EDU.oswego.cs.dl.util.concurrent
Class SynchronousChannel
java.lang.Object
EDU.oswego.cs.dl.util.concurrent.SynchronousChannel
- BoundedChannel, Channel, Puttable, Takable
public class SynchronousChannel
extends java.lang.Object
A rendezvous channel, similar to those used in CSP and Ada. Each
put must wait for a take, and vice versa. Synchronous channels
are well suited for handoff designs, in which an object running in
one thread must synch up with an object running in another thread
in order to hand it some information, event, or task.
If you only need threads to synch up without
exchanging information, consider using a Barrier. If you need
bidirectional exchanges, consider using a Rendezvous.
[
Introduction to this package. ]
int | capacity()
|
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.
|
CANCELLED
protected static final Object CANCELLED
Special marker used in queue nodes to indicate that
the thread waiting for a change in the node has timed out
or been interrupted.
capacity
public int capacity()
- capacity in interface BoundedChannel
- zero --
Synchronous channels have no internal capacity.
offer
public boolean offer(Object x,
long msecs)
throws InterruptedException
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.
- offer in interface Channel
- offer in interface Puttable
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.
- true if accepted, else false
peek
public Object peek()
- peek in interface Channel
- null --
Synchronous channels do not hold contents unless actively taken
poll
public Object poll(long msecs)
throws InterruptedException
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.
- poll in interface Channel
- poll in interface Takable
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.
- some item, or null if the channel is empty.
put
public void put(Object x)
throws InterruptedException
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.
- put in interface Channel
- put in interface Puttable
take
public Object take()
throws InterruptedException
Return and remove an item from channel,
possibly waiting indefinitely until
such an item exists.
- take in interface Channel
- take in interface Takable
- some item from the channel. Different implementations
may guarantee various properties (such as FIFO) about that item