Class BaseLinkedAtomicQueue<E>
- java.lang.Object
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- java.util.AbstractCollection<E>
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- java.util.AbstractQueue<E>
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- org.jctools.queues.atomic.BaseLinkedAtomicQueuePad0<E>
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- org.jctools.queues.atomic.BaseLinkedAtomicQueueProducerNodeRef<E>
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- org.jctools.queues.atomic.BaseLinkedAtomicQueuePad1<E>
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- org.jctools.queues.atomic.BaseLinkedAtomicQueueConsumerNodeRef<E>
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- org.jctools.queues.atomic.BaseLinkedAtomicQueuePad2<E>
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- org.jctools.queues.atomic.BaseLinkedAtomicQueue<E>
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- All Implemented Interfaces:
java.lang.Iterable<E>
,java.util.Collection<E>
,java.util.Queue<E>
,MessagePassingQueue<E>
- Direct Known Subclasses:
MpscLinkedAtomicQueue
,SpscLinkedAtomicQueue
abstract class BaseLinkedAtomicQueue<E> extends BaseLinkedAtomicQueuePad2<E>
NOTE: This class was automatically generated by org.jctools.queues.atomic.JavaParsingAtomicLinkedQueueGenerator which can found in the jctools-build module. The original source file is BaseLinkedQueue.java. A base data structure for concurrent linked queues. For convenience also pulled in common single consumer methods since at this time there's no plan to implement MC.
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Nested Class Summary
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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
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Fields inherited from class org.jctools.queues.atomic.BaseLinkedAtomicQueuePad2
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
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Fields inherited from interface org.jctools.queues.MessagePassingQueue
UNBOUNDED_CAPACITY
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Constructor Summary
Constructors Constructor Description BaseLinkedAtomicQueue()
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description int
capacity()
int
drain(MessagePassingQueue.Consumer<E> c)
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(LinkedQueueAtomicNode<E> currConsumerNode, LinkedQueueAtomicNode<E> nextNode)
boolean
isEmpty()
This method's accuracy is subject to concurrent modifications happening as the observation is carried out.java.util.Iterator<E>
iterator()
protected LinkedQueueAtomicNode<E>
newNode()
protected LinkedQueueAtomicNode<E>
newNode(E e)
E
peek()
Called from the consumer thread subject to the restrictions appropriate to the implementation and according to theQueue.peek()
interface.E
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.E
relaxedPeek()
Called from the consumer thread subject to the restrictions appropriate to the implementation.E
relaxedPoll()
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.(package private) LinkedQueueAtomicNode<E>
spinWaitForNextNode(LinkedQueueAtomicNode<E> currNode)
java.lang.String
toString()
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Methods inherited from class org.jctools.queues.atomic.BaseLinkedAtomicQueueConsumerNodeRef
lpConsumerNode, lvConsumerNode, spConsumerNode
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Methods inherited from class org.jctools.queues.atomic.BaseLinkedAtomicQueueProducerNodeRef
casProducerNode, lpProducerNode, lvProducerNode, soProducerNode, spProducerNode, xchgProducerNode
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Methods inherited from class java.util.AbstractCollection
contains, containsAll, remove, removeAll, retainAll, toArray, toArray
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Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
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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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Method Detail
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iterator
public final java.util.Iterator<E> iterator()
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toString
public java.lang.String toString()
- Overrides:
toString
in classjava.util.AbstractCollection<E>
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newNode
protected final LinkedQueueAtomicNode<E> newNode()
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newNode
protected final LinkedQueueAtomicNode<E> newNode(E e)
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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 interfacejava.util.Collection<E>
- Specified by:
size
in interfaceMessagePassingQueue<E>
- Specified by:
size
in classjava.util.AbstractCollection<E>
- Returns:
- number of messages in the queue, between 0 and
Integer.MAX_VALUE
but less or equals to capacity (if bounded). - See Also:
Collection.size()
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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 interfacejava.util.Collection<E>
- Specified by:
isEmpty
in interfaceMessagePassingQueue<E>
- Overrides:
isEmpty
in classjava.util.AbstractCollection<E>
- Returns:
- true if empty, false otherwise
- See Also:
MessagePassingQueue.isEmpty()
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getSingleConsumerNodeValue
protected E getSingleConsumerNodeValue(LinkedQueueAtomicNode<E> currConsumerNode, LinkedQueueAtomicNode<E> nextNode)
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poll
public E 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:
MessagePassingQueue.poll()
,Queue.poll()
- If it is
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peek
public E 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:
MessagePassingQueue.peek()
,Queue.peek()
- If it is
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spinWaitForNextNode
LinkedQueueAtomicNode<E> spinWaitForNextNode(LinkedQueueAtomicNode<E> currNode)
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relaxedPoll
public E 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
public E 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
public boolean relaxedOffer(E e)
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
public int drain(MessagePassingQueue.Consumer<E> c, int limit)
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
public int drain(MessagePassingQueue.Consumer<E> c)
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.
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capacity
public int capacity()
- Returns:
- the capacity of this queue or
MessagePassingQueue.UNBOUNDED_CAPACITY
if not bounded
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