程序包 cn.taketoday.util

类 ConcurrentReferenceHashMap.Segment

java.lang.Object

java.util.concurrent.locks.ReentrantLock

cn.taketoday.util.ConcurrentReferenceHashMap.Segment

所有已实现的接口:

Serializable, Lock

封闭类:

ConcurrentReferenceHashMap<K,V>

protected final class ConcurrentReferenceHashMap.Segment
extends ReentrantLock

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

另请参阅:

• 序列化表格

字段概要

字段

修饰符和类型	字段	说明
private final AtomicInteger	count	The total number of references contained in this segment.
private final int	initialSize
private final ConcurrentReferenceHashMap<K,V>.ReferenceManager	referenceManager
private ConcurrentReferenceHashMap.Reference<K,V>[]	references	Array of references indexed using the low order bits from the hash.
private int	resizeThreshold	The threshold when resizing of the references should occur.

构造器概要

构造器

构造器	说明
Segment(int initialSize, int resizeThreshold)

方法概要

修饰符和类型	方法	说明
void	clear()	Clear all items from this segment.
<T> T	doTask(int hash, Object key, ConcurrentReferenceHashMap<K,V>.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(Object key, int hash, ConcurrentReferenceHashMap.Restructure restructure)
int	getSize()	Return the size of the current references array.
private void	restructure(boolean allowResize, ConcurrentReferenceHashMap.Reference<K,V> ref)
private void	restructureIfNecessary(boolean allowResize)	Restructure the underlying data structure when it becomes necessary.

从类继承的方法 java.util.concurrent.locks.ReentrantLock

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

从类继承的方法 java.lang.Object

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

字段详细资料

referenceManager

private final ConcurrentReferenceHashMap<K,V>.ReferenceManager referenceManager

initialSize

private final int initialSize

references

private volatile ConcurrentReferenceHashMap.Reference<K,V>[] references

Array of references indexed using the low order bits from the hash. This property should only be set along with resizeThreshold.

count

private final AtomicInteger count

The total number of references contained in this segment. This includes chained references and references that have been garbage collected but not purged.

resizeThreshold

private int resizeThreshold

The threshold when resizing of the references should occur. When count exceeds this value references will be resized.

构造器详细资料

Segment

public Segment(int initialSize,
 int resizeThreshold)

方法详细资料

getReference

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

doTask

@Nullable
public <T> T doTask(int hash,
 @Nullable
 Object key,
 ConcurrentReferenceHashMap<K,V>.Task<T> task)

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

参数:

hash - the hash of the key

key - the key

task - the update operation

返回:

the result of the operation

clear

public void clear()

Clear all items from this segment.

restructureIfNecessary

private 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.

参数:

allowResize - if resizing is permitted

restructure

private void restructure(boolean allowResize,
 @Nullable
 ConcurrentReferenceHashMap.Reference<K,V> ref)

getSize

public int getSize()

Return the size of the current references array.

getCount

public int getCount()

Return the total number of references in this segment.