@GwtCompatible public abstract class ForwardingMultimap<K,V> extends ForwardingObject implements Multimap<K,V>
default
method warning: This class does not forward calls to default
methods. Instead, it inherits their default implementations. When those implementations
invoke methods, they invoke methods on the ForwardingMultimap
.
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() ). |
toString
protected ForwardingMultimap()
protected abstract Multimap<K,V> delegate()
ForwardingObject
ForwardingSet.delegate()
. Concrete subclasses override this method to supply the
instance being decorated.delegate
in class ForwardingObject
public Map<K,Collection<V>> asMap()
Multimap
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()
Multimap
public boolean containsEntry(Object key, Object value)
Multimap
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(Object key)
Multimap
true
if this multimap contains at least one key-value pair with the key key
.containsKey
in interface Multimap<K,V>
public boolean containsValue(Object value)
Multimap
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()
Multimap
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(K key)
Multimap
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()
Multimap
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()
Multimap
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()
Multimap
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)
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)
Multimap
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)
Multimap
multimap
in this multimap, in the order returned by
multimap.entries()
.public boolean remove(Object key, Object value)
Multimap
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(Object key)
Multimap
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)
Multimap
If values
is empty, this is equivalent to removeAll(key)
.
replaceValues
in interface Multimap<K,V>
public int size()
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()
Multimap
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(Object object)
Multimap
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()
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.
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