edu.oswego.cs.dl.util.concurrent
Class LinkedQueue
java.lang.Object
|
+--edu.oswego.cs.dl.util.concurrent.LinkedQueue
- All Implemented Interfaces:
- 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. ]
Method Summary |
boolean |
isEmpty()
|
boolean |
offer(Object x,
long msecs)
Place item in channel only if it can be accepted within
msecs milliseconds. |
Object |
peek()
Return, but do not remove object at head of Channel,
or null if it is empty. |
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. |
LinkedQueue
public LinkedQueue()
isEmpty
public boolean isEmpty()
offer
public boolean offer(Object x,
long msecs)
throws InterruptedException
- Description copied from interface:
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.
- Specified by:
offer
in interface Channel
- Following copied from interface:
edu.oswego.cs.dl.util.concurrent.Channel
- Parameters:
item
- 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.- Returns:
- true if accepted, else false
- Throws:
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).
peek
public Object peek()
- Description copied from interface:
Channel
- Return, but do not remove object at head of Channel,
or null if it is empty.
- Specified by:
peek
in interface Channel
poll
public Object poll(long msecs)
throws InterruptedException
- Description copied from interface:
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.
- Specified by:
poll
in interface Channel
- Following copied from interface:
edu.oswego.cs.dl.util.concurrent.Channel
- Parameters:
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.- Returns:
- some item, or null if the channel is empty.
- Throws:
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 false return).
put
public void put(Object x)
throws InterruptedException
- Description copied from interface:
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.
- Specified by:
put
in interface Channel
- Following copied from interface:
edu.oswego.cs.dl.util.concurrent.Channel
- Parameters:
item
- the element to be inserted. Should be non-null.- Throws:
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.
take
public Object take()
throws InterruptedException
- Description copied from interface:
Channel
- Return and remove an item from channel,
possibly waiting indefinitely until
such an item exists.
- Specified by:
take
in interface Channel
- Following copied from interface:
edu.oswego.cs.dl.util.concurrent.Channel
- Returns:
- some item from the channel. Different implementations
may guarantee various properties (such as FIFO) about that item
- Throws:
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.
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