ptolemy.util

Class MultiHashMap<K,V>

java.lang.Object

ptolemy.util.MultiHashMap<K,V>

Type Parameters:

K - The type of the keys of the multimap.

V - The type of the values of the multimap.

public class MultiHashMap<K,V>
extends java.lang.Object

MultiHashMap is an implementation of the MultiMap interface. It associates a collection of objects to each key. Putting a new object under a key adds to the associated collection. Likewise, removing a object removes from the collection. It is possible that the given object to remove is not contained by the collection. In which case, no changes is made and null is returned. The items in each collection are ordered by insertion, and duplicates are stored in the collections. For example, given a key K and object O1, and O2: MultiHashMap map = new MultiHashMap(); map.put(K, O1); map.put(K, O1); map.put(K, O2); then, map.size(K) would return 3. Iterating through the map returns O1, O1, and O2 in order.

Since:

Ptolemy II 8.0

Version:

$Id$

Author:

Man-Kit Leung, Ben Lickly

Pt.AcceptedRating:

Red (mankit)

Pt.ProposedRating:

Red (mankit)

Constructor Summary

Constructors

Constructor and Description
MultiHashMap()

Method Summary

Modifier and Type	Method and Description
java.util.Collection<V>	get(K key) Get the collection of values mapped to by a given key.
boolean	isEmpty() Return whether or not this multimap is empty.
java.util.Set<K>	keySet() Return a set of all key values represented by this multimap.
void	put(K key, V value) Add the value to the collection associated with the specified key.
boolean	remove(K key, V value) Remove a specified value from the map.
int	size(java.lang.Object key) Return the size of the collection mapped to the specified key.
java.util.Collection<V>	values() Return a view of the collection containing all values in the map.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

MultiHashMap

public MultiHashMap()

Method Detail

get

public java.util.Collection<V> get(K key)

Get the collection of values mapped to by a given key.

Parameters:

key - The index into the multimap.

Returns:

The collection of values at that index.

keySet

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

Return a set of all key values represented by this multimap.

Returns:

A set of values that are keys of this multimap.

isEmpty

public boolean isEmpty()

Return whether or not this multimap is empty.

Returns:

True, if the map is empty. False, otherwise.

put

public void put(K key,
                V value)

Add the value to the collection associated with the specified key.

Parameters:

key - The specified key.

value - The specified value to add to the collection.

remove

public boolean remove(K key,
                      V value)

Remove a specified value from the map. The value is removed from the collection mapped to the specified key. If this is the last value removed from the given key, the specified key is also removed from the map. Subsequent call to get(key) will return false.

Parameters:

key - The specified key to remove the value from.

value - The specified value to remove.

Returns:

True, if the value was removed. False, otherwise.

size

public int size(java.lang.Object key)

Return the size of the collection mapped to the specified key.

Parameters:

key - The specified key.

Returns:

The size of the collection, or zero if key is not in the map.

values

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

Return a view of the collection containing all values in the map. This is a collection containing the union of each collection mapped to the keys.

Returns:

A view of all values contained in this map.