org.jboss.cache.eviction
Class LFUQueue

java.lang.Object
  org.jboss.cache.eviction.LFUQueue

All Implemented Interfaces:

EvictionQueue, SortedEvictionQueue

public class LFUQueue
extends java.lang.Object
implements SortedEvictionQueue

LFUQueue EvictionQueue implementation for LFU Policy.

The queue is sorted in least frequently used order.

Version:

$Revision: 1.5 $

Author:

Daniel Huang (dhuang@jboss.org)

Method Summary

void	addNodeEntry(NodeEntry entry) Add a NodeEntry to the queue.
void	clear() Clear the queue.
boolean	containsNodeEntry(NodeEntry entry) Check if queue contains the given NodeEntry.
NodeEntry	getFirstNodeEntry() Return the first node to evict.
NodeEntry	getNodeEntry(Fqn fqn) Retrieve a node entry by Fqn.
NodeEntry	getNodeEntry(java.lang.String fqn)
int	getNumberOfElements() Get the number of elements in the queue.
int	getNumberOfNodes() Get the number of nodes in the queue.
java.util.Iterator	iterate()
void	modifyElementCount(int difference)
void	removeNodeEntry(NodeEntry entry) Remove a NodeEntry from queue.
void	resortEvictionQueue() Provide contract to resort a sorted queue.

Methods inherited from class java.lang.Object

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

Method Detail

getFirstNodeEntry

public NodeEntry getFirstNodeEntry()

Return the first node to evict.

This method will return the least frequently used entry in the queue.

Specified by:

getFirstNodeEntry in interface EvictionQueue

Returns:

first NodeEntry in queue.

getNodeEntry

public NodeEntry getNodeEntry(Fqn fqn)

Description copied from interface: EvictionQueue

Retrieve a node entry by Fqn.

This will return null if the entry is not found.

Specified by:

getNodeEntry in interface EvictionQueue

Parameters:

fqn - Fqn of the node entry to retrieve.

Returns:

Node Entry object associated with given Fqn param.

getNodeEntry

public NodeEntry getNodeEntry(java.lang.String fqn)

Specified by:

getNodeEntry in interface EvictionQueue

containsNodeEntry

public boolean containsNodeEntry(NodeEntry entry)

Description copied from interface: EvictionQueue

Check if queue contains the given NodeEntry.

Specified by:

containsNodeEntry in interface EvictionQueue

Parameters:

entry - NodeEntry to check for existence in queue.

Returns:

true/false if NodeEntry exists in queue.

removeNodeEntry

public void removeNodeEntry(NodeEntry entry)

Description copied from interface: EvictionQueue

Remove a NodeEntry from queue.

If the NodeEntry does not exist in the queue, this method will return normally.

Specified by:

removeNodeEntry in interface EvictionQueue

Parameters:

entry - The NodeEntry to remove from queue.

addNodeEntry

public void addNodeEntry(NodeEntry entry)

Description copied from interface: EvictionQueue

Add a NodeEntry to the queue.

Specified by:

addNodeEntry in interface EvictionQueue

Parameters:

entry - The NodeEntry to add to queue.

getNumberOfNodes

public int getNumberOfNodes()

Description copied from interface: EvictionQueue

Get the number of nodes in the queue.

Specified by:

getNumberOfNodes in interface EvictionQueue

Returns:

The number of nodes in the queue.

getNumberOfElements

public int getNumberOfElements()

Description copied from interface: EvictionQueue

Get the number of elements in the queue.

Specified by:

getNumberOfElements in interface EvictionQueue

Returns:

The number of elements in the queue.

clear

public void clear()

Description copied from interface: EvictionQueue

Clear the queue.

Specified by:

clear in interface EvictionQueue

resortEvictionQueue

public void resortEvictionQueue()

Description copied from interface: SortedEvictionQueue

Provide contract to resort a sorted queue.

Specified by:

resortEvictionQueue in interface SortedEvictionQueue

modifyElementCount

public void modifyElementCount(int difference)

Specified by:

modifyElementCount in interface EvictionQueue

iterate

public java.util.Iterator iterate()

Specified by:

iterate in interface EvictionQueue