org.springframework.util

Class ConcurrentReferenceHashMap.Segment

java.lang.Object

java.util.concurrent.locks.ReentrantLock

org.springframework.util.ConcurrentReferenceHashMap.Segment

All Implemented Interfaces:

java.io.Serializable, java.util.concurrent.locks.Lock

Enclosing class:

ConcurrentReferenceHashMap<K,V>

protected final class ConcurrentReferenceHashMap.Segment
extends java.util.concurrent.locks.ReentrantLock

A single segment used to divide the map to allow better concurrent performance.

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
Segment(int initialCapacity)

Method Summary

Modifier and Type	Method and Description
void	clear() Clear all items from this segment.
<T> T	doTask(int hash, java.lang.Object key, org.springframework.util.ConcurrentReferenceHashMap.Task<T> task) Apply an update operation to this segment.
int	getCount() Return the total number of references in this segment.
ConcurrentReferenceHashMap.Reference<K,V>	getReference(java.lang.Object key, int hash, ConcurrentReferenceHashMap.Restructure restructure)
int	getSize() Return the size of the current references array.
protected void	restructureIfNecessary(boolean allowResize) Restructure the underlying data structure when it becomes necessary.

Methods inherited from class java.util.concurrent.locks.ReentrantLock

getHoldCount, getOwner, getQueuedThreads, getQueueLength, getWaitingThreads, getWaitQueueLength, hasQueuedThread, hasQueuedThreads, hasWaiters, isFair, isHeldByCurrentThread, isLocked, lock, lockInterruptibly, newCondition, toString, tryLock, tryLock, unlock

Methods inherited from class java.lang.Object

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

Constructor Detail

Segment

public Segment(int initialCapacity)

Method Detail

getReference

public ConcurrentReferenceHashMap.Reference<K,V> getReference(java.lang.Object key,
                                                              int hash,
                                                              ConcurrentReferenceHashMap.Restructure restructure)

doTask

public <T> T doTask(int hash,
                    java.lang.Object key,
                    org.springframework.util.ConcurrentReferenceHashMap.Task<T> task)

Apply an update operation to this segment. The segment will be locked during the update.

Parameters:

hash - the hash of the key

key - the key

task - the update operation

Returns:

the result of the operation

clear

public void clear()

Clear all items from this segment.

restructureIfNecessary

protected final void restructureIfNecessary(boolean allowResize)

Restructure the underlying data structure when it becomes necessary. This method can increase the size of the references table as well as purge any references that have been garbage collected.

Parameters:

allowResize - if resizing is permitted

getSize

public final int getSize()

Return the size of the current references array.

getCount

public final int getCount()

Return the total number of references in this segment.