/* * The MIT License (MIT) * * Copyright (c) 2013 Igor Konev * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to deal * in the Software without restriction, including without limitation the rights * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell * copies of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN * THE SOFTWARE. */ package akka.dispatch.disruptor; import akka.actor.ActorRef; import akka.dispatch.Envelope; import akka.dispatch.MessageQueue; import com.lmax.disruptor.AlertException; import com.lmax.disruptor.EventFactory; import com.lmax.disruptor.RingBuffer; import com.lmax.disruptor.Sequence; import com.lmax.disruptor.SequenceBarrier; import com.lmax.disruptor.TimeoutException; import com.lmax.disruptor.WaitStrategy; final class DisruptorMessageQueue implements MessageQueue, DisruptorMessageQueueSemantics { private static final EventFactory<ValueEvent> EVENT_FACTORY = new EventFactory<ValueEvent>() { @Override public ValueEvent newInstance() { return new ValueEvent(); } }; private final Sequence sequence = new Sequence(); private final RingBuffer<ValueEvent> ringBuffer; private final SequenceBarrier sequenceBarrier; private final int mask; private final Envelope[] buffer; private int head; private int tail; DisruptorMessageQueue(int bufferSize, WaitStrategy waitStrategy) { ringBuffer = RingBuffer.createMultiProducer(EVENT_FACTORY, bufferSize, waitStrategy); ringBuffer.addGatingSequences(sequence); sequenceBarrier = ringBuffer.newBarrier(); mask = bufferSize - 1; buffer = new Envelope[bufferSize]; } @Override public void enqueue(ActorRef receiver, Envelope handle) { long nextSequence = ringBuffer.next(); ringBuffer.get(nextSequence).handle = handle; ringBuffer.publish(nextSequence); } @Override public Envelope dequeue() { fill(); int h = head & mask; head++; Envelope handle = buffer[h]; buffer[h] = null; return handle; } @Override public int numberOfMessages() { return 0; } @Override public boolean hasMessages() { return head != tail || sequence.get() < sequenceBarrier.getCursor(); } @Override public void cleanUp(ActorRef owner, MessageQueue deadLetters) { while (hasMessages()) { deadLetters.enqueue(owner, dequeue()); } } private void fill() { if (head != tail) { return; } long nextSequence = sequence.get() + 1L; boolean interrupted = false; long availableSequence; try { while (true) { try { availableSequence = sequenceBarrier.waitFor(nextSequence); if (nextSequence <= availableSequence) { break; } Thread.yield(); } catch (AlertException ignored) { interrupted = true; } catch (InterruptedException ignored) { interrupted = true; } catch (TimeoutException ignored) { } } } finally { if (interrupted) { Thread.currentThread().interrupt(); } } int t = tail; do { buffer[t & mask] = ringBuffer.get(nextSequence).handle; t++; nextSequence++; } while (nextSequence <= availableSequence); tail = t; sequence.set(availableSequence); } private static final class ValueEvent { Envelope handle; } }