com.beasys.commerce.util
Class SoftHashMap

java.lang.Object
  java.util.AbstractMap
      com.beasys.commerce.util.SoftHashMap

All Implemented Interfaces:

Cloneable, Map, Serializable

public class SoftHashMap

extends AbstractMap

implements Map, Cloneable, Serializable

A map implemented using SoftReferences to store the values.

Unlike the java.util.WeakHashMap implementation, this does not utilize a ReferenceQueue, therefore, the References are cleared immediately, rather than only after a modification to the Map. Additionally, since this uses SoftReferences by default, the Map shouldn't be immediately cleared. Finally, this is also cloneable and serializable.

Since:

2.0.1-sp1

See Also:

Serialized Form

Constructor Summary

SoftHashMap()
Constructs a new, empty SoftHashMap with the default capacity and the default load factor, which is 0.75.

SoftHashMap(int initialCapacity)
Constructs a new, empty SoftHashMap with the given initial capacity and the default load factor, which is 0.75.

SoftHashMap(int initialCapacity, float loadFactor)
Constructs a new, empty SoftHashMap with the given initial capacity and the given load factor.

SoftHashMap(Map map)
Constructs a new SoftHashMap from the specified Map.

Method Summary

void	clear() Removes all mappings from this map.
Object	clone() Return a shallow clone of this map.
boolean	containsKey(Object key) Returns true if this map contains a mapping for the specified key.
boolean	containsValue(Object value) Returns true if this map contains the specified value.
protected Reference	createReference(Object data) Create a Reference object containing the specified object.
Set	entrySet() Returns a Set view of the mappings in this map.
Object	get(Object key) Returns the value to which this map maps the specified key.
boolean	isEmpty() Returns true if this map contains no key-value mappings.
Object	put(Object key, Object value) Updates this map so that the given key maps to the given value.
Object	remove(Object key) Removes the mapping for the given key from this map, if present.
int	size() Returns the number of key-value mappings in this map.

Methods inherited from class java.util.AbstractMap

equals, hashCode, keySet, putAll, toString, values

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.Map

equals, hashCode, keySet, putAll, values

Constructor Detail

SoftHashMap

public SoftHashMap()

Constructs a new, empty SoftHashMap with the default capacity and the default load factor, which is 0.75.

SoftHashMap

public SoftHashMap(int initialCapacity)

Constructs a new, empty SoftHashMap with the given initial capacity and the default load factor, which is 0.75.

Throws:

IllegalArgumentException - If the initial capacity is less than zero

SoftHashMap

public SoftHashMap(int initialCapacity,
                   float loadFactor)

Constructs a new, empty SoftHashMap with the given initial capacity and the given load factor.

Throws:

IllegalArgumentException - If the initial capacity is less than zero, or if the load factor is nonpositive

SoftHashMap

public SoftHashMap(Map map)

Constructs a new SoftHashMap from the specified Map.

Method Detail

clear

public void clear()

Removes all mappings from this map.

Specified by:

clear in interface Map

clone

public Object clone()

Return a shallow clone of this map.

containsKey

public boolean containsKey(Object key)

Returns true if this map contains a mapping for the specified key.

Specified by:

containsKey in interface Map

Parameters:

key - The key whose presence in this map is to be tested

containsValue

public boolean containsValue(Object value)

Returns true if this map contains the specified value.

Specified by:

containsValue in interface Map

createReference

protected Reference createReference(Object data)

Create a Reference object containing the specified object.

This implementation returns SoftReferences. Subclasses can override to return other Reference types.

Parameters:

data - the object (can be null).

Returns:

a Reference (can be null if data is null).

entrySet

public Set entrySet()

Returns a Set view of the mappings in this map.

Specified by:

entrySet in interface Map

get

public Object get(Object key)

Returns the value to which this map maps the specified key. If this map does not contain a value for this key, then return null.

Specified by:

get in interface Map

Parameters:

key - The key whose associated value, if any, is to be returned

isEmpty

public boolean isEmpty()

Returns true if this map contains no key-value mappings.

Specified by:

isEmpty in interface Map

put

public Object put(Object key,
                  Object value)

Updates this map so that the given key maps to the given value. If the map previously contained a mapping for key then that mapping is replaced and the previous value is returned.

Specified by:

put in interface Map

Parameters:

key - The key that is to be mapped to the given value

value - The value to which the given key is to be mapped

Returns:

The previous value to which this key was mapped, or null if if there was no mapping for the key

remove

public Object remove(Object key)

Removes the mapping for the given key from this map, if present.

Specified by:

remove in interface Map

Parameters:

key - The key whose mapping is to be removed

Returns:

The value to which this key was mapped, or null if there was no mapping for the key

size

public int size()

Returns the number of key-value mappings in this map. Note: In contrast with most implementations of the Map interface, the time required by this operation is linear in the size of the map.

Specified by:

size in interface Map