Class BaseLinkedQueue<E>
- All Implemented Interfaces:
Iterable<E>
,Collection<E>
,Queue<E>
,MessagePassingQueue<E>
- Direct Known Subclasses:
MpscLinkedQueue
,SpscLinkedQueue
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Nested Class Summary
Nested classes/interfaces inherited from interface org.jctools.queues.MessagePassingQueue
MessagePassingQueue.Consumer<T>, MessagePassingQueue.ExitCondition, MessagePassingQueue.Supplier<T>, MessagePassingQueue.WaitStrategy
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Field Summary
Fields inherited from class org.jctools.queues.BaseLinkedQueuePad2
b000, b001, b002, b003, b004, b005, b006, b007, b010, b011, b012, b013, b014, b015, b016, b017, b020, b021, b022, b023, b024, b025, b026, b027, b030, b031, b032, b033, b034, b035, b036, b037, b040, b041, b042, b043, b044, b045, b046, b047, b050, b051, b052, b053, b054, b055, b056, b057, b060, b061, b062, b063, b064, b065, b066, b067, b070, b071, b072, b073, b074, b075, b076, b077, b100, b101, b102, b103, b104, b105, b106, b107, b110, b111, b112, b113, b114, b115, b116, b117, b120, b121, b122, b123, b124, b125, b126, b127, b130, b131, b132, b133, b134, b135, b136, b137, b140, b141, b142, b143, b144, b145, b146, b147, b150, b151, b152, b153, b154, b155, b156, b157, b160, b161, b162, b163, b164, b165, b166, b167, b170, b171, b172, b173, b174, b175, b176, b177
Fields inherited from class org.jctools.queues.BaseLinkedQueueProducerNodeRef
P_NODE_OFFSET
Fields inherited from interface org.jctools.queues.MessagePassingQueue
UNBOUNDED_CAPACITY
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Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionint
capacity()
int
Remove all available item from the queue and hand to consume.int
drain
(MessagePassingQueue.Consumer<E> c, int limit) Remove up to limit elements from the queue and hand to consume.void
drain
(MessagePassingQueue.Consumer<E> c, MessagePassingQueue.WaitStrategy wait, MessagePassingQueue.ExitCondition exit) Remove elements from the queue and hand to consume forever.protected E
getSingleConsumerNodeValue
(LinkedQueueNode<E> currConsumerNode, LinkedQueueNode<E> nextNode) boolean
isEmpty()
This method's accuracy is subject to concurrent modifications happening as the observation is carried out.iterator()
protected final LinkedQueueNode
<E> newNode()
protected final LinkedQueueNode
<E> 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
(E 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.final 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.(package private) LinkedQueueNode
<E> spinWaitForNextNode
(LinkedQueueNode<E> currNode) toString()
Methods inherited from class org.jctools.queues.BaseLinkedQueueConsumerNodeRef
lpConsumerNode, lvConsumerNode, spConsumerNode
Methods inherited from class org.jctools.queues.BaseLinkedQueueProducerNodeRef
casProducerNode, lpProducerNode, lvProducerNode, soProducerNode, spProducerNode
Methods inherited from class java.util.AbstractCollection
contains, containsAll, remove, removeAll, retainAll, toArray, toArray
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
Methods inherited from interface java.util.Collection
contains, containsAll, equals, hashCode, parallelStream, remove, removeAll, removeIf, retainAll, spliterator, stream, toArray, toArray, toArray
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Constructor Details
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BaseLinkedQueue
BaseLinkedQueue()
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Method Details
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iterator
- Specified by:
iterator
in interfaceCollection<E>
- Specified by:
iterator
in interfaceIterable<E>
- Specified by:
iterator
in classAbstractCollection<E>
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toString
- Overrides:
toString
in classAbstractCollection<E>
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newNode
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newNode
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size
public final 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).
IMPLEMENTATION NOTES:
This is an O(n) operation as we run through all the nodes and count them.
The accuracy of the value returned by this method is subject to races with producer/consumer threads. In particular when racing with the consumer thread this method may under estimate the size.- Specified by:
size
in interfaceCollection<E>
- Specified by:
size
in interfaceMessagePassingQueue<E>
- Specified by:
size
in classAbstractCollection<E>
- Returns:
- number of messages in the queue, between 0 and
Integer.MAX_VALUE
but less or equals to capacity (if bounded). - See Also:
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isEmpty
public boolean isEmpty()This method's accuracy is subject to concurrent modifications happening as the observation is carried out.
IMPLEMENTATION NOTES:
Queue is empty when producerNode is the same as consumerNode. An alternative implementation would be to observe the producerNode.value is null, which also means an empty queue because only the consumerNode.value is allowed to be null.- Specified by:
isEmpty
in interfaceCollection<E>
- Specified by:
isEmpty
in interfaceMessagePassingQueue<E>
- Overrides:
isEmpty
in classAbstractCollection<E>
- Returns:
- true if empty, false otherwise
- See Also:
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getSingleConsumerNodeValue
protected E getSingleConsumerNodeValue(LinkedQueueNode<E> currConsumerNode, LinkedQueueNode<E> nextNode) -
poll
Called from the consumer thread subject to the restrictions appropriate to the implementation and according to theQueue.poll()
interface.
IMPLEMENTATION NOTES:
Poll is allowed from a SINGLE thread.
Poll is potentially blocking here as theQueue.poll()
does not allow returningnull
if the queue is not empty. This is very different from the original Vyukov guarantees. SeerelaxedPoll()
for the original semantics.
Poll readsconsumerNode.next
and:- If it is
null
AND the queue is empty returnnull
, if queue is not empty spin wait for value to become visible. - If it is not
null
set it as the consumer node and return it's now evacuated value.
null
, which is also the starting point for the queue. Becausenull
values are not allowed to be offered this is the only node with it's value set tonull
at any one time.- Returns:
- a message from the queue if one is available,
null
iff empty - See Also:
- If it is
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peek
Called from the consumer thread subject to the restrictions appropriate to the implementation and according to theQueue.peek()
interface.
IMPLEMENTATION NOTES:
Peek is allowed from a SINGLE thread.
Peek is potentially blocking here as theQueue.peek()
does not allow returningnull
if the queue is not empty. This is very different from the original Vyukov guarantees. SeerelaxedPeek()
for the original semantics.
Poll reads the next node from the consumerNode and:- If it is
null
AND the queue is empty returnnull
, if queue is not empty spin wait for value to become visible. - If it is not
null
return it's value.
- Returns:
- a message from the queue if one is available,
null
iff empty - See Also:
- If it is
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spinWaitForNextNode
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relaxedPoll
Description copied from interface:MessagePassingQueue
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
Description copied from interface:MessagePassingQueue
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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relaxedOffer
Description copied from interface:MessagePassingQueue
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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drain
Description copied from interface:MessagePassingQueue
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
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drain
Description copied from interface:MessagePassingQueue
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
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drain
public void drain(MessagePassingQueue.Consumer<E> c, MessagePassingQueue.WaitStrategy wait, MessagePassingQueue.ExitCondition exit) Description copied from interface:MessagePassingQueue
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. -
capacity
public int capacity()- Returns:
- the capacity of this queue or
MessagePassingQueue.UNBOUNDED_CAPACITY
if not bounded
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