net.sf.ehcache.store.chm
Class SelectableConcurrentHashMap

java.lang.Object
  net.sf.ehcache.store.chm.SelectableConcurrentHashMap

public class SelectableConcurrentHashMap
extends Object

SelectableConcurrentHashMap subclasses a repackaged version of ConcurrentHashMap ito allow efficient random sampling of the map values.

The random sampling technique involves randomly selecting a map Segment, and then selecting a number of random entry chains from that segment.

Author:

Chris Dennis

Nested Class Summary

static class	SelectableConcurrentHashMap.HashEntry
class	SelectableConcurrentHashMap.Segment

Constructor Summary

SelectableConcurrentHashMap(PoolAccessor poolAccessor, int initialCapacity, float loadFactor, int concurrency, long maximumSize, RegisteredEventListeners cacheEventNotificationService)

SelectableConcurrentHashMap(PoolAccessor poolAccessor, int concurrency, long maximumSize, RegisteredEventListeners cacheEventNotificationService)

Method Summary

void	clear()
boolean	containsKey(Object key)
boolean	containsValue(Object value)
protected SelectableConcurrentHashMap.Segment	createSegment(int initialCapacity, float lf)
Set<Map.Entry<Object,Element>>	entrySet()
boolean	evict()
Element	get(Object key)
Element[]	getRandomValues(int size, Object keyHint)
protected static int	hash(int h)
boolean	isEmpty()
Set<Object>	keySet()
ReentrantReadWriteLock	lockFor(Object key)
ReentrantReadWriteLock[]	locks()
Element	put(Object key, Element element, long sizeOf)
Element	putIfAbsent(Object key, Element element, long sizeOf)
int	quickSize() Returns the number of key-value mappings in this map without locking anything.
void	recalculateSize(Object key)
Element	remove(Object key)
boolean	remove(Object key, Object value)
protected SelectableConcurrentHashMap.Segment	segmentFor(int hash) Returns the segment that should be used for key with given hash
protected List<SelectableConcurrentHashMap.Segment>	segments()
void	setMaxSize(long maxSize)
int	size()
Object	storedObject(Element e) Return an object of the kind which will be stored when the element is going to be inserted
Collection<Element>	values()

Methods inherited from class java.lang.Object

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

Constructor Detail

SelectableConcurrentHashMap

public SelectableConcurrentHashMap(PoolAccessor poolAccessor,
                                   int concurrency,
                                   long maximumSize,
                                   RegisteredEventListeners cacheEventNotificationService)

SelectableConcurrentHashMap

public SelectableConcurrentHashMap(PoolAccessor poolAccessor,
                                   int initialCapacity,
                                   float loadFactor,
                                   int concurrency,
                                   long maximumSize,
                                   RegisteredEventListeners cacheEventNotificationService)

Method Detail

setMaxSize

public void setMaxSize(long maxSize)

getRandomValues

public Element[] getRandomValues(int size,
                                 Object keyHint)

storedObject

public Object storedObject(Element e)

Return an object of the kind which will be stored when the element is going to be inserted

Parameters:

e - the element

Returns:

an object looking-alike the stored one

quickSize

public int quickSize()

Returns the number of key-value mappings in this map without locking anything. This may not give the exact element count as locking is avoided. If the map contains more than Integer.MAX_VALUE elements, returns Integer.MAX_VALUE.

Returns:

the number of key-value mappings in this map

isEmpty

public boolean isEmpty()

size

public int size()

lockFor

public ReentrantReadWriteLock lockFor(Object key)

locks

public ReentrantReadWriteLock[] locks()

get

public Element get(Object key)

containsKey

public boolean containsKey(Object key)

containsValue

public boolean containsValue(Object value)

put

public Element put(Object key,
                   Element element,
                   long sizeOf)

putIfAbsent

public Element putIfAbsent(Object key,
                           Element element,
                           long sizeOf)

remove

public Element remove(Object key)

remove

public boolean remove(Object key,
                      Object value)

clear

public void clear()

keySet

public Set<Object> keySet()

values

public Collection<Element> values()

entrySet

public Set<Map.Entry<Object,Element>> entrySet()

createSegment

protected SelectableConcurrentHashMap.Segment createSegment(int initialCapacity,
                                                            float lf)

evict

public boolean evict()

recalculateSize

public void recalculateSize(Object key)

segmentFor

protected final SelectableConcurrentHashMap.Segment segmentFor(int hash)

Returns the segment that should be used for key with given hash

Parameters:

hash - the hash code for the key

Returns:

the segment

segments

protected final List<SelectableConcurrentHashMap.Segment> segments()

hash

protected static int hash(int h)