com.lmax.disruptor.ProcessingSequenceBarrier Maven / Gradle / Ivy
/*
* Copyright 2011 LMAX Ltd.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.lmax.disruptor;
/**
* {@link SequenceBarrier} handed out for gating {@link EventProcessor}s on a cursor sequence and optional dependent {@link EventProcessor}(s),
* using the given WaitStrategy.
*/
final class ProcessingSequenceBarrier implements SequenceBarrier
{
private final WaitStrategy waitStrategy;
private final Sequence dependentSequence;
private volatile boolean alerted = false;
private final Sequence cursorSequence;
private final Sequencer sequencer;
ProcessingSequenceBarrier(
final Sequencer sequencer,
final WaitStrategy waitStrategy,
final Sequence cursorSequence,
final Sequence[] dependentSequences)
{
this.sequencer = sequencer;
this.waitStrategy = waitStrategy;
this.cursorSequence = cursorSequence;
if (0 == dependentSequences.length)
{
dependentSequence = cursorSequence;
}
else
{
dependentSequence = new FixedSequenceGroup(dependentSequences);
}
}
@Override
public long waitFor(final long sequence)
throws AlertException, InterruptedException, TimeoutException
{
checkAlert();
long availableSequence = waitStrategy.waitFor(sequence, cursorSequence, dependentSequence, this);
if (availableSequence < sequence)
{
return availableSequence;
}
return sequencer.getHighestPublishedSequence(sequence, availableSequence);
}
@Override
public long getCursor()
{
return dependentSequence.get();
}
@Override
public boolean isAlerted()
{
return alerted;
}
@Override
public void alert()
{
alerted = true;
waitStrategy.signalAllWhenBlocking();
}
@Override
public void clearAlert()
{
alerted = false;
}
@Override
public void checkAlert() throws AlertException
{
if (alerted)
{
throw AlertException.INSTANCE;
}
}
}