/*
* Copyright © 2012 The Feign Authors ([email protected])
*
* 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 feign;
import static java.util.concurrent.TimeUnit.SECONDS;
public class DefaultRetryer implements Retryer {
private final int maxAttempts;
private final long period;
private final long maxPeriod;
int attempt;
long sleptForMillis;
public DefaultRetryer() {
this(100, SECONDS.toMillis(1), 5);
}
public DefaultRetryer(long period, long maxPeriod, int maxAttempts) {
this.period = period;
this.maxPeriod = maxPeriod;
this.maxAttempts = maxAttempts;
this.attempt = 1;
}
// visible for testing;
protected long currentTimeMillis() {
return System.currentTimeMillis();
}
public void continueOrPropagate(RetryableException e) {
if (attempt++ >= maxAttempts) {
throw e;
}
long interval;
if (e.retryAfter() != null) {
interval = e.retryAfter() - currentTimeMillis();
if (interval > maxPeriod) {
interval = maxPeriod;
}
if (interval < 0) {
return;
}
} else {
interval = nextMaxInterval();
}
try {
Thread.sleep(interval);
} catch (InterruptedException ignored) {
Thread.currentThread().interrupt();
throw e;
}
sleptForMillis += interval;
}
/**
* Calculates the time interval to a retry attempt.
* The interval increases exponentially with each attempt, at a rate of nextInterval *= 1.5 (where
* 1.5 is the backoff factor), to the maximum interval.
*
* @return time in milliseconds from now until the next attempt.
*/
long nextMaxInterval() {
long interval = (long) (period * Math.pow(1.5, attempt - 1));
return Math.min(interval, maxPeriod);
}
@Override
public Retryer clone() {
return new DefaultRetryer(period, maxPeriod, maxAttempts);
}
}