net.cscott.jutil
public class GenericMultiMap<K,V> extends AbstractMultiMap<K,V>
FSK: right now the implementation tries to preserve the property that if a key 'k' maps to an empty collection 'c' in some MultiMap 'mm', then users of 'mm' will not be able to see that 'k' is a member of the keySet for 'mm'. However, it does not preserve this property when mm.getValues(k) is used as a means to operate on the state of 'mm', and it is not clear to me whether one can even ensure that the property can be maintained if arbitrary operations on mm.getValues(k) are passed on to 'mm'.
Version: $Id: GenericMultiMap.java,v 1.6 2006-10-30 19:58:05 cananian Exp $
Constructor Summary | |
---|---|
GenericMultiMap() Creates a MultiMap using a HashMap for
the map and HashSets for the value collections.
| |
GenericMultiMap(CollectionFactory<V> cf) Creates a MultiMap using a HashMap for
the map and the specified CollectionFactory to
create the value collections. | |
GenericMultiMap(MapFactory<K,Collection<V>> mf, CollectionFactory<V> cf) Creates a MultiMap using the specified
MapFactory to create the map and the specified
CollectionFactory to create the value collections. |
Method Summary | |
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void | clear() |
boolean | contains(Object a, Object b) Returns true if a has a mapping to b
in this .
|
boolean | containsKey(Object key) |
boolean | containsValue(Object value) |
MultiMapSet<K,V> | entrySet() Returns a set view of the mappings contained in this map.
|
V | get(Object key) Returns some arbitrary value from the set of values to which
this map maps the specified key. |
Collection<V> | getValues(K key) Returns the collection of Values associated with
key . |
boolean | isEmpty() |
Set<K> | keySet() Returns a set view of the keys in this map. |
V | remove(Object key) Removes all mappings for this key from this map if present.
|
boolean | remove(Object key, Object value) Removes a mapping from key to value from this map if present.
|
int | size() |
Collection<V> | values() Returns a collection view of the values contained in this
map. |
this
, use the more
specific constructor
that takes CollectionFactorys.null
if
the map contains no mapping for the key; it's also possible
that the map explicitly maps the key to null
.
The containsKey
operation may be used to
distinquish these two cases.
Note that if only the put
method is used to
modify this
, then get
will operate
just as it would in any other Map.key
. Modifications to the returned
Collection affect this
as well. If
there are no Values currently associated with
key
, constructs a new, mutable, empty
Collection and returns it.
(MultiMap specific operation).null
if there was no mapping for key.this
was modified as a result of
this operation, else returns false.