@GwtCompatible public abstract class ForwardingMultimap<K,V> extends ForwardingObject implements Multimap<K,V>
A multimap which forwards all its method calls to another multimap. Subclasses should override one or more methods to modify the behavior of the backing multimap as desired per the decorator pattern.
| Modifier | Constructor and Description |
|---|---|
protected |
ForwardingMultimap()
Constructor for use by subclasses.
|
| Modifier and Type | Method and Description |
|---|---|
Map<K,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. |
void |
clear()
Removes all key-value pairs from the multimap, leaving it empty.
|
boolean |
containsEntry(Object key,
Object value)
Returns
true if this multimap contains at least one key-value pair with the key key and the value value. |
boolean |
containsKey(Object key)
Returns
true if this multimap contains at least one key-value pair with the key key. |
boolean |
containsValue(Object value)
Returns
true if this multimap contains at least one key-value pair with the value value. |
protected abstract Multimap<K,V> |
delegate()
Returns the backing delegate instance that methods are forwarded to.
|
Collection<Map.Entry<K,V>> |
entries()
Returns a view collection of all key-value pairs contained in this multimap, as
Map.Entry instances. |
boolean |
equals(Object object)
Compares the specified object with this multimap for equality.
|
Collection<V> |
get(K key)
Returns a view collection of the values associated with
key in this multimap, if any. |
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.
|
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,
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(Object key,
Object value)
Removes a single key-value pair with the key
key and the value value from this multimap, if such exists. |
Collection<V> |
removeAll(Object key)
Removes all values associated with the key
key. |
Collection<V> |
replaceValues(K key,
Iterable<? extends V> values)
Stores a collection of values with the same key, replacing any existing values for that key.
|
int |
size()
Returns the number of key-value pairs in this multimap.
|
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()). |
toStringprotected ForwardingMultimap()
Constructor for use by subclasses.
protected abstract Multimap<K,V> delegate()
ForwardingObjectReturns the backing delegate instance that methods are forwarded to. Abstract subclasses generally override this method with an abstract method that has a more specific return type, such as ForwardingSet.delegate(). Concrete subclasses override this method to supply the instance being decorated.
delegate in class ForwardingObjectpublic Map<K,Collection<V>> asMap()
MultimapReturns 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.
public void clear()
MultimapRemoves all key-value pairs from the multimap, leaving it empty.
public boolean containsEntry(@Nullable Object key, @Nullable Object value)
MultimapReturns true if this multimap contains at least one key-value pair with the key key and the value value.
containsEntry in interface Multimap<K,V>public boolean containsKey(@Nullable Object key)
MultimapReturns true if this multimap contains at least one key-value pair with the key key.
containsKey in interface Multimap<K,V>public boolean containsValue(@Nullable Object value)
MultimapReturns true if this multimap contains at least one key-value pair with the value value.
containsValue in interface Multimap<K,V>public Collection<Map.Entry<K,V>> entries()
MultimapReturns 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.
public Collection<V> get(@Nullable K key)
MultimapReturns a view collection of the values associated with key in this multimap, if any. Note that when containsKey(key) is false, this returns an empty collection, not null.
Changes to the returned collection will update the underlying multimap, and vice versa.
public boolean isEmpty()
MultimapReturns true if this multimap contains no key-value pairs. Equivalent to size() == 0, but can in some cases be more efficient.
public Multiset<K> keys()
MultimapReturns 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.
public Set<K> keySet()
MultimapReturns 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.
public boolean put(K key, V value)
MultimapStores 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.
public boolean putAll(K key, Iterable<? extends V> values)
MultimapStores 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.
public boolean putAll(Multimap<? extends K,? extends V> multimap)
MultimapStores all key-value pairs of multimap in this multimap, in the order returned by multimap.entries().
public boolean remove(@Nullable Object key, @Nullable Object value)
MultimapRemoves 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.
public Collection<V> removeAll(@Nullable Object key)
MultimapRemoves all values associated with the key key.
Once this method returns, key will not be mapped to any values, so it will not appear in Multimap.keySet(), Multimap.asMap(), or any other views.
public Collection<V> replaceValues(K key, Iterable<? extends V> values)
MultimapStores 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).
replaceValues in interface Multimap<K,V>public int size()
MultimapReturns the number of key-value pairs in this multimap.
Note: this method does not return the number of distinct keys in the multimap, which is given by keySet().size() or asMap().size(). See the opening section of the Multimap class documentation for clarification.
public Collection<V> values()
MultimapReturns 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.
public boolean equals(@Nullable Object object)
MultimapCompares 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.
public int hashCode()
MultimapReturns 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().
In general, two multimaps with identical key-value mappings may or may not have the same hash codes, depending on the implementation. For example, two SetMultimap instances with the same key-value mappings will have the same hashCode, but the hashCode of ListMultimap instances depends on the ordering of the values for each key.