org.datanucleus.cache

Class SoftRefCache

java.lang.Object

org.datanucleus.cache.SoftRefCache

All Implemented Interfaces:

Map<Object,ObjectProvider>, Level1Cache

public class SoftRefCache
extends Object
implements Level1Cache

Level 1 Cache using Soft referenced objects in a Map.

If map entry value object is not actively being used, i.e. no other object has a strong reference to it, it may become garbage collected at the discretion of the garbage collector (typically if the VM is low on memory). If this happens, the entry in the SoftValueMap corresponding to the value object will also be removed.

See Also:

SoftReference

Nested Class Summary

Nested classes/interfaces inherited from interface java.util.Map

Map.Entry<K,V>

Constructor Summary

Constructors

Constructor and Description
SoftRefCache()

Method Summary

Modifier and Type	Method and Description
void	clear()
boolean	containsKey(Object id)
boolean	containsValue(Object value)
Set	entrySet()
ObjectProvider	get(Object id)
ObjectProvider	getUnique(CacheUniqueKey key) Method to retrieve the ObjectProvider for the specified unique key.
boolean	isEmpty()
Set	keySet()
ObjectProvider	put(Object id, ObjectProvider op)
void	putAll(Map t)
Object	putUnique(CacheUniqueKey key, ObjectProvider op) Method to store an ObjectProvider for this unique key.
ObjectProvider	remove(Object id)
int	size()
Collection	values()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface java.util.Map

compute, computeIfAbsent, computeIfPresent, equals, forEach, getOrDefault, hashCode, merge, putIfAbsent, remove, replace, replace, replaceAll

Constructor Detail

SoftRefCache

public SoftRefCache()

Method Detail

put

public ObjectProvider put(Object id,
                          ObjectProvider op)

Specified by:

put in interface Map<Object,ObjectProvider>

get

public ObjectProvider get(Object id)

Specified by:

get in interface Map<Object,ObjectProvider>

containsKey

public boolean containsKey(Object id)

Specified by:

containsKey in interface Map<Object,ObjectProvider>

remove

public ObjectProvider remove(Object id)

Specified by:

remove in interface Map<Object,ObjectProvider>

clear

public void clear()

Specified by:

clear in interface Map<Object,ObjectProvider>

containsValue

public boolean containsValue(Object value)

Specified by:

containsValue in interface Map<Object,ObjectProvider>

entrySet

public Set entrySet()

Specified by:

entrySet in interface Map<Object,ObjectProvider>

isEmpty

public boolean isEmpty()

Specified by:

isEmpty in interface Map<Object,ObjectProvider>

keySet

public Set keySet()

Specified by:

keySet in interface Map<Object,ObjectProvider>

putAll

public void putAll(Map t)

Specified by:

putAll in interface Map<Object,ObjectProvider>

size

public int size()

Specified by:

size in interface Map<Object,ObjectProvider>

values

public Collection values()

Specified by:

values in interface Map<Object,ObjectProvider>

getUnique

public ObjectProvider getUnique(CacheUniqueKey key)

Description copied from interface: Level1Cache

Method to retrieve the ObjectProvider for the specified unique key.

Specified by:

getUnique in interface Level1Cache

Parameters:

key - Unique key

Returns:

The ObjectProvider if one is cached for this unique key

putUnique

public Object putUnique(CacheUniqueKey key,
                        ObjectProvider op)

Description copied from interface: Level1Cache

Method to store an ObjectProvider for this unique key.

Specified by:

putUnique in interface Level1Cache

Parameters:

key - The unique key

op - The ObjectProvider

Returns:

The previous ObjectProvider for this unique key if one was present, otherwise null