public class MpmcArrayQueue<E>
extends java.util.AbstractQueue<E>
ConcurrentCircularArrayQueue
. This
implies that any and all threads may call the offer/poll/peek methods and correctness is maintained. Tradeoffs to keep in mind:
MessagePassingQueue.Consumer<T>, MessagePassingQueue.ExitCondition, MessagePassingQueue.Supplier<T>, MessagePassingQueue.WaitStrategy
限定符和类型 | 字段和说明 |
---|---|
protected E[] |
buffer |
protected long |
mask |
static int |
MAX_LOOK_AHEAD_STEP |
protected long[] |
sequenceBuffer |
UNBOUNDED_CAPACITY
构造器和说明 |
---|
MpmcArrayQueue(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 |
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. |
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() |
contains, containsAll, remove, removeAll, retainAll, toArray, toArray
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
public static final int MAX_LOOK_AHEAD_STEP
protected final long[] sequenceBuffer
protected final long mask
protected final E[] buffer
public boolean offer(E e)
MessagePassingQueue
Queue.offer(Object)
interface.e
- not null
, will throw NPE if it ispublic E poll()
Queue.poll()
interface.
Because return null indicates queue is empty we cannot simply rely on next element visibility for poll and must test producer index when next element is not visible.
null
iff emptypublic E peek()
MessagePassingQueue
Queue.peek()
interface.null
iff emptypublic 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.
public final long lvConsumerIndex()
public final long lvProducerIndex()
public int size()
MessagePassingQueue
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 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 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 int capacity()
capacity
在接口中 MessagePassingQueue<E>
MessagePassingQueue.UNBOUNDED_CAPACITY
if not boundedpublic long currentProducerIndex()
QueueProgressIndicators
currentProducerIndex
在接口中 QueueProgressIndicators
public long currentConsumerIndex()
QueueProgressIndicators
currentConsumerIndex
在接口中 QueueProgressIndicators
public 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>