Android
java.util
public class

java.util.WeakHashMap<K, V>

java.lang.Object
java.util.AbstractMap<K, V> Map<K, V>
java.util.WeakHashMap<K, V> Map<K, V>

WeakHashMap is an implementation of Map with keys which are WeakReferences. The key/value mapping is removed when the key is no longer referenced. All optional operations are supported, adding and removing. Keys and values can be any objects.

Summary

Public Constructors

            WeakHashMap()
Constructs a new empty instance of WeakHashMap.
            WeakHashMap(int capacity)
Constructs a new instance of WeakHashMap with the specified capacity.
            WeakHashMap(int capacity, float loadFactor)
Constructs a new instance of WeakHashMap with the specified capacity and load factor.
            WeakHashMap(Map<? extends K, ? extends V> map)
Constructs a new instance of HashMap containing the mappings from the specified Map.

Public Methods

          void  clear()
Removes all mappings from this WeakHashMap, leaving it empty.
          boolean  containsKey(Object key)
Searches this WeakHashMap for the specified key.
          boolean  containsValue(Object value)
Searches this WeakHashMap for the specified value, and returns true, if at least one entry has this object as its value.
          Set<Entry<K, V>>  entrySet()
Returns a Set of the mappings contained in this WeakHashMap.
          get(Object key)
Returns the value of the mapping with the specified key.
          boolean  isEmpty()
Returns if this WeakHashMap has no elements, a size of zero.
          Set<K>  keySet()
Returns a Set of the keys contained in this WeakHashMap.
          put(K key, V value)
Maps the specified key to the specified value.
          void  putAll(Map<? extends K, ? extends V> map)
Copies all the mappings in the given map to this map.
          remove(Object key)
Removes a mapping with the specified key from this WeakHashMap.
          int  size()
Returns the number of mappings in this WeakHashMap.
          Collection<V>  values()
Returns a Collection of the values contained in this WeakHashMap.
Methods inherited from class java.util.AbstractMap
Methods inherited from class java.lang.Object
Methods inherited from interface java.util.Map

Details

Public Constructors

public WeakHashMap()

Constructs a new empty instance of WeakHashMap.

public WeakHashMap(int capacity)

Constructs a new instance of WeakHashMap with the specified capacity.

Parameters

capacity the initial capacity of this WeakHashMap

Throws

IllegalArgumentException when the capacity is less than zero

public WeakHashMap(int capacity, float loadFactor)

Constructs a new instance of WeakHashMap with the specified capacity and load factor.

Parameters

capacity the initial capacity
loadFactor the initial load factor

Throws

IllegalArgumentException when the capacity is less than zero or the load factor is less or equal to zero

public WeakHashMap(Map<? extends K, ? extends V> map)

Constructs a new instance of HashMap containing the mappings from the specified Map.

Parameters

map the mappings to add

Public Methods

public void clear()

Removes all mappings from this WeakHashMap, leaving it empty.

See Also

public boolean containsKey(Object key)

Searches this WeakHashMap for the specified key.

Parameters

key the object to search for

Returns

  • true if key is a key of this WeakHashMap, false otherwise

public boolean containsValue(Object value)

Searches this WeakHashMap for the specified value, and returns true, if at least one entry has this object as its value.

Parameters

value the object to search for

Returns

  • true if value is a value in this WeakHashMap, false otherwise

public Set<Entry<K, V>> entrySet()

Returns a Set of the mappings contained in this WeakHashMap. Each element in the set is a Map.Entry. The set is backed by this WeakHashMap so changes to one are reflected by the other. The set does not support adding.

Returns

  • a Set of the mappings

public V get(Object key)

Returns the value of the mapping with the specified key.

Parameters

key the key

Returns

  • the value of the mapping with the specified key

public boolean isEmpty()

Returns if this WeakHashMap has no elements, a size of zero.

Returns

  • true if this HashMap has no elements, false otherwise

See Also

public Set<K> keySet()

Returns a Set of the keys contained in this WeakHashMap. The set is backed by this WeakHashMap so changes to one are reflected by the other. The set does not support adding.

Returns

  • a Set of the keys

public V put(K key, V value)

Maps the specified key to the specified value.

Parameters

key the key
value the value

Returns

  • the value of any previous mapping with the specified key or null if there was no mapping

public void putAll(Map<? extends K, ? extends V> map)

Copies all the mappings in the given map to this map. These mappings will replace all mappings that this map had for any of the keys currently in the given map.

Parameters

map the Map to copy mappings from

Throws

NullPointerException if the given map is null

public V remove(Object key)

Removes a mapping with the specified key from this WeakHashMap.

Parameters

key the key of the mapping to remove

Returns

  • the value of the removed mapping or null if key is not a key in this WeakHashMap

public int size()

Returns the number of mappings in this WeakHashMap.

Returns

  • the number of mappings in this WeakHashMap

public Collection<V> values()

Returns a Collection of the values contained in this WeakHashMap. The collection is backed by this WeakHashMap so changes to one are reflected by the other. The collection does not support adding.

Returns

  • a Collection of the values
Copyright 2007 Google Inc. Build 0.9_r1-98467 - 14 Aug 2008 18:48