMultimap<K, V> unmodifiableSortedSetMultimap(SortedSetMultimap<K, V> delegate) {
if (delegate instanceof UnmodifiableSortedSetMultimap) {
return delegate;
}
return new UnmodifiableSortedSetMultimap<K, V>(delegate);
}
/**
* Returns a synchronized (thread-safe) {@code ListMultimap} backed by the
* specified multimap.
*
* <p>
* 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 <K, V> ListMultimap<K, V> synchronizedListMultimap(ListMultimap<K, V> 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}.
*
* <p>
* Note that the generated multimap's {@link Multimap#removeAll} and
* {@link Multimap#replaceValues} methods return collections that are
* modifiable.
*
* <p>
* The returned multimap will be serializable if the specified multimap is
* serializable.
*
* @param delegate the multimap for which an unmodifiable view is to be returned
* @return an unmodifiable view of the specified multimap
*/
public static <K, V> ListMultimap<K, V> unmodifiableListMultimap(ListMultimap<K, V> delegate) {
if (delegate instanceof UnmodifiableListMultimap || delegate instanceof ImmutableListMultimap) {
return delegate;
}
return new UnmodifiableListMultimap<K, V>(delegate);
}
/**
* Simply returns its argument.
*
* @deprecated no need to use this
* @since 10.0
*/
@Deprecated
public static <K, V> ListMultimap<K, V> unmodifiableListMultimap(ImmutableListMultimap<K, V> delegate) {
return checkNotNull(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 <V> Collection<V> unmodifiableValueCollection(Collection<V> collection) {
if (collection instanceof SortedSet) {
return Collections.unmodifiableSortedSet((SortedSet<V>) collection);
} else if (collection instanceof Set) {
return Collections.unmodifiableSet((Set<V>) collection);
} else if (collection instanceof List) {
return Collections.unmodifiableList((List<V>) collection);
}
return Collections.unmodifiableCollection(collection);
}
/**
* 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 <K, V> Collection<Entry<K, V>> unmodifiableEntries(Collection<Entry<K, V>> entries) {
if (entries instanceof Set) {
return Maps.unmodifiableEntrySet((Set<Entry<K, V>>) entries);
}
return new Maps.UnmodifiableEntries<K, V>(Collections.unmodifiableCollection(entries));
}
/**
* Returns {@link ListMultimap#asMap multimap.asMap()}, with its type corrected
* from {@code Map<K, Collection<V>>} to {@code Map<K, List<V>>}.
*
* @since 15.0
*/
@Beta
@SuppressWarnings("unchecked")
// safe by specification of ListMultimap.asMap()
public static <K, V> Map<K, List<V>> asMap(ListMultimap<K, V> multimap) {
return (Map<K, List<V>>) (Map<K, ?>) multimap.asMap();
}
/**
* Returns {@link SetMultimap#asMap multimap.asMap()}, with its type corrected
* from {@code Map<K, Collection<V>>} to {@code Map<K, Set<V>>}.
*
* @since 15.0
*/
@Beta
@SuppressWarnings("unchecked")
// safe by specification of SetMultimap.asMap()
public static <K, V> Map<K, Set<V>> asMap(SetMultimap<K, V> multimap) {
return (Map<K, Set<V>>) (Map<K, ?>) multimap.asMap();
}
/**
* Returns {@link SortedSetMultimap#asMap multimap.asMap()}, with its type
* corrected from {@code Map<K, Collection<V>>} to {@code Map<K, SortedSet<V>>}.
*
* @since 15.0
*/
@Beta
@SuppressWarnings("unchecked")
// safe by specification of SortedSetMultimap.asMap()
public static <K, V> Map<K, SortedSet<V>> asMap(SortedSetMultimap<K, V> multimap) {
return (Map<K, SortedSet<V>>) (Map<K, ?>) multimap.asMap();
}
/**
* Returns {@link Multimap#asMap multimap.asMap()}. This is provided for parity
* with the other more strongly-typed {@code asMap()} implementations.
*
* @since 15.0
*/
@Beta
public static <K, V> Map<K, Collection<V>> asMap(Multimap<K, V> multimap) {
return multimap.asMap();
}
/**
* 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.
*
* <p>
* 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}.
*
* <p>
* The returned multimap will be serializable if the specified map is
* serializable.
*
* @param map the backing map for the returned multimap view
*/
public static <K, V> SetMultimap<K, V> forMap(Map<K, V> map) {
return new MapMultimap<K, V>(map);
}
/** @see Multimaps#forMap */
private static class MapMultimap<K, V> extends AbstractMultimap<K, V> implements SetMultimap<K, V>, Serializable {
final Map<K, V> map;
MapMultimap(Map<K, V> map) {
this.map = checkNotNull(map);
}
@Override
public int size() {
return map.size();
}
@Override
public boolean containsKey(Object key) {
return map.containsKey(key);
}
@Override
public boolean containsValue(Object value) {
return map.containsValue(value);
}
@Override
public boolean containsEntry(Object key, Object value) {
return map.entrySet().contains(Maps.immutableEntry(key, value));
}
@Override
public Set<V> get(final K key) {
return new Sets.ImprovedAbstractSet<V>() {
@Override
public Iterator<V> iterator() {
return new Iterator<V>() {
int i;
@Override
public boolean hasNext() {
return (i == 0) && map.containsKey(key);
}
@Override
public V next() {
if (!hasNext()) {
throw new NoSuchElementException();
}
i++;
return map.get(key);
}
@Override
public void remove() {
checkRemove(i == 1);
i = -1;
map.remove(key);
}
};
}
@Override
public int size() {
return map.containsKey(key) ? 1 : 0;
}
};
}
@Override
public boolean put(K key, V value) {
throw new UnsupportedOperationException();
}
@Override
public boolean putAll(K key, Iterable<? extends V> values) {
throw new UnsupportedOperationException();
}
@Override
public boolean putAll(Multimap<? extends K, ? extends V> multimap) {
throw new UnsupportedOperationException();
}
@Override
public Set<V> replaceValues(K key, Iterable<? extends V> values) {
throw new UnsupportedOperationException();
}
@Override
public boolean remove(Object key, Object value) {
return map.entrySet().remove(Maps.immutableEntry(key, value));
}
@Override
public Set<V> removeAll(Object key) {
Set<V> values = new HashSet<V>(2);
if (!map.containsKey(key)) {
return values;
}
values.add(map.remove(key));
return values;
}
@Override
public void clear() {
map.clear();
}
@Override
public Set<K> keySet() {
return map.keySet();
}
@Override
public Collection<V> values() {
return map.values();
}
@Override
public Set<Entry<K, V>> entries() {
return map.entrySet();
}
@Override
Iterator<Entry<K, V>> entryIterator() {
return map.entrySet().iterator();
}
@Override
Map<K, Collection<V>> createAsMap() {
return new AsMap<K, V>(this);
}
@Override
public int hashCode() {
return map.hashCode();
}
private static final long serialVersionUID = 7845222491160860175L;
}
/**
* Returns a view of a multimap where each value is transformed by a function.
* All other properties of the multimap, such as iteration order, are left
* intact. For example, the code:
*
* <pre>
* {
* @code
*
* Multimap<String, Integer> multimap = ImmutableSetMultimap.of("a", 2, "b", -3, "b", -3, "a", 4, "c", 6);
* Function<Integer, String> square = new Function<Integer, String>() {
* public String apply(Integer in) {
* return Integer.toString(in * in);
* }
* };
* Multimap<String, String> transformed = Multimaps.transformValues(multimap, square);
* System.out.println(transformed);
* }
* </pre>
*
* ... prints {@code {a=[4, 16], b=[9, 9], c=[36]}}.
*
* <p>
* Changes in the underlying multimap are reflected in this view. Conversely,
* this view supports removal operations, and these are reflected in the
* underlying multimap.
*
* <p>
* It's acceptable for the underlying multimap to contain null keys, and even
* null values provided that the function is capable of accepting null input.
* The transformed multimap might contain null values, if the function sometimes
* gives a null result.
*
* <p>
* The returned multimap is not thread-safe or serializable, even if the
* underlying multimap is. The {@code equals} and {@code hashCode} methods of
* the returned multimap are meaningless, since there is not a definition of
* {@code equals} or {@code hashCode} for general collections, and {@code get()}
* will return a general {@code Collection} as opposed to a {@code List} or a
* {@code Set}.
*
* <p>
* The function is applied lazily, invoked when needed. This is necessary for
* the returned multimap to be a view, but it means that the function will be
* applied many times for bulk operations like {@link Multimap#containsValue}
* and {@code Multimap.toString()}. For this to perform well, {@code function}
* should be fast. To avoid lazy evaluation when the returned multimap doesn't
* need to be a view, copy the returned multimap into a new multimap of your
* choosing.
*
* @since 7.0
*/
public static <K, V1, V2> Multimap<K, V2> transformValues(Multimap<K, V1> fromMultimap,
final Function<? super V1, V2> function) {
checkNotNull(function);
EntryTransformer<K, V1, V2> transformer = Maps.asEntryTransformer(function);
return transformEntries(fromMultimap, transformer);
}
/**
* Returns a view of a multimap whose values are derived from the original
* multimap's entries. In contrast to {@link #transformValues}, this method's
* entry-transformation logic may depend on the key as well as the value.
*
* <p>
* All other properties of the transformed multimap, such as iteration order,
* are left intact. For example, the code:
*
* <pre>
* {
* @code
*
* SetMultimap<String, Integer> multimap = ImmutableSetMultimap.of("a", 1, "a", 4, "b", -6);
* EntryTransformer<String, Integer, String> transformer = new EntryTransformer<String, Integer, String>() {
* public String transformEntry(String key, Integer value) {
* return (value >= 0) ? key : "no" + key;
* }
* };
* Multimap<String, String> transformed = Multimaps.transformEntries(multimap, transformer);
* System.out.println(transformed);
* }
* </pre>
*
* ... prints {@code {a=[a, a], b=[nob]}}.
*
* <p>
* Changes in the underlying multimap are reflected in this view. Conversely,
* this view supports removal operations, and these are reflected in the
* underlying multimap.
*
* <p>
* It's acceptable for the underlying multimap to contain null keys and null
* values provided that the transformer is capable of accepting null inputs. The
* transformed multimap might contain null values if the transformer sometimes
* gives a null result.
*
* <p>
* The returned multimap is not thread-safe or serializable, even if the
* underlying multimap is. The {@code equals} and {@code hashCode} methods of
* the returned multimap are meaningless, since there is not a definition of
* {@code equals} or {@code hashCode} for general collections, and {@code get()}
* will return a general {@code Collection} as opposed to a {@code List} or a
* {@code Set}.
*
* <p>
* The transformer is applied lazily, invoked when needed. This is necessary for
* the returned multimap to be a view, but it means that the transformer will be
* applied many times for bulk operations like {@link Multimap#containsValue}
* and {@link Object#toString}. For this to perform well, {@code transformer}
* should be fast. To avoid lazy evaluation when the returned multimap doesn't
* need to be a view, copy the returned multimap into a new multimap of your
* choosing.
*
* <p>
* <b>Warning:</b> 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 multimap.
*
* @since 7.0
*/
public static <K, V1, V2> Multimap<K, V2> transformEntries(Multimap<K, V1> fromMap,
EntryTransformer<? super K, ? super V1, V2> transformer) {
return new TransformedEntriesMultimap<K, V1, V2>(fromMap, transformer);
}
private static class TransformedEntriesMultimap<K, V1, V2> extends AbstractMultimap<K, V2> {
final Multimap<K, V1> fromMultimap;
final EntryTransformer<? super K, ? super V1, V2> transformer;
TransformedEntriesMultimap(Multimap<K, V1> fromMultimap,
final EntryTransformer<? super K, ? super V1, V2> transformer) {
this.fromMultimap = checkNotNull(fromMultimap);
this.transformer = checkNotNull(transformer);
}
Collection<V2> transform(K key, Collection<V1> values) {
Function<? super V1, V2> function = Maps.asValueToValueFunction(transformer, key);
if (values instanceof List) {
return Lists.transform((List<V1>) values, function);
} else {
return Collections2.transform(values, function);
}
}
@Override
Map<K, Collection<V2>> createAsMap() {
return Maps.transformEntries(fromMultimap.asMap(),
new EntryTransformer<K, Collection<V1>, Collection<V2>>() {
@Override
public Collection<V2> transformEntry(K key, Collection<V1> value) {
return transform(key, value);
}
});
}
@Override
public void clear() {
fromMultimap.clear();
}
@Override
public boolean containsKey(Object key) {
return fromMultimap.containsKey(key);
}
@Override
Iterator<Entry<K, V2>> entryIterator() {
return Iterators.transform(fromMultimap.entries().iterator(),
Maps.<K, V1, V2>asEntryToEntryFunction(transformer));
}
@Override
public Collection<V2> get(final K key) {
return transform(key, fromMultimap.get(key));
}
@Override
public boolean isEmpty() {
return fromMultimap.isEmpty();
}
@Override
public Set<K> keySet() {
return fromMultimap.keySet();
}
@Override
public Multiset<K> keys() {
return fromMultimap.keys();
}
@Override
public boolean put(K key, V2 value) {
throw new UnsupportedOperationException();
}
@Override
public boolean putAll(K key, Iterable<? extends V2> values) {
throw new UnsupportedOperationException();
}
@Override
public boolean putAll(Multimap<? extends K, ? extends V2> multimap) {
throw new UnsupportedOperationException();
}
@SuppressWarnings("unchecked")
@Override
public boolean remove(Object key, Object value) {
return get((K) key).remove(value);
}
@SuppressWarnings("unchecked")
@Override
public Collection<V2> removeAll(Object key) {
return transform((K) key, fromMultimap.removeAll(key));
}
@Override
public Collection<V2> replaceValues(K key, Iterable<? extends V2> values) {
throw new UnsupportedOperationException();
}
@Override
public int size() {
return fromMultimap.size();
}
@Override
Collection<V2> createValues() {
return Collections2.transform(fromMultimap.entries(), Maps.<K, V1, V2>asEntryToValueFunction(transformer));
}
}
/**
* Returns a view of a {@code ListMultimap} where each value is transformed by a
* function. All other properties of the multimap, such as iteration order, are
* left intact. For example, the code:
*
* <pre>
* {
* @code
*
* ListMultimap<String, Integer> multimap = ImmutableListMultimap.of("a", 4, "a", 16, "b", 9);
* Function<Integer, Double> sqrt = new Function<Integer, Double>() {
* public Double apply(Integer in) {
* return Math.sqrt((int) in);
* }
* };
* ListMultimap<String, Double> transformed = Multimaps.transformValues(map, sqrt);
* System.out.println(transformed);
* }
* </pre>
*
* ... prints {@code {a=[2.0, 4.0], b=[3.0]}}.
*
* <p>
* Changes in the underlying multimap are reflected in this view. Conversely,
* this view supports removal operations, and these are reflected in the
* underlying multimap.
*
* <p>
* It's acceptable for the underlying multimap to contain null keys, and even
* null values provided that the function is capable of accepting null input.
* The transformed multimap might contain null values, if the function sometimes
* gives a null result.
*
* <p>
* The returned multimap is not thread-safe or serializable, even if the
* underlying multimap is.
*
* <p>
* The function is applied lazily, invoked when needed. This is necessary for
* the returned multimap to be a view, but it means that the function will be
* applied many times for bulk operations like {@link Multimap#containsValue}
* and {@code Multimap.toString()}. For this to perform well, {@code function}
* should be fast. To avoid lazy evaluation when the returned multimap doesn't
* need to be a view, copy the returned multimap into a new multimap of your
* choosing.
*
* @since 7.0
*/
public static <K, V1, V2> ListMultimap<K, V2> transformValues(ListMultimap<K, V1> fromMultimap,
final Function<? super V1, V2> function) {
checkNotNull(function);
EntryTransformer<K, V1, V2> transformer = Maps.asEntryTransformer(function);
return transformEntries(fromMultimap, transformer);
}
/**
* Returns a view of a {@code ListMultimap} whose values are derived from the
* original multimap's entries. In contrast to
* {@link #transformValues(ListMultimap, Function)}, this method's
* entry-transformation logic may depend on the key as well as the value.
*
* <p>
* All other properties of the transformed multimap, such as iteration order,
* are left intact. For example, the code:
*
* <pre>
* {
* @code
*
* Multimap<String, Integer> multimap = ImmutableMultimap.of("a", 1, "a", 4, "b", 6);
* EntryTransformer<String, Integer, String> transformer = new EntryTransformer<String, Integer, String>() {
* public String transformEntry(String key, Integer value) {
* return key + value;
* }
* };
* Multimap<String, String> transformed = Multimaps.transformEntries(multimap, transformer);
* System.out.println(transformed);
* }
* </pre>
*
* ... prints {@code {"a"=["a1", "a4"], "b"=["b6"]}}.
*
* <p>
* Changes in the underlying multimap are reflected in this view. Conversely,
* this view supports removal operations, and these are reflected in the
* underlying multimap.
*
* <p>
* It's acceptable for the underlying multimap to contain null keys and null
* values provided that the transformer is capable of accepting null inputs. The
* transformed multimap might contain null values if the transformer sometimes
* gives a null result.
*
* <p>
* The returned multimap is not thread-safe or serializable, even if the
* underlying multimap is.
*
* <p>
* The transformer is applied lazily, invoked when needed. This is necessary for
* the returned multimap to be a view, but it means that the transformer will be
* applied many times for bulk operations like {@link Multimap#containsValue}
* and {@link Object#toString}. For this to perform well, {@code transformer}
* should be fast. To avoid lazy evaluation when the returned multimap doesn't
* need to be a view, copy the returned multimap into a new multimap of your
* choosing.
*
* <p>
* <b>Warning:</b> 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 multimap.
*
* @since 7.0
*/
public static <K, V1, V2> ListMultimap<K, V2> transformEntries(ListMultimap<K, V1> fromMap,
EntryTransformer<? super K, ? super V1, V2> transformer) {
return new TransformedEntriesListMultimap<K, V1, V2>(fromMap, transformer);
}
private static final class TransformedEntriesListMultimap<K, V1, V2> extends TransformedEntriesMultimap<K, V1, V2>
implements ListMultimap<K, V2> {
TransformedEntriesListMultimap(ListMultimap<K, V1> fromMultimap,
EntryTransformer<? super K, ? super V1, V2> transformer) {
super(fromMultimap, transformer);
}
@Override
List<V2> transform(K key, Collection<V1> values) {
return Lists.transform((List<V1>) values, Maps.asValueToValueFunction(transformer, key));
}
@Override
public List<V2> get(K key) {
return transform(key, fromMultimap.get(key));
}
@SuppressWarnings("unchecked")
@Override
public List<V2> removeAll(Object key) {
return transform((K) key, fromMultimap.removeAll(key));
}
@Override
public List<V2> replaceValues(K key, Iterable<? extends V2> values) {
throw new UnsupportedOperationException();
}
}
/**
* Creates an index {@code ImmutableListMultimap} that contains the results of
* applying a specified function to each item in an {@code Iterable} of values.
* Each value will be stored as a value in the resulting multimap, yielding a
* multimap with the same size as the input iterable. The key used to store that
* value in the multimap will be the result of calling the function on that
* value. The resulting multimap is created as an immutable snapshot. In the
* returned multimap, keys appear in the order they are first encountered, and
* the values corresponding to each key appear in the same order as they are
* encountered.
*
* <p>
* For example,
*
* <pre>
* {@code
*
* List<String> badGuys =
* Arrays.asList("Inky", "Blinky", "Pinky", "Pinky", "Clyde");
* Function<String, Integer> stringLengthFunction = ...;
* Multimap<Integer, String> index =
* Multimaps.index(badGuys, stringLengthFunction);
* System.out.println(index);}
* </pre>
*
* <p>
* prints
*
* <pre>
* {@code
*
* {4=[Inky], 6=[Blinky], 5=[Pinky, Pinky, Clyde]}}
* </pre>
*
* <p>
* The returned multimap is serializable if its keys and values are all
* serializable.
*
* @param values the values to use when constructing the {@code
* ImmutableListMultimap}
* @param keyFunction the function used to produce the key for each value
* @return {@code ImmutableListMultimap} mapping the result of evaluating the
* function {@code keyFunction} on each value in the input collection to
* that value
* @throws NullPointerException if any of the following cases is true:
* <ul>
* <li>{@code values} is null
* <li>{@code keyFunction} is null
* <li>An element in {@code values} is null
* <li>{@code keyFunction} returns {@code null} for
* any element of {@code
* values}
* </ul>
*/
public static <K, V> ImmutableListMultimap<K, V> index(Iterable<V> values, Function<? super V, K> keyFunction) {
return index(values.iterator(), keyFunction);
}
/**
* Creates an index {@code ImmutableListMultimap} that contains the results of
* applying a specified function to each item in an {@code Iterator} of values.
* Each value will be stored as a value in the resulting multimap, yielding a
* multimap with the same size as the input iterator. The key used to store that
* value in the multimap will be the result of calling the function on that
* value. The resulting multimap is created as an immutable snapshot. In the
* returned multimap, keys appear in the order they are first encountered, and
* the values corresponding to each key appear in the same order as they are
* encountered.
*
* <p>
* For example,
*
* <pre>
* {@code
*
* List<String> badGuys =
* Arrays.asList("Inky", "Blinky", "Pinky", "Pinky", "Clyde");
* Function<String, Integer> stringLengthFunction = ...;
* Multimap<Integer, String> index =
* Multimaps.index(badGuys.iterator(), stringLengthFunction);
* System.out.println(index);}
* </pre>
*
* <p>
* prints
*
* <pre>
* {@code
*
* {4=[Inky], 6=[Blinky], 5=[Pinky, Pinky, Clyde]}}
* </pre>
*
* <p>
* The returned multimap is serializable if its keys and values are all
* serializable.
*
* @param values the values to use when constructing the {@code
* ImmutableListMultimap}
* @param keyFunction the function used to produce the key for each value
* @return {@code ImmutableListMultimap} mapping the result of evaluating the
* function {@code keyFunction} on each value in the input collection to
* that value
* @throws NullPointerException if any of the following cases is true:
* <ul>
* <li>{@code values} is null
* <li>{@code keyFunction} is null
* <li>An element in {@code values} is null
* <li>{@code keyFunction} returns {@code null} for
* any element of {@code
* values}
* </ul>
* @since 10.0
*/
public static <K, V> ImmutableListMultimap<K, V> index(Iterator<V> values, Function<? super V, K> keyFunction) {
checkNotNull(keyFunction);
ImmutableListMultimap.Builder<K, V> builder = ImmutableListMultimap.builder();
while (values.hasNext()) {
V value = values.next();
checkNotNull(value, values);
builder.put(keyFunction.apply(value), value);
}
return builder.build();
}
static class Keys<K, V> extends AbstractMultiset<K> {
final Multimap<K, V> multimap;
Keys(Multimap<K, V> multimap) {
this.multimap = multimap;
}
@Override
Iterator<Multiset.Entry<K>> entryIterator() {
return new TransformedIterator<Map.Entry<K, Collection<V>>, Multiset.Entry<K>>(
multimap.asMap().entrySet().iterator()) {
@Override
Multiset.Entry<K> transform(final Map.Entry<K, Collection<V>> backingEntry) {
return new Multisets.AbstractEntry<K>() {
@Override
public K getElement() {
return backingEntry.getKey();
}
@Override
public int getCount() {
return backingEntry.getValue().size();
}
};
}
};
}
@Override
int distinctElements() {
return multimap.asMap().size();
}
@Override
Set<Multiset.Entry<K>> createEntrySet() {
return new KeysEntrySet();
}
class KeysEntrySet extends Multisets.EntrySet<K> {
@Override
Multiset<K> multiset() {
return Keys.this;
}
@Override
public Iterator<Multiset.Entry<K>> iterator() {
return entryIterator();
}
@Override
public int size() {
return distinctElements();
}
@Override
public boolean isEmpty() {
return multimap.isEmpty();
}
@Override
public boolean contains(@Nullable Object o) {
if (o instanceof Multiset.Entry) {
Multiset.Entry<?> entry = (Multiset.Entry<?>) o;
Collection<V> collection = multimap.asMap().get(entry.getElement());
return collection != null && collection.size() == entry.getCount();
}
return false;
}
@Override
public boolean remove(@Nullable Object o) {
if (o instanceof Multiset.Entry) {
Multiset.Entry<?> entry = (Multiset.Entry<?>) o;
Collection<V> collection = multimap.asMap().get(entry.getElement());
if (collection != null && collection.size() == entry.getCount()) {
collection.clear();
return true;
}
}
return false;
}
}
@Override
public boolean contains(@Nullable Object element) {
return multimap.containsKey(element);
}
@Override
public Iterator<K> iterator() {
return Maps.keyIterator(multimap.entries().iterator());
}
@Override
public int count(@Nullable Object element) {
Collection<V> values = Maps.safeGet(multimap.asMap(), element);
return (values == null) ? 0 : values.size();
}
@Override
public int remove(@Nullable Object element, int occurrences) {
checkNonnegative(occurrences, "occurrences");
if (occurrences == 0) {
return count(element);
}
Collection<V> values = Maps.safeGet(multimap.asMap(), element);
if (values == null) {
return 0;
}
int oldCount = values.size();
if (occurrences >= oldCount) {
values.clear();
} else {
Iterator<V> iterator = values.iterator();
for (int i = 0; i < occurrences; i++) {
iterator.next();
iterator.remove();
}
}
return oldCount;
}
@Override
public void clear() {
multimap.clear();
}
@Override
public Set<K> elementSet() {
return multimap.keySet();
}
}
/**
* A skeleton implementation of {@link Multimap#entries()}.
*/
abstract static class Entries<K, V> extends AbstractCollection<Map.Entry<K, V>> {
abstract Multimap<K, V> multimap();
@Override
public int size() {
return multimap().size();
}
@Override
public boolean contains(@Nullable Object o) {
if (o instanceof Map.Entry) {
Map.Entry<?, ?> entry = (Map.Entry<?, ?>) o;
return multimap().containsEntry(entry.getKey(), entry.getValue());
}
return false;
}
@Override
public boolean remove(@Nullable Object o) {
if (o instanceof Map.Entry) {
Map.Entry<?, ?> entry = (Map.Entry<?, ?>) o;
return multimap().remove(entry.getKey(), entry.getValue());
}
return false;
}
@Override
public void clear() {
multimap().clear();
}
}
/**
* A skeleton implementation of {@link Multimap#asMap()}.
*/
static final class AsMap<K, V> extends Maps.ImprovedAbstractMap<K, Collection<V>> {
private final Multimap<K, V> multimap;
AsMap(Multimap<K, V> multimap) {
this.multimap = checkNotNull(multimap);
}
@Override
public int size() {
return multimap.keySet().size();
}
@Override
protected Set<Entry<K, Collection<V>>> createEntrySet() {
return new EntrySet();
}
void removeValuesForKey(Object key) {
multimap.keySet().remove(key);
}
class EntrySet extends Maps.EntrySet<K, Collection<V>> {
@Override
Map<K, Collection<V>> map() {
return AsMap.this;
}
@Override
public Iterator<Entry<K, Collection<V>>> iterator() {
return Maps.asMapEntryIterator(multimap.keySet(), new Function<K, Collection<V>>() {
@Override
public Collection<V> apply(K key) {
return multimap.get(key);
}
});
}
@Override
public boolean remove(Object o) {
if (!contains(o)) {
return false;
}
Map.Entry<?, ?> entry = (Map.Entry<?, ?>) o;
removeValuesForKey(entry.getKey());
return true;
}
}
@SuppressWarnings("unchecked")
@Override
public Collection<V> get(Object key) {
return containsKey(key) ? multimap.get((K) key) : null;
}
@Override
public Collection<V> remove(Object key) {
return containsKey(key) ? multimap.removeAll(key) : null;
}
@Override
public Set<K> keySet() {
return multimap.keySet();
}
@Override
public boolean isEmpty() {
return multimap.isEmpty();
}
@Override
public boolean containsKey(Object key) {
return multimap.containsKey(key);
}
@Override
public void clear() {
multimap.clear();
}
}
/**
* Returns a multimap containing the mappings in {@code unfiltered} whose keys
* satisfy a predicate. The returned multimap is a live view of
* {@code unfiltered}; changes to one affect the other.
*
* <p>
* The resulting multimap's views have iterators that don't support
* {@code remove()}, but all other methods are supported by the multimap and its
* views. When adding a key that doesn't satisfy the predicate, the multimap's
* {@code put()}, {@code putAll()}, and {@code replaceValues()} methods throw an
* {@link IllegalArgumentException}.
*
* <p>
* When methods such as {@code removeAll()} and {@code clear()} are called on
* the filtered multimap or its views, only mappings whose keys satisfy the
* filter will be removed from the underlying multimap.
*
* <p>
* The returned multimap isn't threadsafe or serializable, even if
* {@code unfiltered} is.
*
* <p>
* Many of the filtered multimap's methods, such as {@code size()}, iterate
* across every key/value mapping in the underlying multimap and determine which
* satisfy the filter. When a live view is <i>not</i> needed, it may be faster
* to copy the filtered multimap and use the copy.
*
* <p>
* <b>Warning:</b> {@code keyPredicate} must be <i>consistent with equals</i>,
* 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 <K, V> Multimap<K, V> filterKeys(Multimap<K, V> unfiltered, final Predicate<? super K> keyPredicate) {
if (unfiltered instanceof SetMultimap) {
return filterKeys((SetMultimap<K, V>) unfiltered, keyPredicate);
} else if (unfiltered instanceof ListMultimap) {
return filterKeys((ListMultimap<K, V>) unfiltered, keyPredicate);
} else if (unfiltered instanceof FilteredKeyMultimap) {
FilteredKeyMultimap<K, V> prev = (FilteredKeyMultimap<K, V>) unfiltered;
return new FilteredKeyMultimap<K, V>(prev.unfiltered, Predicates.and(prev.keyPredicate, keyPredicate));
} else if (unfiltered instanceof FilteredMultimap) {
FilteredMultimap<K, V> prev = (FilteredMultimap<K, V>) unfiltered;
return filterFiltered(prev, Maps.<K>keyPredicateOnEntries(keyPredicate));
} else {
return new FilteredKeyMultimap<K, V>(unfiltered, keyPredicate);
}
}
/**
* Returns a multimap containing the mappings in {@code unfiltered} whose keys
* satisfy a predicate. The returned multimap is a live view of
* {@code unfiltered}; changes to one affect the other.
*
* <p>
* The resulting multimap's views have iterators that don't support
* {@code remove()}, but all other methods are supported by the multimap and its
* views. When adding a key that doesn't satisfy the predicate, the multimap's
* {@code put()}, {@code putAll()}, and {@code replaceValues()} methods throw an
* {@link IllegalArgumentException}.
*
* <p>
* When methods such as {@code removeAll()} and {@code clear()} are called on
* the filtered multimap or its views, only mappings whose keys satisfy the
* filter will be removed from the underlying multimap.
*
* <p>
* The returned multimap isn't threadsafe or serializable, even if
* {@code unfiltered} is.
*
* <p>
* Many of the filtered multimap's methods, such as {@code size()}, iterate
* across every key/value mapping in the underlying multimap and determine which
* satisfy the filter. When a live view is <i>not</i> needed, it may be faster
* to copy the filtered multimap and use the copy.
*
* <p>
* <b>Warning:</b> {@code keyPredicate} must be <i>consistent with equals</i>,
* 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
*/
public static <K, V> SetMultimap<K, V> filterKeys(SetMultimap<K, V> unfiltered,
final Predicate<? super K> keyPredicate) {
if (unfiltered instanceof FilteredKeySetMultimap) {
FilteredKeySetMultimap<K, V> prev = (FilteredKeySetMultimap<K, V>) unfiltered;
return new FilteredKeySetMultimap<K, V>(prev.unfiltered(), Predicates.and(prev.keyPredicate, keyPredicate));
} else if (unfiltered instanceof FilteredSetMultimap) {
FilteredSetMultimap<K, V> prev = (FilteredSetMultimap<K, V>) unfiltered;
return filterFiltered(prev, Maps.<K>keyPredicateOnEntries(keyPredicate));
} else {
return new FilteredKeySetMultimap<K, V>(unfiltered, keyPredicate);
}
}
/**
* Returns a multimap containing the mappings in {@code unfiltered} whose keys
* satisfy a predicate. The returned multimap is a live view of
* {@code unfiltered}; changes to one affect the other.
*
* <p>
* The resulting multimap's views have iterators that don't support
* {@code remove()}, but all other methods are supported by the multimap and its
* views. When adding a key that doesn't satisfy the predicate, the multimap's
* {@code put()}, {@code putAll()}, and {@code replaceValues()} methods throw an
* {@link IllegalArgumentException}.
*
* <p>
* When methods such as {@code removeAll()} and {@code clear()} are called on
* the filtered multimap or its views, only mappings whose keys satisfy the
* filter will be removed from the underlying multimap.
*
* <p>
* The returned multimap isn't threadsafe or serializable, even if
* {@code unfiltered} is.
*
* <p>
* Many of the filtered multimap's methods, such as {@code size()}, iterate
* across every key/value mapping in the underlying multimap and determine which
* satisfy the filter. When a live view is <i>not</i> needed, it may be faster
* to copy the filtered multimap and use the copy.
*
* <p>
* <b>Warning:</b> {@code keyPredicate} must be <i>consistent with equals</i>,
* 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
*/
public static <K, V> ListMultimap<K, V> filterKeys(ListMultimap<K, V> unfiltered,
final Predicate<? super K> keyPredicate) {
if (unfiltered instanceof FilteredKeyListMultimap) {
FilteredKeyListMultimap<K, V> prev = (FilteredKeyListMultimap<K, V>) unfiltered;
return new FilteredKeyListMultimap<K, V>(prev.unfiltered(),
Predicates.and(prev.keyPredicate, keyPredicate));
} else {
return new FilteredKeyListMultimap<K, V>(unfiltered, keyPredicate);
}
}
/**
* Returns a multimap containing the mappings in {@code unfiltered} whose values
* satisfy a predicate. The returned multimap is a live view of
* {@code unfiltered}; changes to one affect the other.
*
* <p>
* The resulting multimap's views have iterators that don't support
* {@code remove()}, but all other methods are supported by the multimap and its
* views. When adding a value that doesn't satisfy the predicate, the multimap's
* {@code put()}, {@code putAll()}, and {@code replaceValues()} methods throw an
* {@link IllegalArgumentException}.
*
* <p>
* When methods such as {@code removeAll()} and {@code clear()} are called on
* the filtered multimap or its views, only mappings whose value satisfy the
* filter will be removed from the underlying multimap.
*
* <p>
* The returned multimap isn't threadsafe or serializable, even if
* {@code unfiltered} is.
*
* <p>
* Many of the filtered multimap's methods, such as {@code size()}, iterate
* across every key/value mapping in the underlying multimap and determine which
* satisfy the filter. When a live view is <i>not</i> needed, it may be faster
* to copy the filtered multimap and use the copy.
*
* <p>
* <b>Warning:</b> {@code valuePredicate} must be <i>consistent with equals</i>,
* 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 <K, V> Multimap<K, V> filterValues(Multimap<K, V> unfiltered,
final Predicate<? super V> valuePredicate) {
return filterEntries(unfiltered, Maps.<V>valuePredicateOnEntries(valuePredicate));
}
/**
* Returns a multimap containing the mappings in {@code unfiltered} whose values
* satisfy a predicate. The returned multimap is a live view of
* {@code unfiltered}; changes to one affect the other.
*
* <p>
* The resulting multimap's views have iterators that don't support
* {@code remove()}, but all other methods are supported by the multimap and its
* views. When adding a value that doesn't satisfy the predicate, the multimap's
* {@code put()}, {@code putAll()}, and {@code replaceValues()} methods throw an
* {@link IllegalArgumentException}.
*
* <p>
* When methods such as {@code removeAll()} and {@code clear()} are called on
* the filtered multimap or its views, only mappings whose value satisfy the
* filter will be removed from the underlying multimap.
*
* <p>
* The returned multimap isn't threadsafe or serializable, even if
* {@code unfiltered} is.
*
* <p>
* Many of the filtered multimap's methods, such as {@code size()}, iterate
* across every key/value mapping in the underlying multimap and determine which
* satisfy the filter. When a live view is <i>not</i> needed, it may be faster
* to copy the filtered multimap and use the copy.
*
* <p>
* <b>Warning:</b> {@code valuePredicate} must be <i>consistent with equals</i>,
* 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
*/
public static <K, V> SetMultimap<K, V> filterValues(SetMultimap<K, V> unfiltered,
final Predicate<? super V> valuePredicate) {
return filterEntries(unfiltered, Maps.<V>valuePredicateOnEntries(valuePredicate));
}
/**
* Returns a multimap containing the mappings in {@code unfiltered} that satisfy
* a predicate. The returned multimap is a live view of {@code unfiltered};
* changes to one affect the other.
*
* <p>
* The resulting multimap's views have iterators that don't support
* {@code remove()}, but all other methods are supported by the multimap and its
* views. When adding a key/value pair that doesn't satisfy the predicate,
* multimap's {@code put()}, {@code putAll()}, and {@code replaceValues()}
* methods throw an {@link IllegalArgumentException}.
*
* <p>
* When methods such as {@code removeAll()} and {@code clear()} are called on
* the filtered multimap or its views, only mappings whose keys satisfy the
* filter will be removed from the underlying multimap.
*
* <p>
* The returned multimap isn't threadsafe or serializable, even if
* {@code unfiltered} is.
*
* <p>
* Many of the filtered multimap's methods, such as {@code size()}, iterate
* across every key/value mapping in the underlying multimap and determine which
* satisfy the filter. When a live view is <i>not</i> needed, it may be faster
* to copy the filtered multimap and use the copy.
*
* <p>
* <b>Warning:</b> {@code entryPredicate} must be <i>consistent with equals</i>,
* as documented at {@link Predicate#apply}.
*
* @since 11.0
*/
public static <K, V> Multimap<K, V> filterEntries(Multimap<K, V> unfiltered,
Predicate<? super Entry<K, V>> entryPredicate) {
checkNotNull(entryPredicate);
if (unfiltered instanceof SetMultimap) {
return filterEntries((SetMultimap<K, V>) unfiltered, entryPredicate);
}
return (unfiltered instanceof FilteredMultimap)
? filterFiltered((FilteredMultimap<K, V>) unfiltered, entryPredicate)
: new FilteredEntryMultimap<K, V>(checkNotNull(unfiltered), entryPredicate);
}
/**
* Returns a multimap containing the mappings in {@code unfiltered} that satisfy
* a predicate. The returned multimap is a live view of {@code unfiltered};
* changes to one affect the other.
*
* <p>
* The resulting multimap's views have iterators that don't support
* {@code remove()}, but all other methods are supported by the multimap and its
* views. When adding a key/value pair that doesn't satisfy the predicate,
* multimap's {@code put()}, {@code putAll()}, and {@code replaceValues()}
* methods throw an {@link IllegalArgumentException}.
*
* <p>
* When methods such as {@code removeAll()} and {@code clear()} are called on
* the filtered multimap or its views, only mappings whose keys satisfy the
* filter will be removed from the underlying multimap.
*
* <p>
* The returned multimap isn't threadsafe or serializable, even if
* {@code unfiltered} is.
*
* <p>
* Many of the filtered multimap's methods, such as {@code size()}, iterate
* across every key/value mapping in the underlying multimap and determine which
* satisfy the filter. When a live view is <i>not</i> needed, it may be faster
* to copy the filtered multimap and use the copy.
*
* <p>
* <b>Warning:</b> {@code entryPredicate} must be <i>consistent with equals</i>,
* as documented at {@link Predicate#apply}.
*
* @since 14.0
*/
public static <K, V> SetMultimap<K, V> filterEntries(SetMultimap<K, V> unfiltered,
Predicate<? super Entry<K, V>> entryPredicate) {
checkNotNull(entryPredicate);
return (unfiltered instanceof FilteredSetMultimap)
? filterFiltered((FilteredSetMultimap<K, V>) unfiltered, entryPredicate)
: new FilteredEntrySetMultimap<K, V>(checkNotNull(unfiltered), entryPredicate);
}
/**
* Support removal operations when filtering a filtered multimap. Since a
* filtered multimap has iterators that don't support remove, passing one to the
* FilteredEntryMultimap constructor would lead to a multimap whose removal
* operations would fail. This method combines the predicates to avoid that
* problem.
*/
private static <K, V> Multimap<K, V> filterFiltered(FilteredMultimap<K, V> multimap,
Predicate<? super Entry<K, V>> entryPredicate) {
Predicate<Entry<K, V>> predicate = Predicates.and(multimap.entryPredicate(), entryPredicate);
return new FilteredEntryMultimap<K, V>(multimap.unfiltered(), predicate);
}
/**
* Support removal operations when filtering a filtered multimap. Since a
* filtered multimap has iterators that don't support remove, passing one to the
* FilteredEntryMultimap constructor would lead to a multimap whose removal
* operations would fail. This method combines the predicates to avoid that
* problem.
*/
private static <K, V> SetMultimap<K, V> filterFiltered(FilteredSetMultimap<K, V> multimap,
Predicate<? super Entry<K, V>> entryPredicate) {
Predicate<Entry<K, V>> predicate = Predicates.and(multimap.entryPredicate(), entryPredicate);
return new FilteredEntrySetMultimap<K, V>(multimap.unfiltered(), predicate);
}
static boolean equalsImpl(Multimap<?, ?> multimap, @Nullable Object object) {
if (object == multimap) {
return true;
}
if (object instanceof Multimap) {
Multimap<?, ?> that = (Multimap<?, ?>) object;
return multimap.asMap().equals(that.asMap());
}
return false;
}
// TODO(jlevy): Create methods that filter a SortedSetMultimap.
}