net.sf.ehcache.pool.impl
Class AbstractBalancedAccessEvictor<T>

java.lang.Object
  net.sf.ehcache.pool.impl.AbstractBalancedAccessEvictor<T>

Type Parameters:

T - type of store handled by this evictor

All Implemented Interfaces:

PoolEvictor<T>

Direct Known Subclasses:

BalancedAccessOnDiskPoolEvictor, BalancedAccessOnHeapPoolEvictor

public abstract class AbstractBalancedAccessEvictor<T>
extends Object
implements PoolEvictor<T>

Abstract implementation of a global 'cache value' maximizing pool eviction algorithm.

Author:

Chris Dennis

Constructor Summary

AbstractBalancedAccessEvictor()

Method Summary

protected abstract long	byteSize(T store) Return the size in bytes of the supplied store.
protected abstract long	countSize(T store) Return the number of mappings in the supplied store.
protected abstract boolean	evict(T store, int count, long bytes) Evict the specified number of bytes or the hinted number of elements from the specified store
boolean	freeSpace(Collection<T> from, long bytes) Free at least N bytes from a collection of resources
protected abstract float	hitRate(T store) Return the hit rate for the supplied store.
protected abstract float	missRate(T store) Return the miss rate for the supplied store.

Methods inherited from class java.lang.Object

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

Constructor Detail

AbstractBalancedAccessEvictor

public AbstractBalancedAccessEvictor()

Method Detail

evict

protected abstract boolean evict(T store,
                                 int count,
                                 long bytes)

Evict the specified number of bytes or the hinted number of elements from the specified store

Parameters:

store - store to evict from

count - number of elements to evict

bytes - number of bytes to evict

Returns:

true if the eviction succeeded

hitRate

protected abstract float hitRate(T store)

Return the hit rate for the supplied store.

Parameters:

store - store to query

Returns:

hit rate

missRate

protected abstract float missRate(T store)

Return the miss rate for the supplied store.

Parameters:

store - store to query

Returns:

miss rate

countSize

protected abstract long countSize(T store)

Return the number of mappings in the supplied store.

Parameters:

store - store to size

Returns:

mapping count

byteSize

protected abstract long byteSize(T store)

Return the size in bytes of the supplied store.

Parameters:

store - store to size

Returns:

size in bytes

freeSpace

public boolean freeSpace(Collection<T> from,
                         long bytes)

Free at least N bytes from a collection of resources

Specified by:

freeSpace in interface PoolEvictor<T>

Parameters:

from - a collection of resources to free from

bytes - the number of bytes to free up

Returns:

true if at least N bytes could be freed