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/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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.apache.pulsar.client.impl;
import static com.google.common.base.Preconditions.checkArgument;
import org.apache.pulsar.client.api.RedeliveryBackoff;
/**
* MultiplierRedeliveryBackoff.
*/
public class MultiplierRedeliveryBackoff implements RedeliveryBackoff {
private final long minDelayMs;
private final long maxDelayMs;
private final double multiplier;
private final int maxMultiplierPow;
private MultiplierRedeliveryBackoff(long minDelayMs, long maxDelayMs, double multiplier) {
this.minDelayMs = minDelayMs;
this.maxDelayMs = maxDelayMs;
this.multiplier = multiplier;
maxMultiplierPow = (int) (Math.log((double) maxDelayMs / minDelayMs) / Math.log(multiplier)) + 1;
}
public static MultiplierRedeliveryBackoff.MultiplierRedeliveryBackoffBuilder builder() {
return new MultiplierRedeliveryBackoff.MultiplierRedeliveryBackoffBuilder();
}
@Override
public long next(int redeliveryCount) {
if (redeliveryCount <= 0 || minDelayMs <= 0) {
return this.minDelayMs;
}
if (redeliveryCount > maxMultiplierPow) {
return this.maxDelayMs;
}
return Math.min((long) (minDelayMs * Math.pow(multiplier, redeliveryCount)), this.maxDelayMs);
}
/**
* Builder of MultiplierRedeliveryBackoff.
*/
public static class MultiplierRedeliveryBackoffBuilder {
private long minDelayMs = 1000 * 10;
private long maxDelayMs = 1000 * 60 * 10;
private double multiplier = 2.0;
public MultiplierRedeliveryBackoffBuilder minDelayMs(long minDelayMs) {
this.minDelayMs = minDelayMs;
return this;
}
public MultiplierRedeliveryBackoffBuilder maxDelayMs(long maxDelayMs) {
this.maxDelayMs = maxDelayMs;
return this;
}
public MultiplierRedeliveryBackoffBuilder multiplier(double multiplier) {
this.multiplier = multiplier;
return this;
}
public MultiplierRedeliveryBackoff build() {
checkArgument(minDelayMs >= 0, "min delay time must be >= 0");
checkArgument(maxDelayMs >= minDelayMs, "maxDelayMs must be >= minDelayMs");
checkArgument(multiplier > 1, "multiplier must be > 1");
return new MultiplierRedeliveryBackoff(minDelayMs, maxDelayMs, multiplier);
}
}
}