com.google.common.collect

Class AbstractMultimap<K,V>

java.lang.Object

com.google.common.collect.AbstractMultimap<K,V>

All Implemented Interfaces:

Multimap<K,V>

Direct Known Subclasses:

AbstractMapBasedMultimap, FilteredEntryMultimap, FilteredKeyMultimap, ImmutableMultimap, LinkedListMultimap, Multimaps.MapMultimap, Multimaps.TransformedEntriesMultimap

@GwtCompatible
abstract class AbstractMultimap<K,V>
extends java.lang.Object
implements Multimap<K,V>

A skeleton Multimap implementation, not necessarily in terms of a Map.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
private class	AbstractMultimap.Entries
private class	AbstractMultimap.EntrySet
(package private) class	AbstractMultimap.Values

Field Summary

Fields

Modifier and Type	Field and Description
private java.util.Map<K,java.util.Collection<V>>	asMap
private java.util.Collection<java.util.Map.Entry<K,V>>	entries
private Multiset<K>	keys
private java.util.Set<K>	keySet
private java.util.Collection<V>	values

Constructor Summary

Constructors

Constructor and Description
AbstractMultimap()

Method Summary

Modifier and Type	Method and Description
java.util.Map<K,java.util.Collection<V>>	asMap() Returns a view of this multimap as a Map from each distinct key to the nonempty collection of that key's associated values.
boolean	containsEntry(java.lang.Object key, java.lang.Object value) Returns true if this multimap contains at least one key-value pair with the key key and the value value.
boolean	containsValue(java.lang.Object value) Returns true if this multimap contains at least one key-value pair with the value value.
(package private) abstract java.util.Map<K,java.util.Collection<V>>	createAsMap()
(package private) java.util.Collection<java.util.Map.Entry<K,V>>	createEntries()
(package private) Multiset<K>	createKeys()
(package private) java.util.Set<K>	createKeySet()
(package private) java.util.Collection<V>	createValues()
java.util.Collection<java.util.Map.Entry<K,V>>	entries() Returns a view collection of all key-value pairs contained in this multimap, as Map.Entry instances.
(package private) abstract java.util.Iterator<java.util.Map.Entry<K,V>>	entryIterator()
boolean	equals(java.lang.Object object) Compares the specified object with this multimap for equality.
int	hashCode() Returns the hash code for this multimap.
boolean	isEmpty() Returns true if this multimap contains no key-value pairs.
Multiset<K>	keys() Returns a view collection containing the key from each key-value pair in this multimap, without collapsing duplicates.
java.util.Set<K>	keySet() Returns a view collection of all distinct keys contained in this multimap.
boolean	put(K key, V value) Stores a key-value pair in this multimap.
boolean	putAll(K key, java.lang.Iterable<? extends V> values) Stores a key-value pair in this multimap for each of values, all using the same key, key.
boolean	putAll(Multimap<? extends K,? extends V> multimap) Stores all key-value pairs of multimap in this multimap, in the order returned by multimap.entries().
boolean	remove(java.lang.Object key, java.lang.Object value) Removes a single key-value pair with the key key and the value value from this multimap, if such exists.
java.util.Collection<V>	replaceValues(K key, java.lang.Iterable<? extends V> values) Stores a collection of values with the same key, replacing any existing values for that key.
java.lang.String	toString() Returns a string representation of the multimap, generated by calling toString on the map returned by Multimap.asMap().
(package private) java.util.Iterator<V>	valueIterator()
java.util.Collection<V>	values() Returns a view collection containing the value from each key-value pair contained in this multimap, without collapsing duplicates (so values().size() == size()).

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface com.google.common.collect.Multimap

clear, containsKey, get, removeAll, size

Field Detail

entries

private transient java.util.Collection<java.util.Map.Entry<K,V>> entries

keySet

private transient java.util.Set<K> keySet

keys

private transient Multiset<K> keys

values

private transient java.util.Collection<V> values

asMap

private transient java.util.Map<K,java.util.Collection<V>> asMap

Constructor Detail

AbstractMultimap

AbstractMultimap()

Method Detail

isEmpty

public boolean isEmpty()

Description copied from interface: Multimap

Returns true if this multimap contains no key-value pairs. Equivalent to size() == 0, but can in some cases be more efficient.

Specified by:

isEmpty in interface Multimap<K,V>

containsValue

public boolean containsValue(@Nullable
                             java.lang.Object value)

Description copied from interface: Multimap

Returns true if this multimap contains at least one key-value pair with the value value.

Specified by:

containsValue in interface Multimap<K,V>

containsEntry

public boolean containsEntry(@Nullable
                             java.lang.Object key,
                             @Nullable
                             java.lang.Object value)

Description copied from interface: Multimap

Returns true if this multimap contains at least one key-value pair with the key key and the value value.

Specified by:

containsEntry in interface Multimap<K,V>

remove

public boolean remove(@Nullable
                      java.lang.Object key,
                      @Nullable
                      java.lang.Object value)

Description copied from interface: Multimap

Removes a single key-value pair with the key key and the value value from this multimap, if such exists. If multiple key-value pairs in the multimap fit this description, which one is removed is unspecified.

Specified by:

remove in interface Multimap<K,V>

Returns:

true if the multimap changed

put

public boolean put(@Nullable
                   K key,
                   @Nullable
                   V value)

Description copied from interface: Multimap

Stores a key-value pair in this multimap.

Some multimap implementations allow duplicate key-value pairs, in which case put always adds a new key-value pair and increases the multimap size by 1. Other implementations prohibit duplicates, and storing a key-value pair that's already in the multimap has no effect.

Specified by:

put in interface Multimap<K,V>

Returns:

true if the method increased the size of the multimap, or false if the multimap already contained the key-value pair and doesn't allow duplicates

putAll

public boolean putAll(@Nullable
                      K key,
                      java.lang.Iterable<? extends V> values)

Description copied from interface: Multimap

Stores a key-value pair in this multimap for each of values, all using the same key, key. Equivalent to (but expected to be more efficient than):

   

   for (V value : values) {
     put(key, value);
   }

In particular, this is a no-op if values is empty.

Specified by:

putAll in interface Multimap<K,V>

Returns:

true if the multimap changed

putAll

public boolean putAll(Multimap<? extends K,? extends V> multimap)

Description copied from interface: Multimap

Stores all key-value pairs of multimap in this multimap, in the order returned by multimap.entries().

Specified by:

putAll in interface Multimap<K,V>

Returns:

true if the multimap changed

replaceValues

public java.util.Collection<V> replaceValues(@Nullable
                                             K key,
                                             java.lang.Iterable<? extends V> values)

Description copied from interface: Multimap

Stores a collection of values with the same key, replacing any existing values for that key.

If values is empty, this is equivalent to removeAll(key).

Specified by:

replaceValues in interface Multimap<K,V>

Returns:

the collection of replaced values, or an empty collection if no values were previously associated with the key. The collection may be modifiable, but updating it will have no effect on the multimap.

entries

public java.util.Collection<java.util.Map.Entry<K,V>> entries()

Description copied from interface: Multimap

Returns a view collection of all key-value pairs contained in this multimap, as Map.Entry instances.

Changes to the returned collection or the entries it contains will update the underlying multimap, and vice versa. However, adding to the returned collection is not possible.

Specified by:

entries in interface Multimap<K,V>

createEntries

java.util.Collection<java.util.Map.Entry<K,V>> createEntries()

entryIterator

abstract java.util.Iterator<java.util.Map.Entry<K,V>> entryIterator()

keySet

public java.util.Set<K> keySet()

Description copied from interface: Multimap

Returns a view collection of all distinct keys contained in this multimap. Note that the key set contains a key if and only if this multimap maps that key to at least one value.

Changes to the returned set will update the underlying multimap, and vice versa. However, adding to the returned set is not possible.

Specified by:

keySet in interface Multimap<K,V>

createKeySet

java.util.Set<K> createKeySet()

keys

public Multiset<K> keys()

Description copied from interface: Multimap

Returns a view collection containing the key from each key-value pair in this multimap, without collapsing duplicates. This collection has the same size as this multimap, and keys().count(k) == get(k).size() for all k.

Changes to the returned multiset will update the underlying multimap, and vice versa. However, adding to the returned collection is not possible.

Specified by:

keys in interface Multimap<K,V>

createKeys

Multiset<K> createKeys()

values

public java.util.Collection<V> values()

Description copied from interface: Multimap

Returns a view collection containing the value from each key-value pair contained in this multimap, without collapsing duplicates (so values().size() == size()).

Changes to the returned collection will update the underlying multimap, and vice versa. However, adding to the returned collection is not possible.

Specified by:

values in interface Multimap<K,V>

createValues

java.util.Collection<V> createValues()

valueIterator

java.util.Iterator<V> valueIterator()

asMap

public java.util.Map<K,java.util.Collection<V>> asMap()

Description copied from interface: Multimap

Returns a view of this multimap as a Map from each distinct key to the nonempty collection of that key's associated values. Note that this.asMap().get(k) is equivalent to this.get(k) only when k is a key contained in the multimap; otherwise it returns null as opposed to an empty collection.

Changes to the returned map or the collections that serve as its values will update the underlying multimap, and vice versa. The map does not support put or putAll, nor do its entries support setValue.

Specified by:

asMap in interface Multimap<K,V>

createAsMap

abstract java.util.Map<K,java.util.Collection<V>> createAsMap()

equals

public boolean equals(@Nullable
                      java.lang.Object object)

Description copied from interface: Multimap

Compares the specified object with this multimap for equality. Two multimaps are equal when their map views, as returned by Multimap.asMap(), are also equal.

In general, two multimaps with identical key-value mappings may or may not be equal, depending on the implementation. For example, two SetMultimap instances with the same key-value mappings are equal, but equality of two ListMultimap instances depends on the ordering of the values for each key.

A non-empty SetMultimap cannot be equal to a non-empty ListMultimap, since their Multimap.asMap() views contain unequal collections as values. However, any two empty multimaps are equal, because they both have empty Multimap.asMap() views.

Specified by:

equals in interface Multimap<K,V>

Overrides:

equals in class java.lang.Object

hashCode

public int hashCode()

Returns the hash code for this multimap.

The hash code of a multimap is defined as the hash code of the map view, as returned by Multimap.asMap().

Specified by:

hashCode in interface Multimap<K,V>

Overrides:

hashCode in class java.lang.Object

See Also:

Map.hashCode()

toString

public java.lang.String toString()

Returns a string representation of the multimap, generated by calling toString on the map returned by Multimap.asMap().

Overrides:

toString in class java.lang.Object

Returns:

a string representation of the multimap