rice.p2p.util
Class SoftHashMap

java.lang.Object
  java.util.AbstractMap<K,V>
      java.util.HashMap
          rice.p2p.util.SoftHashMap

All Implemented Interfaces:

java.io.Serializable, java.lang.Cloneable, java.util.Map

public class SoftHashMap
extends java.util.HashMap

Class which implements a Soft-Reference based HashMap, allowing the garbage collector to collection stuff if memory pressure is tight. Should be transparent to applications, except that items may disappear.

Author:

Alan Mislove

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from class java.util.AbstractMap

java.util.AbstractMap.SimpleEntry<K,V>, java.util.AbstractMap.SimpleImmutableEntry<K,V>

Constructor Summary

SoftHashMap()

Method Summary

boolean	containsKey(java.lang.Object key) Returns whether or not the key is contained in this map.
boolean	containsValue(java.lang.Object value) Returns whether or not the value is contained in this map.
java.lang.Object	get(java.lang.Object key) Returns the object associated with the key.
java.lang.Object	put(java.lang.Object key, java.lang.Object value) Adds an entry to the soft hash map.

Methods inherited from class java.util.HashMap

clear, clone, entrySet, isEmpty, keySet, putAll, remove, size, values

Methods inherited from class java.util.AbstractMap

equals, hashCode, toString

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.util.Map

equals, hashCode

Constructor Detail

SoftHashMap

public SoftHashMap()

Method Detail

containsKey

public boolean containsKey(java.lang.Object key)

Returns whether or not the key is contained in this map. Only returns true if the softreference has not been GC'ed.

Specified by:

containsKey in interface java.util.Map

Overrides:

containsKey in class java.util.HashMap

Parameters:

key - The key to check for

Returns:

The result

containsValue

public boolean containsValue(java.lang.Object value)

Returns whether or not the value is contained in this map. Only returns true if the softreference has not been GC'ed.

Specified by:

containsValue in interface java.util.Map

Overrides:

containsValue in class java.util.HashMap

Parameters:

value - The value to check for

Returns:

The result

get

public java.lang.Object get(java.lang.Object key)

Returns the object associated with the key. May return null, if the soft reference has been GC'ed.

Specified by:

get in interface java.util.Map

Overrides:

get in class java.util.HashMap

Parameters:

key - The key

Returns:

The value

put

public java.lang.Object put(java.lang.Object key,
                            java.lang.Object value)

Adds an entry to the soft hash map. May not persist for very long, though.

Specified by:

put in interface java.util.Map

Overrides:

put in class java.util.HashMap

Parameters:

key - The key

value - The value

Returns:

The previous value of the key