org.logicalcobwebs.concurrent

类 LinkedQueue

java.lang.Object

org.logicalcobwebs.concurrent.LinkedQueue

所有已实现的接口:

Channel, Puttable, Takable

public class LinkedQueue
extends Object
implements Channel

A linked list based channel implementation. The algorithm avoids contention between puts and takes when the queue is not empty. Normally a put and a take can proceed simultaneously. (Although it does not allow multiple concurrent puts or takes.) This class tends to perform more efficently than other Channel implementations in producer/consumer applications. [ Introduction to this package. ]

字段概要

字段

限定符和类型	字段和说明
protected LinkedNode	head_ Dummy header node of list.
protected LinkedNode	last_ The last node of list.
protected Object	putLock_ Helper monitor for managing access to last node.
protected int	waitingForTake_ The number of threads waiting for a take.

构造器概要

构造器

构造器和说明
LinkedQueue()

方法概要

限定符和类型	方法和说明
protected Object	extract() Main mechanics for take/poll
protected void	insert(Object x) Main mechanics for put/offer
boolean	isEmpty()
boolean	offer(Object x, long msecs) Place item in channel only if it can be accepted within msecs milliseconds.
Object	peek()
Object	poll(long msecs) Return and remove an item from channel only if one is available within msecs milliseconds.
void	put(Object x) Place item in the channel, possibly waiting indefinitely until it can be accepted.
Object	take() Return and remove an item from channel, possibly waiting indefinitely until such an item exists.

从类继承的方法 java.lang.Object

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

字段详细资料

head_

protected LinkedNode head_

Dummy header node of list. The first actual node, if it exists, is always at head_.next. After each take, the old first node becomes the head.

putLock_

protected final Object putLock_

Helper monitor for managing access to last node.

last_

protected LinkedNode last_

The last node of list. Put() appends to list, so modifies last_

waitingForTake_

protected int waitingForTake_

The number of threads waiting for a take. Notifications are provided in put only if greater than zero. The bookkeeping is worth it here since in reasonably balanced usages, the notifications will hardly ever be necessary, so the call overhead to notify can be eliminated.

构造器详细资料

LinkedQueue

public LinkedQueue()

方法详细资料

insert

protected void insert(Object x)

Main mechanics for put/offer

extract

protected Object extract()

Main mechanics for take/poll

put

public void put(Object x)
         throws InterruptedException

从接口复制的说明: Channel

Place item in the channel, possibly waiting indefinitely until it can be accepted. Channels implementing the BoundedChannel subinterface are generally guaranteed to block on puts upon reaching capacity, but other implementations may or may not block.

指定者:

put 在接口中 Channel

指定者:

put 在接口中 Puttable

参数:

x - the element to be inserted. Should be non-null.

抛出:

InterruptedException - if the current thread has been interrupted at a point at which interruption is detected, in which case the element is guaranteed not to be inserted. Otherwise, on normal return, the element is guaranteed to have been inserted.

offer

public boolean offer(Object x,
                     long msecs)
              throws InterruptedException

从接口复制的说明: Channel

Place item in channel only if it can be accepted within msecs milliseconds. The time bound is interpreted in a coarse-grained, best-effort fashion.

指定者:

offer 在接口中 Channel

指定者:

offer 在接口中 Puttable

参数:

x - the element to be inserted. Should be non-null.

msecs - the number of milliseconds to wait. If less than or equal to zero, the method does not perform any timed waits, but might still require access to a synchronization lock, which can impose unbounded delay if there is a lot of contention for the channel.

返回:

true if accepted, else false

抛出:

InterruptedException - if the current thread has been interrupted at a point at which interruption is detected, in which case the element is guaranteed not to be inserted (i.e., is equivalent to a false return).

take

public Object take()
            throws InterruptedException

从接口复制的说明: Channel

Return and remove an item from channel, possibly waiting indefinitely until such an item exists.

指定者:

take 在接口中 Channel

指定者:

take 在接口中 Takable

返回:

some item from the channel. Different implementations may guarantee various properties (such as FIFO) about that item

抛出:

InterruptedException - if the current thread has been interrupted at a point at which interruption is detected, in which case state of the channel is unchanged.

peek

public Object peek()

指定者:

peek 在接口中 Channel

返回:

but do not remove object at head of Channel, or null if it is empty.

isEmpty

public boolean isEmpty()

poll

public Object poll(long msecs)
            throws InterruptedException

从接口复制的说明: Channel

Return and remove an item from channel only if one is available within msecs milliseconds. The time bound is interpreted in a coarse grained, best-effort fashion.

指定者:

poll 在接口中 Channel

指定者:

poll 在接口中 Takable

参数:

msecs - the number of milliseconds to wait. If less than or equal to zero, the operation does not perform any timed waits, but might still require access to a synchronization lock, which can impose unbounded delay if there is a lot of contention for the channel.

返回:

some item, or null if the channel is empty.

抛出:

InterruptedException - if the current thread has been interrupted at a point at which interruption is detected, in which case state of the channel is unchanged (i.e., equivalent to a null return).