EDU.oswego.cs.dl.util.concurrent
Class SemaphoreControlledChannel
java.lang.Object
EDU.oswego.cs.dl.util.concurrent.SemaphoreControlledChannel
- BoundedChannel, Channel, Puttable, Takable
public abstract class SemaphoreControlledChannel
extends java.lang.Object
SemaphoreControlledChannel(int capacity) - Create a channel with the given capacity and default
semaphore implementation
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SemaphoreControlledChannel(int capacity, Class semaphoreClass) - Create a channel with the given capacity and
semaphore implementations instantiated from the supplied class
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int | capacity() - Return the maximum number of elements that can be held.
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protected abstract Object | extract() - Internal mechanics of take.
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protected abstract void | insert(Object x) - Internal mechanics of put.
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boolean | offer(Object x, long msecs) - Place item in channel only if it can be accepted within
msecs milliseconds.
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Object | poll(long msecs) - Return and remove an item from channel only if one is available within
msecs milliseconds.
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void | put(Object x) - Place item in the channel, possibly waiting indefinitely until
it can be accepted.
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int | size() - Return the number of elements in the buffer.
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Object | take() - Return and remove an item from channel,
possibly waiting indefinitely until
such an item exists.
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capacity_
protected int capacity_
takeGuard_
protected final Semaphore takeGuard_
SemaphoreControlledChannel
public SemaphoreControlledChannel(int capacity)
throws IllegalArgumentException
Create a channel with the given capacity and default
semaphore implementation
SemaphoreControlledChannel
public SemaphoreControlledChannel(int capacity,
Class semaphoreClass)
throws IllegalArgumentException,
NoSuchMethodException,
SecurityException,
InstantiationException,
IllegalAccessException,
InvocationTargetException
Create a channel with the given capacity and
semaphore implementations instantiated from the supplied class
capacity
public int capacity()
Return the maximum number of elements that can be held.
- capacity in interface BoundedChannel
- the capacity of this channel.
extract
protected abstract Object extract()
Internal mechanics of take.
insert
protected abstract void insert(Object x)
Internal mechanics of put.
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
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
size
public int size()
Return the number of elements in the buffer.
This is only a snapshot value, that may change
immediately after returning.
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