public class MpscAtomicArrayQueue<E>
extends java.util.AbstractQueue<E>
ConcurrentCircularArrayQueue
. This
implies that any thread may call the offer method, but only a single thread may call poll/peek for correctness to
maintained. MessagePassingQueue.Consumer<T>, MessagePassingQueue.ExitCondition, MessagePassingQueue.Supplier<T>, MessagePassingQueue.WaitStrategy
限定符和类型 | 字段和说明 |
---|---|
protected java.util.concurrent.atomic.AtomicReferenceArray<E> |
buffer |
protected int |
mask |
UNBOUNDED_CAPACITY
构造器和说明 |
---|
MpscAtomicArrayQueue(int capacity) |
限定符和类型 | 方法和说明 |
---|---|
int |
capacity() |
void |
clear()
Removes all items from the queue.
|
long |
currentConsumerIndex()
This method has no concurrent visibility semantics.
|
long |
currentProducerIndex()
This method has no concurrent visibility semantics.
|
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 w,
MessagePassingQueue.ExitCondition exit)
Remove elements from the queue and hand to consume forever.
|
int |
failFastOffer(E e)
A wait free alternative to offer which fails on CAS failure.
|
int |
fill(MessagePassingQueue.Supplier<E> s)
Stuff the queue with elements from the supplier.
|
int |
fill(MessagePassingQueue.Supplier<E> s,
int limit)
Stuff the queue with up to limit elements from the supplier.
|
void |
fill(MessagePassingQueue.Supplier<E> 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.
|
java.util.Iterator<E> |
iterator()
Get an iterator for this queue.
|
long |
lvConsumerIndex() |
long |
lvProducerIndex() |
boolean |
offer(E e)
Called from a producer thread subject to the restrictions appropriate to the implementation and
according to the
Queue.offer(Object) interface. |
boolean |
offerIfBelowThreshold(E e,
int threshold)
|
E |
peek()
Called from the consumer thread subject to the restrictions appropriate to the implementation and
according to the
Queue.peek() interface. |
E |
poll()
Called from the consumer thread subject to the restrictions appropriate to the implementation and
according to the
Queue.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.
|
java.lang.String |
toString() |
int |
weakOffer(E e)
已过时。
This was renamed to failFastOffer please migrate
|
contains, containsAll, remove, removeAll, retainAll, toArray, toArray
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
protected final java.util.concurrent.atomic.AtomicReferenceArray<E> buffer
protected final int mask
public boolean offerIfBelowThreshold(E e, int threshold)
e
- the object to offer onto the queue, not nullthreshold
- the maximum allowable sizepublic boolean offer(E e)
Queue.offer(Object)
interface.
IMPLEMENTATION NOTES:
Lock free offer using a single CAS. As class name suggests access is permitted to many threads
concurrently.
e
- not null
, will throw NPE if it isQueue.offer(E)
,
MessagePassingQueue.offer(T)
public final int failFastOffer(E e)
e
- new element, not nullpublic E poll()
Queue.poll()
interface.
IMPLEMENTATION NOTES:
Lock free poll using ordered loads/stores. As class name suggests access is limited to a single thread.
null
iff emptyQueue.poll()
,
MessagePassingQueue.poll()
public E peek()
Queue.peek()
interface.
IMPLEMENTATION NOTES:
Lock free peek using ordered loads. As class name suggests access is limited to a single thread.
null
iff emptyQueue.poll()
,
MessagePassingQueue.poll()
public boolean relaxedOffer(E e)
MessagePassingQueue
Queue.offer(Object)
this method may return false without the queue being full.e
- not null
, will throw NPE if it ispublic E relaxedPoll()
MessagePassingQueue
Queue.poll()
this method may return null
without the queue being empty.null
if unable to pollpublic E relaxedPeek()
MessagePassingQueue
Queue.peek()
this method may return null
without the queue being empty.null
if unable to peekpublic int drain(MessagePassingQueue.Consumer<E> c, int limit)
MessagePassingQueue
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.
public int fill(MessagePassingQueue.Supplier<E> s, int limit)
MessagePassingQueue
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.
public int drain(MessagePassingQueue.Consumer<E> c)
MessagePassingQueue
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.
public int fill(MessagePassingQueue.Supplier<E> s)
MessagePassingQueue
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.
public void drain(MessagePassingQueue.Consumer<E> c, MessagePassingQueue.WaitStrategy w, MessagePassingQueue.ExitCondition exit)
MessagePassingQueue
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.
public void fill(MessagePassingQueue.Supplier<E> s, MessagePassingQueue.WaitStrategy wait, MessagePassingQueue.ExitCondition exit)
MessagePassingQueue
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 to MessagePassingQueue.Supplier.get()
make sure you have read
and understood these before using this method.
@Deprecated public int weakOffer(E e)
public final long lvConsumerIndex()
public final long lvProducerIndex()
public java.lang.String toString()
toString
在类中 java.util.AbstractCollection<E>
public void clear()
MessagePassingQueue
Collection.clear()
interface.clear
在接口中 MessagePassingQueue<E>
clear
在接口中 java.util.Collection<E>
clear
在类中 java.util.AbstractQueue<E>
public final int capacity()
capacity
在接口中 MessagePassingQueue<E>
MessagePassingQueue.UNBOUNDED_CAPACITY
if not boundedpublic final int size()
size
在接口中 MessagePassingQueue<E>
size
在接口中 java.util.Collection<E>
size
在类中 java.util.AbstractCollection<E>
Integer.MAX_VALUE
but less or equals to
capacity (if bounded).public final boolean isEmpty()
MessagePassingQueue
isEmpty
在接口中 MessagePassingQueue<E>
isEmpty
在接口中 java.util.Collection<E>
isEmpty
在类中 java.util.AbstractCollection<E>
public final long currentProducerIndex()
QueueProgressIndicators
currentProducerIndex
在接口中 QueueProgressIndicators
public final long currentConsumerIndex()
QueueProgressIndicators
currentConsumerIndex
在接口中 QueueProgressIndicators
public final java.util.Iterator<E> iterator()
The iterator provides a best-effort snapshot of the elements in the queue. The returned iterator is not guaranteed to return elements in queue order, and races with the consumer thread may cause gaps in the sequence of returned elements. Like {link #relaxedPoll}, the iterator may not immediately return newly inserted elements.
iterator
在接口中 java.lang.Iterable<E>
iterator
在接口中 java.util.Collection<E>
iterator
在类中 java.util.AbstractCollection<E>