com.stoyanr.evictor.scheduler

Class AbstractQueueEvictionScheduler<K,V>

java.lang.Object

com.stoyanr.evictor.scheduler.AbstractQueueEvictionScheduler<K,V>

Type Parameters:

K - the type of keys maintained by this map

V - the type of mapped values

All Implemented Interfaces:

EvictionScheduler<K,V>

Direct Known Subclasses:

DelayedTaskEvictionScheduler, RegularTaskEvictionScheduler, SingleThreadEvictionScheduler

public abstract class AbstractQueueEvictionScheduler<K,V>
extends Object
implements EvictionScheduler<K,V>

An abstract EvictionScheduler which uses an EvictionQueue to store EvictibleEntry instances in the order they should be evicted. This class does not implement the actual eviction functionality, it should be implemented by its subclasses.

Author:

Stoyan Rachev

Constructor Summary

Constructors

Constructor and Description
AbstractQueueEvictionScheduler() Creates an eviction scheduler with a NavigableMapEvictionQueue.
AbstractQueueEvictionScheduler(EvictionQueue<K,V> queue) Creates an eviction scheduler with the specified queue.

Method Summary

Methods

Modifier and Type	Method and Description
void	cancelEviction(EvictibleEntry<K,V> e) Cancels the eviction of the specified entry from its map.
protected void	evictEntries() Evicts all entries by calling the evictEntries method on the queue.
protected long	getNextEvictionTime() Gets the time of the next scheduled eviction, in nanoseconds.
protected boolean	hasScheduledEvictions() Returns true if there are any evictions scheduled.
protected abstract void	onCancelEviction(EvictibleEntry<K,V> e) Actually cancels the eviction of the specified entry.
protected abstract void	onEvictEntries() Performs additional activities upon automated eviction of entries, if needed.
protected abstract void	onScheduleEviction(EvictibleEntry<K,V> e) Actually schedules the eviction of the specified entry.
void	scheduleEviction(EvictibleEntry<K,V> e) Schedules the eviction of the specified entry from its map.

Methods inherited from class java.lang.Object

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

Methods inherited from interface com.stoyanr.evictor.EvictionScheduler

shutdown

Constructor Detail

AbstractQueueEvictionScheduler

public AbstractQueueEvictionScheduler()

Creates an eviction scheduler with a NavigableMapEvictionQueue.

AbstractQueueEvictionScheduler

public AbstractQueueEvictionScheduler(EvictionQueue<K,V> queue)

Creates an eviction scheduler with the specified queue.

Parameters:

queue - the queue to be used

Throws:

NullPointerExceptin - if the queue is null

Method Detail

scheduleEviction

public void scheduleEviction(EvictibleEntry<K,V> e)

Schedules the eviction of the specified entry from its map. This method is called by the associated instances of ConcurrentMapWithTimedEvictionDecorator just after a new entry has been added. The entry is not guaranteed to be evictible, it may also be a permanent entry. Therefore, the implementation should check if this entry is evictible before doing any scheduling.

Specified by:

scheduleEviction in interface EvictionScheduler<K,V>

Parameters:

e - the entry for which the eviction should be scheduled, if evictible; it must have been already added to its map

cancelEviction

public void cancelEviction(EvictibleEntry<K,V> e)

Cancels the eviction of the specified entry from its map. This method is called by the associated instances of ConcurrentMapWithTimedEvictionDecorator just after an entry has been removed. The entry is not guaranteed to be evictible, it may also be a permanent entry. Therefore, the implementation should check if this entry is evictible before doing any cancellation.

Specified by:

cancelEviction in interface EvictionScheduler<K,V>

Parameters:

e - the entry for which the eviction should be cancelled, if evictible; it must have been already removed from its map

evictEntries

protected void evictEntries()

Evicts all entries by calling the evictEntries method on the queue. This method should be called by tasks running in dedicated eviction threads that manage the automated eviction.

hasScheduledEvictions

protected boolean hasScheduledEvictions()

Returns true if there are any evictions scheduled. This simply calls the hasEntries method on the queue.

getNextEvictionTime

protected long getNextEvictionTime()

Gets the time of the next scheduled eviction, in nanoseconds. This simply calls the getNextEvictionTime method on the queue.

onScheduleEviction

protected abstract void onScheduleEviction(EvictibleEntry<K,V> e)

Actually schedules the eviction of the specified entry. It is guaranteed that this entry is evictible. Subclasses should override this method to provide the actual scheduling functionality.

Parameters:

e - the entry for which the eviction should be scheduled

onCancelEviction

protected abstract void onCancelEviction(EvictibleEntry<K,V> e)

Actually cancels the eviction of the specified entry. It is guaranteed that this entry is evictible. Subclasses should override this method to provide the actual cancellation functionality.

Parameters:

e - the entry for which the eviction should be cancelled

onEvictEntries

protected abstract void onEvictEntries()

Performs additional activities upon automated eviction of entries, if needed. Subclasses should override this method if they need to perform such activities.

Parameters:

e - the entry for which the eviction should be scheduled