Package EDU.oswego.cs.dl.util.concurrent
Class BoundedBuffer
java.lang.Object
EDU.oswego.cs.dl.util.concurrent.BoundedBuffer
- All Implemented Interfaces:
BoundedChannel
,Channel
,Puttable
,Takable
Efficient array-based bounded buffer class.
Adapted from CPJ, chapter 8, which describes design.
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Field Summary
Fields -
Constructor Summary
ConstructorsConstructorDescriptionCreate a buffer with the current default capacityBoundedBuffer
(int capacity) Create a BoundedBuffer with the given capacity. -
Method Summary
Modifier and TypeMethodDescriptionint
capacity()
Return the maximum number of elements that can be held.protected final Object
extract()
protected void
protected void
protected final void
boolean
Place item in channel only if it can be accepted within msecs milliseconds.peek()
Return, but do not remove object at head of Channel, or null if it is empty.poll
(long msecs) Return and remove an item from channel only if one is available within msecs milliseconds.void
Place item in the channel, possibly waiting indefinitely until it can be accepted.int
size()
Return the number of elements in the buffer.take()
Return and remove an item from channel, possibly waiting indefinitely until such an item exists.
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Field Details
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array_
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takePtr_
protected int takePtr_ -
putPtr_
protected int putPtr_ -
usedSlots_
protected int usedSlots_ -
emptySlots_
protected int emptySlots_ -
putMonitor_
Helper monitor to handle puts.
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Constructor Details
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BoundedBuffer
Create a BoundedBuffer with the given capacity.- Throws:
IllegalArgumentException
- if capacity less or equal to zero
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BoundedBuffer
public BoundedBuffer()Create a buffer with the current default capacity
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Method Details
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size
public int size()Return the number of elements in the buffer. This is only a snapshot value, that may change immediately after returning. -
capacity
public int capacity()Description copied from interface:BoundedChannel
Return the maximum number of elements that can be held.- Specified by:
capacity
in interfaceBoundedChannel
- Returns:
- the capacity of this channel.
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incEmptySlots
protected void incEmptySlots() -
incUsedSlots
protected void incUsedSlots() -
insert
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extract
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peek
Description copied from interface:Channel
Return, but do not remove object at head of Channel, or null if it is empty. -
put
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 interfaceChannel
- Specified by:
put
in interfacePuttable
- Parameters:
x
- 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.
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offer
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 interfaceChannel
- Specified by:
offer
in interfacePuttable
- Parameters:
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.- 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).
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take
Description copied from interface:Channel
Return and remove an item from channel, possibly waiting indefinitely until such an item exists.- Specified by:
take
in interfaceChannel
- Specified by:
take
in interfaceTakable
- 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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poll
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 interfaceChannel
- Specified by:
poll
in interfaceTakable
- 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 null return).
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