kodo.util
Class CacheMap

java.lang.Object
  |
  +--kodo.util.CacheMap

All Implemented Interfaces:

Map

public class CacheMap

extends Object

implements Map

A map that keeps hard references to a fixed number of elements and moves expired references to a soft reference map. Additionally, objects that are pinned are not counted towards the max size of the map. This implementation is thread-safe.

Inner classes inherited from class java.util.Map

Map.Entry

Field Summary

protected com.solarmetric.util.MutableMaxSizeLRUMap	_lruMap The map for non-expired and pinned references.
protected HashMap	_pinnedMap The set of objects pinned into the cache.
protected serp.util.ReferenceMap	_softMap The map for expired references.

Constructor Summary

CacheMap()
Create a new CacheMap with an initial maximum unpinned object size of 1000.

CacheMap(int size)
Create a new CacheMap with an initial maximum unpinned object size of size.

CacheMap(int size, float load)
Create a new CacheMap with an initial maximum unpinned object size of size and a load factor of load.

CacheMap(int size, float load, int max)
Create a new CacheMap with an initial size of size, load factor of load, and maximum unpinned object size of max.

Method Summary

void	clear() Removes pinned objects as well as unpinned ones.
boolean	containsKey(Object key)
boolean	containsValue(Object val)
Set	entrySet()
Object	get(Object key)
int	getCacheSize() Returns the maximum number of unpinned objects to keep hard references to.
Set	getPinnedKeys() Returns the keys to the objects currently pinned into memory.
int	getSoftReferenceSize() Returns the maximum number of unpinned objects to keep soft references to.
Collection	getStatistics()
boolean	isEmpty()
protected void	keyRemoved(Object key, boolean expired) Invoked when a key-value pair is evicted from this data structure.
Set	keySet()
boolean	pin(Object key) Locks the key-value pair identified by key into the map.
Object	put(Object key, Object value)
void	putAll(Map map)
Object	remove(Object key) If key is pinned into the cache, the pin is cleared and the object is removed.
void	setCacheSize(int size) Sets the maximum number of unpinned objects to keep hard references to.
void	setSoftReferenceSize(int size) Sets the maximum number of unpinned objects to keep soft references to.
int	size()
boolean	unpin(Object key) Removes the key-value pair identified by key from the set of pinned objects.
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

equals, hashCode

Field Detail

_softMap

protected final serp.util.ReferenceMap _softMap

The map for expired references.

_lruMap

protected final com.solarmetric.util.MutableMaxSizeLRUMap _lruMap

The map for non-expired and pinned references.

_pinnedMap

protected HashMap _pinnedMap

The set of objects pinned into the cache.

Constructor Detail

CacheMap

public CacheMap()

Create a new CacheMap with an initial maximum unpinned object size of 1000.

CacheMap

public CacheMap(int size)

Create a new CacheMap with an initial maximum unpinned object size of size.

CacheMap

public CacheMap(int size,
                float load)

Create a new CacheMap with an initial maximum unpinned object size of size and a load factor of load.

CacheMap

public CacheMap(int size,
                float load,
                int max)

Create a new CacheMap with an initial size of size, load factor of load, and maximum unpinned object size of max.

Method Detail

setCacheSize

public void setCacheSize(int size)

Sets the maximum number of unpinned objects to keep hard references to. If the map contains more unpinned objects than size, then this method will result in the cache flushing old values. If this is -1, the cache will never be flushed.

getCacheSize

public int getCacheSize()

Returns the maximum number of unpinned objects to keep hard references to.

setSoftReferenceSize

public void setSoftReferenceSize(int size)

Sets the maximum number of unpinned objects to keep soft references to. If the map contains more soft references than size, then this method will result in the cache flushing some of the soft references. If this is -1, the cache will store a limitless number of soft references. Defaults to -1.

getSoftReferenceSize

public int getSoftReferenceSize()

Returns the maximum number of unpinned objects to keep soft references to.

getPinnedKeys

public Set getPinnedKeys()

Returns the keys to the objects currently pinned into memory.

pin

public boolean pin(Object key)

Locks the key-value pair identified by key into the map. Objects pinned into the map are not counted towards the maximum size of the map, and are never removed except by explicit calls to remove(java.lang.Object) or clear().

If a key that is not currently in the cache is pinned, it will not be considered pinned once that key is used in the cache.

Returns:

true if key's value was pinned into the cache; false if the key is not in the cache.

unpin

public boolean unpin(Object key)

Removes the key-value pair identified by key from the set of pinned objects. This key becomes a candidate for removal from the LRU map if the map exceeds the maximum size.

Returns:

true if key's value was unpinned from the cache; false if the key is not in the cache.

keyRemoved

protected void keyRemoved(Object key,
                          boolean expired)

Invoked when a key-value pair is evicted from this data structure. This is invoked with expired set to true when an object is dropped because of space requirements or through garbage collection of soft references. It is invoked with expired set to false when an object is explicitly removed via the remove(java.lang.Object) or clear() methods.

This may be invoked more than once for a given key.

Since:

2.5.0

get

public Object get(Object key)

Specified by:

get in interface Map

put

public Object put(Object key,
                  Object value)

Specified by:

put in interface Map

putAll

public void putAll(Map map)

Specified by:

putAll in interface Map

remove

public Object remove(Object key)

If key is pinned into the cache, the pin is cleared and the object is removed.

Specified by:

remove in interface Map

clear

public void clear()

Removes pinned objects as well as unpinned ones.

Specified by:

clear in interface Map

size

public int size()

Specified by:

size in interface Map

isEmpty

public boolean isEmpty()

Specified by:

isEmpty in interface Map

containsKey

public boolean containsKey(Object key)

Specified by:

containsKey in interface Map

containsValue

public boolean containsValue(Object val)

Specified by:

containsValue in interface Map

keySet

public Set keySet()

Specified by:

keySet in interface Map

values

public Collection values()

Specified by:

values in interface Map

entrySet

public Set entrySet()

Specified by:

entrySet in interface Map

getStatistics

public Collection getStatistics()