com.stoyanr.evictor.queue

Class NavigableMapEvictionQueue<K,V>

java.lang.Object

com.stoyanr.evictor.queue.NavigableMapEvictionQueue<K,V>

Type Parameters:

K - the type of keys maintained by this map

V - the type of mapped values

All Implemented Interfaces:

EvictionQueue<K,V>

public class NavigableMapEvictionQueue<K,V>
extends Object
implements EvictionQueue<K,V>

An EvictionQueue which uses a ConcurrentNavigableMap to store its entries. The key in the map is the eviction time of the entry, and the value is the entry itself.

Author:

Stoyan Rachev

Constructor Summary

Constructors

Constructor and Description
NavigableMapEvictionQueue() Creates a navigable map eviction queue with a ConcurrentSkipListMap.
NavigableMapEvictionQueue(ConcurrentNavigableMap<Long,EvictibleEntry<K,V>> map) Creates a navigable map eviction queue with the specified map.

Method Summary

Methods

Modifier and Type	Method and Description
boolean	evictEntries() Evicts all entries that have expired from their maps and removes them from the queue.
long	getNextEvictionTime() Returns the next eviction time of all entries contained in the queue, or 0 if the queue is empty.
boolean	hasEntries() Returns true if this queue contains any entries.
void	putEntry(EvictibleEntry<K,V> e) Puts the specified evictible entry into the queue.
void	removeEntry(EvictibleEntry<K,V> e) Removes the specified evictible entry from the queue.

Methods inherited from class java.lang.Object

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

Constructor Detail

NavigableMapEvictionQueue

public NavigableMapEvictionQueue()

Creates a navigable map eviction queue with a ConcurrentSkipListMap.

NavigableMapEvictionQueue

public NavigableMapEvictionQueue(ConcurrentNavigableMap<Long,EvictibleEntry<K,V>> map)

Creates a navigable map eviction queue with the specified map.

Parameters:

map - the map to be used

Throws:

NullPointerException - if the map is null

Method Detail

hasEntries

public boolean hasEntries()

Returns true if this queue contains any entries.

This implementation simply returns true if the map is non-empty and vice versa.

Specified by:

hasEntries in interface EvictionQueue<K,V>

Returns:

true if this queue contains any entries

getNextEvictionTime

public long getNextEvictionTime()

Returns the next eviction time of all entries contained in the queue, or 0 if the queue is empty. Since the queue is sorted by the entries eviction time, this is the eviction time of the first entry (head).

This implementation simply returns the first key in the map if it is non-empty, or 0 otherwise.

Specified by:

getNextEvictionTime in interface EvictionQueue<K,V>

Returns:

the next eviction time of all entries contained in the queue, or 0 if the queue is empty

putEntry

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

Puts the specified evictible entry into the queue.

This implementation simply invokes the put method on the map.

Specified by:

putEntry in interface EvictionQueue<K,V>

Parameters:

e - the entry to be put into the queue.

removeEntry

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

Removes the specified evictible entry from the queue.

This implementation simply invokes the remove method on the map.

Specified by:

removeEntry in interface EvictionQueue<K,V>

Parameters:

e - the entry to be removed from the queue.

evictEntries

public boolean evictEntries()

Evicts all entries that have expired from their maps and removes them from the queue.

This implementation uses the headMap method on the map to find all entries that should be evicted, and then calls the evict method on each one of them and removes them from the map.

Specified by:

evictEntries in interface EvictionQueue<K,V>

Returns:

true if any entries have been evicted