com.metamx.emitter.core.EmittedBatchCounter Maven / Gradle / Ivy
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/*
* Copyright 2017 Metamarkets Group Inc.
*
* 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.metamx.emitter.core;
import java.util.concurrent.Phaser;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;
final class EmittedBatchCounter
{
/**
* Max {@link Phaser}'s phase, specified in it's javadoc. Then it wraps to zero.
*/
private static final int MAX_PHASE = Integer.MAX_VALUE;
static int nextBatchNumber(int prevBatchNumber)
{
return (prevBatchNumber + 1) & MAX_PHASE;
}
private final Phaser phaser = new Phaser(1);
void batchEmitted()
{
phaser.arrive();
}
void awaitBatchEmitted(int batchNumberToAwait, long timeout, TimeUnit unit)
throws InterruptedException, TimeoutException
{
batchNumberToAwait &= MAX_PHASE;
int currentBatch = phaser.getPhase();
checkNotTerminated(currentBatch);
while (comparePhases(batchNumberToAwait, currentBatch) >= 0) {
currentBatch = phaser.awaitAdvanceInterruptibly(currentBatch, timeout, unit);
checkNotTerminated(currentBatch);
}
}
private static int comparePhases(int phase1, int phase2)
{
int diff = (phase1 - phase2) & MAX_PHASE;
if (diff == 0) {
return 0;
}
return diff < MAX_PHASE / 2 ? 1 : -1;
}
private void checkNotTerminated(int phase)
{
if (phase < 0) {
throw new IllegalStateException("Phaser[" + phaser + "] unexpectedly terminated.");
}
}
}