Interface MessagePassingQueue<T>
- Type Parameters:
T
- the event/message type
- All Known Implementing Classes:
AtomicReferenceArrayQueue
,BaseLinkedAtomicQueue
,BaseLinkedAtomicQueueConsumerNodeRef
,BaseLinkedAtomicQueuePad0
,BaseLinkedAtomicQueuePad1
,BaseLinkedAtomicQueuePad2
,BaseLinkedAtomicQueueProducerNodeRef
,BaseLinkedQueue
,BaseLinkedQueueConsumerNodeRef
,BaseLinkedQueuePad0
,BaseLinkedQueuePad1
,BaseLinkedQueuePad2
,BaseLinkedQueueProducerNodeRef
,BaseMpscLinkedArrayQueue
,BaseMpscLinkedAtomicArrayQueue
,BaseSpscLinkedArrayQueue
,BaseSpscLinkedAtomicArrayQueue
,ConcurrentCircularArrayQueue
,ConcurrentSequencedCircularArrayQueue
,FFBuffer
,FFBufferConsumerField
,FFBufferL1Pad
,FFBufferL2Pad
,FFBufferL3Pad
,FFBufferProducerField
,MpmcArrayQueue
,MpmcArrayQueueConsumerIndexField
,MpmcArrayQueueL1Pad
,MpmcArrayQueueL2Pad
,MpmcArrayQueueL3Pad
,MpmcArrayQueueProducerIndexField
,MpmcAtomicArrayQueue
,MpmcAtomicArrayQueueConsumerIndexField
,MpmcAtomicArrayQueueL1Pad
,MpmcAtomicArrayQueueL2Pad
,MpmcAtomicArrayQueueL3Pad
,MpmcAtomicArrayQueueProducerIndexField
,MpmcUnboundedXaddArrayQueue
,MpscArrayQueue
,MpscArrayQueueConsumerIndexField
,MpscArrayQueueL1Pad
,MpscArrayQueueL2Pad
,MpscArrayQueueL3Pad
,MpscArrayQueueMidPad
,MpscArrayQueueProducerIndexField
,MpscArrayQueueProducerLimitField
,MpscAtomicArrayQueue
,MpscAtomicArrayQueueConsumerIndexField
,MpscAtomicArrayQueueL1Pad
,MpscAtomicArrayQueueL2Pad
,MpscAtomicArrayQueueL3Pad
,MpscAtomicArrayQueueMidPad
,MpscAtomicArrayQueueProducerIndexField
,MpscAtomicArrayQueueProducerLimitField
,MpscBlockingConsumerArrayQueue
,MpscChunkedArrayQueue
,MpscChunkedArrayQueueColdProducerFields
,MpscChunkedAtomicArrayQueue
,MpscChunkedAtomicArrayQueueColdProducerFields
,MpscCompoundQueue
,MpscCompoundQueueColdFields
,MpscCompoundQueueConsumerQueueIndex
,MpscCompoundQueueL0Pad
,MpscCompoundQueueMidPad
,MpscGrowableArrayQueue
,MpscGrowableAtomicArrayQueue
,MpscLinkedAtomicQueue
,MpscLinkedQueue
,MpscRelaxedArrayQueue
,MpscRelaxedAtomicArrayQueue
,MpscSequencedArrayQueue
,MpscSequencedArrayQueueConsumerField
,MpscSequencedArrayQueueL1Pad
,MpscSequencedArrayQueueL2Pad
,MpscSequencedArrayQueueProducerField
,MpscUnboundedArrayQueue
,MpscUnboundedAtomicArrayQueue
,MpscUnboundedXaddArrayQueue
,MpUnboundedXaddArrayQueue
,SequencedAtomicReferenceArrayQueue
,SpmcArrayQueue
,SpmcArrayQueueConsumerIndexField
,SpmcArrayQueueL1Pad
,SpmcArrayQueueL2Pad
,SpmcArrayQueueL3Pad
,SpmcArrayQueueMidPad
,SpmcArrayQueueProducerIndexCacheField
,SpmcArrayQueueProducerIndexField
,SpmcAtomicArrayQueue
,SpmcAtomicArrayQueueConsumerIndexField
,SpmcAtomicArrayQueueL1Pad
,SpmcAtomicArrayQueueL2Pad
,SpmcAtomicArrayQueueL3Pad
,SpmcAtomicArrayQueueMidPad
,SpmcAtomicArrayQueueProducerIndexCacheField
,SpmcAtomicArrayQueueProducerIndexField
,SpscArrayQueue
,SpscArrayQueueColdField
,SpscArrayQueueConsumerIndexField
,SpscArrayQueueL1Pad
,SpscArrayQueueL2Pad
,SpscArrayQueueL3Pad
,SpscArrayQueueProducerIndexFields
,SpscAtomicArrayQueue
,SpscAtomicArrayQueueColdField
,SpscAtomicArrayQueueConsumerIndexField
,SpscAtomicArrayQueueL1Pad
,SpscAtomicArrayQueueL2Pad
,SpscAtomicArrayQueueL3Pad
,SpscAtomicArrayQueueProducerIndexFields
,SpscChunkedArrayQueue
,SpscChunkedAtomicArrayQueue
,SpscGrowableArrayQueue
,SpscGrowableAtomicArrayQueue
,SpscLinkedAtomicQueue
,SpscLinkedQueue
,SpscUnboundedArrayQueue
,SpscUnboundedAtomicArrayQueue
Queue
methods are provided
with the same semantics, while further functionality which accomodates the concurrent usecase is also on offer.
Message passing queues provide happens before semantics to messages passed through, namely that writes made by the producer before offering the message are visible to the consuming thread after the message has been polled out of the queue.
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Nested Class Summary
Nested ClassesModifier and TypeInterfaceDescriptionstatic interface
static interface
static interface
static interface
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Field Summary
Fields -
Method Summary
Modifier and TypeMethodDescriptionint
capacity()
void
clear()
Removes all items from the queue.int
Remove all available item from the queue and hand to consume.int
drain
(MessagePassingQueue.Consumer<T> c, int limit) Remove up to limit elements from the queue and hand to consume.void
drain
(MessagePassingQueue.Consumer<T> c, MessagePassingQueue.WaitStrategy wait, MessagePassingQueue.ExitCondition exit) Remove elements from the queue and hand to consume forever.int
Stuff the queue with elements from the supplier.int
fill
(MessagePassingQueue.Supplier<T> s, int limit) Stuff the queue with up to limit elements from the supplier.void
fill
(MessagePassingQueue.Supplier<T> s, MessagePassingQueue.WaitStrategy wait, MessagePassingQueue.ExitCondition exit) Stuff the queue with elements from the supplier forever.boolean
isEmpty()
This method's accuracy is subject to concurrent modifications happening as the observation is carried out.boolean
Called from a producer thread subject to the restrictions appropriate to the implementation and according to theQueue.offer(Object)
interface.peek()
Called from the consumer thread subject to the restrictions appropriate to the implementation and according to theQueue.peek()
interface.poll()
Called from the consumer thread subject to the restrictions appropriate to the implementation and according to theQueue.poll()
interface.boolean
relaxedOffer
(T e) Called from a producer thread subject to the restrictions appropriate to the implementation.Called from the consumer thread subject to the restrictions appropriate to the implementation.Called from the consumer thread subject to the restrictions appropriate to the implementation.int
size()
This method's accuracy is subject to concurrent modifications happening as the size is estimated and as such is a best effort rather than absolute value.
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Field Details
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UNBOUNDED_CAPACITY
static final int UNBOUNDED_CAPACITY- See Also:
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Method Details
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offer
Called from a producer thread subject to the restrictions appropriate to the implementation and according to theQueue.offer(Object)
interface.- Parameters:
e
- notnull
, will throw NPE if it is- Returns:
- true if element was inserted into the queue, false iff full
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poll
T poll()Called from the consumer thread subject to the restrictions appropriate to the implementation and according to theQueue.poll()
interface.- Returns:
- a message from the queue if one is available,
null
iff empty
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peek
T peek()Called from the consumer thread subject to the restrictions appropriate to the implementation and according to theQueue.peek()
interface.- Returns:
- a message from the queue if one is available,
null
iff empty
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size
int size()This method's accuracy is subject to concurrent modifications happening as the size is estimated and as such is a best effort rather than absolute value. For some implementations this method may be O(n) rather than O(1).- Returns:
- number of messages in the queue, between 0 and
Integer.MAX_VALUE
but less or equals to capacity (if bounded).
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clear
void clear()Removes all items from the queue. Called from the consumer thread subject to the restrictions appropriate to the implementation and according to theCollection.clear()
interface. -
isEmpty
boolean isEmpty()This method's accuracy is subject to concurrent modifications happening as the observation is carried out.- Returns:
- true if empty, false otherwise
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capacity
int capacity()- Returns:
- the capacity of this queue or
UNBOUNDED_CAPACITY
if not bounded
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relaxedOffer
Called from a producer thread subject to the restrictions appropriate to the implementation. As opposed toQueue.offer(Object)
this method may return false without the queue being full.- Parameters:
e
- notnull
, will throw NPE if it is- Returns:
- true if element was inserted into the queue, false if unable to offer
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relaxedPoll
T relaxedPoll()Called from the consumer thread subject to the restrictions appropriate to the implementation. As opposed toQueue.poll()
this method may returnnull
without the queue being empty.- Returns:
- a message from the queue if one is available,
null
if unable to poll
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relaxedPeek
T relaxedPeek()Called from the consumer thread subject to the restrictions appropriate to the implementation. As opposed toQueue.peek()
this method may returnnull
without the queue being empty.- Returns:
- a message from the queue if one is available,
null
if unable to peek
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drain
Remove up to limit elements from the queue and hand to consume. This should be semantically similar to:M m; int i = 0; for(;i < limit && (m = relaxedPoll()) != null; i++){ c.accept(m); } return i;
There's no strong commitment to the queue being empty at the end of a drain. Called from a consumer thread subject to the restrictions appropriate to the implementation.
WARNING: Explicit assumptions are made with regards to
MessagePassingQueue.Consumer.accept(T)
make sure you have read and understood these before using this method.- Returns:
- the number of polled elements
- Throws:
IllegalArgumentException
- c isnull
IllegalArgumentException
- if limit is negative
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fill
Stuff the queue with up to limit elements from the supplier. Semantically similar to:for(int i=0; i < limit && relaxedOffer(s.get()); i++);
There's no strong commitment to the queue being full at the end of a fill. Called from a producer thread subject to the restrictions appropriate to the implementation. WARNING: Explicit assumptions are made with regards to
MessagePassingQueue.Supplier.get()
make sure you have read and understood these before using this method.- Returns:
- the number of offered elements
- Throws:
IllegalArgumentException
- s isnull
IllegalArgumentException
- if limit is negative
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drain
Remove all available item from the queue and hand to consume. This should be semantically similar to:M m; while((m = relaxedPoll()) != null){ c.accept(m); }
There's no strong commitment to the queue being empty at the end of a drain. Called from a consumer thread subject to the restrictions appropriate to the implementation.WARNING: Explicit assumptions are made with regards to
MessagePassingQueue.Consumer.accept(T)
make sure you have read and understood these before using this method.- Returns:
- the number of polled elements
- Throws:
IllegalArgumentException
- c isnull
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fill
Stuff the queue with elements from the supplier. Semantically similar to:while(relaxedOffer(s.get());
There's no strong commitment to the queue being full at the end of a fill. Called from a producer thread subject to the restrictions appropriate to the implementation.Unbounded queues will fill up the queue with a fixed amount rather than fill up to oblivion. WARNING: Explicit assumptions are made with regards to
MessagePassingQueue.Supplier.get()
make sure you have read and understood these before using this method.- Returns:
- the number of offered elements
- Throws:
IllegalArgumentException
- s isnull
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drain
void drain(MessagePassingQueue.Consumer<T> c, MessagePassingQueue.WaitStrategy wait, MessagePassingQueue.ExitCondition exit) Remove elements from the queue and hand to consume forever. Semantically similar to:int idleCounter = 0; while (exit.keepRunning()) { E e = relaxedPoll(); if(e==null){ idleCounter = wait.idle(idleCounter); continue; } idleCounter = 0; c.accept(e); }
Called from a consumer thread subject to the restrictions appropriate to the implementation.
WARNING: Explicit assumptions are made with regards to
MessagePassingQueue.Consumer.accept(T)
make sure you have read and understood these before using this method.- Throws:
IllegalArgumentException
- c OR wait OR exit arenull
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fill
void fill(MessagePassingQueue.Supplier<T> s, MessagePassingQueue.WaitStrategy wait, MessagePassingQueue.ExitCondition exit) Stuff the queue with elements from the supplier forever. Semantically similar to:int idleCounter = 0; while (exit.keepRunning()) { E e = s.get(); while (!relaxedOffer(e)) { idleCounter = wait.idle(idleCounter); continue; } idleCounter = 0; }
Called from a producer thread subject to the restrictions appropriate to the implementation. The main difference being that implementors MUST assure room in the queue is available BEFORE calling
MessagePassingQueue.Supplier.get()
. WARNING: Explicit assumptions are made with regards toMessagePassingQueue.Supplier.get()
make sure you have read and understood these before using this method.- Throws:
IllegalArgumentException
- s OR wait OR exit arenull
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