org.springframework.retry.backoff.UniformRandomBackOffPolicy Maven / Gradle / Ivy
/*
* Copyright 2006-2014 the original author or authors.
*
* 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 org.springframework.retry.backoff;
import java.util.Random;
/**
* Implementation of {@link BackOffPolicy} that pauses for a random period of
* time before continuing. A pause is implemented using {@link Sleeper#sleep(long)}.
*
* {@link #setMinBackOffPeriod(long)} is thread-safe and it is safe to call
* {@link #setMaxBackOffPeriod(long)} during execution from multiple threads, however
* this may cause a single retry operation to have pauses of different
* intervals.
*
* @author Rob Harrop
* @author Dave Syer
*/
public class UniformRandomBackOffPolicy extends StatelessBackOffPolicy implements SleepingBackOffPolicy {
/**
* Default min back off period - 500ms.
*/
private static final long DEFAULT_BACK_OFF_MIN_PERIOD = 500L;
/**
* Default max back off period - 1500ms.
*/
private static final long DEFAULT_BACK_OFF_MAX_PERIOD = 1500L;
private volatile long minBackOffPeriod = DEFAULT_BACK_OFF_MIN_PERIOD;
private volatile long maxBackOffPeriod = DEFAULT_BACK_OFF_MAX_PERIOD;
private Random random = new Random(System.currentTimeMillis());
private Sleeper sleeper = new ThreadWaitSleeper();
public UniformRandomBackOffPolicy withSleeper(Sleeper sleeper) {
UniformRandomBackOffPolicy res = new UniformRandomBackOffPolicy();
res.setMinBackOffPeriod(minBackOffPeriod);
res.setSleeper(sleeper);
return res;
}
/**
* Public setter for the {@link Sleeper} strategy.
* @param sleeper the sleeper to set defaults to {@link ThreadWaitSleeper}.
*/
public void setSleeper(Sleeper sleeper) {
this.sleeper = sleeper;
}
/**
* Set the minimum back off period in milliseconds. Cannot be < 1. Default value
* is 500ms.
*
* @param backOffPeriod the backoff period
*/
public void setMinBackOffPeriod(long backOffPeriod) {
this.minBackOffPeriod = (backOffPeriod > 0 ? backOffPeriod : 1);
}
/**
* The minimum backoff period in milliseconds.
* @return the backoff period
*/
public long getMinBackOffPeriod() {
return minBackOffPeriod;
}
/**
* Set the maximum back off period in milliseconds. Cannot be < 1. Default value
* is 1500ms.
* @param backOffPeriod the back off period
*/
public void setMaxBackOffPeriod(long backOffPeriod) {
this.maxBackOffPeriod = (backOffPeriod > 0 ? backOffPeriod : 1);
}
/**
* The maximum backoff period in milliseconds.
* @return the backoff period
*/
public long getMaxBackOffPeriod() {
return maxBackOffPeriod;
}
/**
* Pause for the {@link #setMinBackOffPeriod(long)}.
* @throws BackOffInterruptedException if interrupted during sleep.
*/
protected void doBackOff() throws BackOffInterruptedException {
try {
long delta = maxBackOffPeriod==minBackOffPeriod ? 0 : random.nextInt((int) (maxBackOffPeriod - minBackOffPeriod));
sleeper.sleep(minBackOffPeriod + delta );
}
catch (InterruptedException e) {
throw new BackOffInterruptedException("Thread interrupted while sleeping", e);
}
}
public String toString() {
return "RandomBackOffPolicy[backOffPeriod=" + minBackOffPeriod + ", " + maxBackOffPeriod + "]";
}
}