Class Overview
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.
|
|
V
|
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.
|
|
V
|
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.
|
|
V
|
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.
|
|
[Expand]
Inherited Methods |
|---|
From class java.util.AbstractMap
|
void
|
clear()
Removes all elements from this Map, leaving it empty.
|
|
Object
|
clone()
Returns a new instance of the same class as the receiver, whose slots
have been filled in with the values in the slots of the receiver.
|
|
boolean
|
containsKey(Object key)
Searches this Map for the specified key.
|
|
boolean
|
containsValue(Object value)
Searches this Map for the specified value.
|
|
abstract
Set<Entry<K, V>>
|
entrySet()
Returns a set view of the mappings contained in this map.
|
|
boolean
|
equals(Object object)
Compares the specified object to this Map and answer if they are equal.
|
|
V
|
get(Object key)
Returns the value of the mapping with the specified key.
|
|
int
|
hashCode()
Returns an integer hash code for the receiver.
|
|
boolean
|
isEmpty()
Returns if this Map has no elements, a size of zero.
|
|
Set<K>
|
keySet()
Returns a Set of the keys contained in this Map.
|
|
V
|
put(K key, V value)
Maps the specified key to the specified value.
|
|
void
|
putAll(Map<? extends K, ? extends V> map)
Copies every mapping in the specified Map to this Map.
|
|
V
|
remove(Object key)
Removes a mapping with the specified key from this Map.
|
|
int
|
size()
Returns the number of elements in this Map.
|
|
String
|
toString()
Returns the string representation of this Map.
|
|
Collection<V>
|
values()
Returns a collection of the values contained in this map.
|
|
From class java.lang.Object
|
Object
|
clone()
Returns a new instance of the same class as the receiver, whose slots
have been filled in with the values in the slots of the receiver.
|
|
boolean
|
equals(Object o)
Compares the argument to the receiver, and returns true if they represent
the same object using a class specific comparison.
|
|
void
|
finalize()
Called by the virtual machine when there are no longer any (non-weak)
references to the receiver.
|
|
final
Class<? extends Object>
|
getClass()
Returns the unique instance of java.lang.Class which represents the class
of the receiver.
|
|
int
|
hashCode()
Returns an integer hash code for the receiver.
|
|
final
void
|
notify()
Causes one thread which is wait ing on the receiver to be
made ready to run.
|
|
final
void
|
notifyAll()
Causes all threads which are wait ing on the receiver to
be made ready to run.
|
|
String
|
toString()
Returns a string containing a concise, human-readable description of the
receiver.
|
|
final
void
|
wait(long time, int frac)
Causes the thread which sent this message to be made not ready to run
either pending some change in the receiver (as indicated by
notify or notifyAll) or the expiration of
the timeout.
|
|
final
void
|
wait(long time)
Causes the thread which sent this message to be made not ready to run
either pending some change in the receiver (as indicated by
notify or notifyAll) or the expiration of
the timeout.
|
|
final
void
|
wait()
Causes the thread which sent this message to be made not ready to run
pending some change in the receiver (as indicated by notify
or notifyAll).
|
|
From interface java.util.Map
|
abstract
void
|
clear()
Removes all elements from this Map, leaving it empty.
|
|
abstract
boolean
|
containsKey(Object key)
Searches this Map for the specified key.
|
|
abstract
boolean
|
containsValue(Object value)
Searches this Map for the specified value.
|
|
abstract
Set<Entry<K, V>>
|
entrySet()
Returns a Set whose elements comprise all of the mappings
that are to be found in this Map.
|
|
abstract
boolean
|
equals(Object object)
Compares the argument to the receiver, and returns true if they represent
the same object using a class specific comparison.
|
|
abstract
V
|
get(Object key)
Returns the value of the mapping with the specified key.
|
|
abstract
int
|
hashCode()
Returns an integer hash code for the receiver.
|
|
abstract
boolean
|
isEmpty()
Returns if this Map has no elements, a size of zero.
|
|
abstract
Set<K>
|
keySet()
Returns a Set of the keys contained in this Map.
|
|
abstract
V
|
put(K key, V value)
Maps the specified key to the specified value.
|
|
abstract
void
|
putAll(Map<? extends K, ? extends V> map)
Copies every mapping in the specified Map to this Map.
|
|
abstract
V
|
remove(Object key)
Removes a mapping with the specified key from this Map.
|
|
abstract
int
|
size()
Returns the number of elements in this Map.
|
|
abstract
Collection<V>
|
values()
Returns all of the current Map values in a
Collection.
|
|
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
