net.sf.ehcache.store.cachingtier

Class CountBasedBackEnd<K,V>

java.lang.Object

net.sf.ehcache.util.concurrent.ConcurrentHashMap<K,V>

net.sf.ehcache.store.cachingtier.CountBasedBackEnd<K,V>

Type Parameters:

K - the key type

V - the value type

All Implemented Interfaces:

ConcurrentMap<K,V>, Map<K,V>, HeapCacheBackEnd<K,V>

public class CountBasedBackEnd<K,V>
extends ConcurrentHashMap<K,V>
implements HeapCacheBackEnd<K,V>

A backend to a OnHeapCachingTier that will be cap'ed based on the amount of entries

Author:

Alex Snaps

Nested Class Summary

Nested classes/interfaces inherited from class net.sf.ehcache.util.concurrent.ConcurrentHashMap

ConcurrentHashMap.EntrySetView<K,V>, ConcurrentHashMap.KeySetView<K,V>, ConcurrentHashMap.Node, ConcurrentHashMap.RemovalCallback, ConcurrentHashMap.Spliterator<T>, ConcurrentHashMap.TreeNode, ConcurrentHashMap.ValuesView<K,V>

Nested classes/interfaces inherited from interface net.sf.ehcache.store.cachingtier.HeapCacheBackEnd

HeapCacheBackEnd.EvictionCallback<K,V>

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

Map.Entry<K,V>

Field Summary

Fields inherited from class net.sf.ehcache.util.concurrent.ConcurrentHashMap

FAKE_NODE, FAKE_TREE_NODE

Constructor Summary

Constructors

Constructor and Description
CountBasedBackEnd(long maxEntriesLocalHeap) Constructs a cap'ed backend
CountBasedBackEnd(long maxEntriesLocalHeap, Policy policy) Constructs a cap'ed backend

Method Summary

Modifier and Type	Method and Description
void	clear(boolean notify) Basically CHM.clear()
long	getMaxEntriesLocalHeap() Reads the current capacity limit
Policy	getPolicy() queries the potential eviction policy for the heap caching tier
boolean	hasSpace() Return true if this tier has enough space for more entries.
V	putIfAbsent(K key, V value)
void	recalculateSize(K key) This is evil! Don't call this!
void	registerEvictionCallback(HeapCacheBackEnd.EvictionCallback<K,V> evictionCallback) Let's you register a single callback for evictions
V	remove(Object key) Removes the key (and its corresponding value) from this map.
void	setMaxEntriesLocalHeap(long maxEntriesLocalHeap) Sets the capacity limit
void	setPolicy(Policy policy) Dynamic property to switch the policy out

Methods inherited from class net.sf.ehcache.util.concurrent.ConcurrentHashMap

clear, contains, containsKey, containsValue, elements, entrySet, entrySpliterator, equals, get, getRandomValues, getValueOrDefault, hashCode, internalPutIfAbsent, isEmpty, keys, keySet, keySet, keySpliterator, mappingCount, newKeySet, newKeySet, put, putAll, remove, remove, removeAndNotify, removeAndNotify, replace, replace, setPoolAccessor, size, toString, values, valueSpliterator

Methods inherited from class java.lang.Object

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

Methods inherited from interface net.sf.ehcache.store.cachingtier.HeapCacheBackEnd

entrySet, get, remove, replace, size

Methods inherited from interface java.util.concurrent.ConcurrentMap

compute, computeIfAbsent, computeIfPresent, forEach, getOrDefault, merge, replaceAll

Constructor Detail

CountBasedBackEnd

public CountBasedBackEnd(long maxEntriesLocalHeap)

Constructs a cap'ed backend

Parameters:

maxEntriesLocalHeap - amount of mappings this should hold before it starts evicting

CountBasedBackEnd

public CountBasedBackEnd(long maxEntriesLocalHeap,
                         Policy policy)

Constructs a cap'ed backend

Parameters:

maxEntriesLocalHeap - amount of mappings this should hold before it starts evicting

policy - the policy it'll use to decide what to evict

Method Detail

setPolicy

public void setPolicy(Policy policy)

Dynamic property to switch the policy out

Specified by:

setPolicy in interface HeapCacheBackEnd<K,V>

Parameters:

policy - the new eviction Policy to use

putIfAbsent

public V putIfAbsent(K key,
                     V value)

Specified by:

putIfAbsent in interface ConcurrentMap<K,V>

Specified by:

putIfAbsent in interface Map<K,V>

Specified by:

putIfAbsent in interface HeapCacheBackEnd<K,V>

Overrides:

putIfAbsent in class ConcurrentHashMap<K,V>

Parameters:

key - key with which the specified value is to be associated

value - value to be associated with the specified key

Returns:

the previous value associated with the specified key, or null if there was no mapping for the key

registerEvictionCallback

public void registerEvictionCallback(HeapCacheBackEnd.EvictionCallback<K,V> evictionCallback)

Let's you register a single callback for evictions

Specified by:

registerEvictionCallback in interface HeapCacheBackEnd<K,V>

Parameters:

evictionCallback - the thing to call back on

recalculateSize

public void recalculateSize(K key)

Description copied from interface: HeapCacheBackEnd

This is evil! Don't call this!

Specified by:

recalculateSize in interface HeapCacheBackEnd<K,V>

Overrides:

recalculateSize in class ConcurrentHashMap<K,V>

remove

public V remove(Object key)

Description copied from class: ConcurrentHashMap

Removes the key (and its corresponding value) from this map. This method does nothing if the key is not in the map.

Specified by:

remove in interface Map<K,V>

Specified by:

remove in interface HeapCacheBackEnd<K,V>

Overrides:

remove in class ConcurrentHashMap<K,V>

Parameters:

key - the key that needs to be removed

Returns:

the previous value associated with key, or null if there was no mapping for key

getPolicy

public Policy getPolicy()

Description copied from interface: HeapCacheBackEnd

queries the potential eviction policy for the heap caching tier

Specified by:

getPolicy in interface HeapCacheBackEnd<K,V>

Returns:

the policy

clear

public void clear(boolean notify)

Description copied from interface: HeapCacheBackEnd

Basically CHM.clear()

Specified by:

clear in interface HeapCacheBackEnd<K,V>

Parameters:

notify - whether to notify listeners or not

hasSpace

public boolean hasSpace()

Description copied from interface: HeapCacheBackEnd

Return true if this tier has enough space for more entries.

Specified by:

hasSpace in interface HeapCacheBackEnd<K,V>

Returns:

true if there is space for more entries.

setMaxEntriesLocalHeap

public void setMaxEntriesLocalHeap(long maxEntriesLocalHeap)

Sets the capacity limit

Parameters:

maxEntriesLocalHeap - the new limit

getMaxEntriesLocalHeap

public long getMaxEntriesLocalHeap()

Reads the current capacity limit

Returns:

the capacity limit