java.util.WeakHashMap<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
Public Methods
clear,
clone,
containsKey,
containsValue,
entrySet,
equals,
get,
hashCode,
isEmpty,
keySet,
put,
putAll,
remove,
size,
toString,
values
clone,
equals,
finalize,
getClass,
hashCode,
notify,
notifyAll,
toString,
wait,
wait,
wait
Methods inherited
from interface
java.util.Map
clear,
containsKey,
containsValue,
entrySet,
equals,
get,
hashCode,
isEmpty,
keySet,
put,
putAll,
remove,
size,
values
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 |
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 |
public
WeakHashMap(Map<? extends K, ? extends V> map)
Constructs a new instance of HashMap containing the mappings from the
specified Map.
Public Methods
public
void
clear()
Removes all mappings from this WeakHashMap, leaving it empty.
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.
public
V
get(Object key)
Returns the value of the mapping with the specified 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
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.
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 |
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
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