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ActiveMQ example source code file (RedeliveryPolicy.java)

This example ActiveMQ source code file (RedeliveryPolicy.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - ActiveMQ tags/keywords

cloneable, clonenotsupportedexception, clonenotsupportedexception, could, io, no_maximum_redeliveries, random, random, redeliverypolicy, redeliverypolicy, runtimeexception, serializable, serializable, util

The ActiveMQ RedeliveryPolicy.java source code

/**
 * 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.activemq;

import java.io.Serializable;
import java.util.Random;

/**
 * Configuration options used to control how messages are re-delivered when they
 * are rolled back.
 *
 * @org.apache.xbean.XBean element="redeliveryPolicy"
 *
 */
public class RedeliveryPolicy implements Cloneable, Serializable {

    public static final int NO_MAXIMUM_REDELIVERIES = -1;
    private static Random randomNumberGenerator;

    // +/-15% for a 30% spread -cgs
    private double collisionAvoidanceFactor = 0.15d;
    private int maximumRedeliveries = 6;
    private long maximumRedeliveryDelay = -1;
    private long initialRedeliveryDelay = 1000L;
    private boolean useCollisionAvoidance;
    private boolean useExponentialBackOff;
    private double backOffMultiplier = 5.0;
    private long redeliveryDelay = initialRedeliveryDelay;

    public RedeliveryPolicy() {
    }

    public RedeliveryPolicy copy() {
        try {
            return (RedeliveryPolicy)clone();
        } catch (CloneNotSupportedException e) {
            throw new RuntimeException("Could not clone: " + e, e);
        }
    }

    public double getBackOffMultiplier() {
        return backOffMultiplier;
    }

    public void setBackOffMultiplier(double backOffMultiplier) {
        this.backOffMultiplier = backOffMultiplier;
    }

    public short getCollisionAvoidancePercent() {
        return (short)Math.round(collisionAvoidanceFactor * 100);
    }

    public void setCollisionAvoidancePercent(short collisionAvoidancePercent) {
        this.collisionAvoidanceFactor = collisionAvoidancePercent * 0.01d;
    }

    public long getInitialRedeliveryDelay() {
        return initialRedeliveryDelay;
    }

    public void setInitialRedeliveryDelay(long initialRedeliveryDelay) {
        this.initialRedeliveryDelay = initialRedeliveryDelay;
    }

    public long getMaximumRedeliveryDelay() {
        return maximumRedeliveryDelay;
    }

    public void setMaximumRedeliveryDelay(long maximumRedeliveryDelay) {
        this.maximumRedeliveryDelay = maximumRedeliveryDelay;
    }

    public int getMaximumRedeliveries() {
        return maximumRedeliveries;
    }

    public void setMaximumRedeliveries(int maximumRedeliveries) {
        this.maximumRedeliveries = maximumRedeliveries;
    }

    public long getNextRedeliveryDelay(long previousDelay) {
        long nextDelay;

        if (previousDelay == 0) {
            nextDelay = redeliveryDelay;
        } else if (useExponentialBackOff && backOffMultiplier > 1) {
            nextDelay = (long) (previousDelay * backOffMultiplier);
            if(maximumRedeliveryDelay != -1 && nextDelay > maximumRedeliveryDelay) {
                // in case the user made max redelivery delay less than redelivery delay for some reason.
                nextDelay = Math.max(maximumRedeliveryDelay, redeliveryDelay);
            }
        } else {
            nextDelay = previousDelay;
        }

        if (useCollisionAvoidance) {
            /*
             * First random determines +/-, second random determines how far to
             * go in that direction. -cgs
             */
            Random random = getRandomNumberGenerator();
            double variance = (random.nextBoolean() ? collisionAvoidanceFactor : -collisionAvoidanceFactor) * random.nextDouble();
            nextDelay += nextDelay * variance;
        }

        return nextDelay;
    }

    public boolean isUseCollisionAvoidance() {
        return useCollisionAvoidance;
    }

    public void setUseCollisionAvoidance(boolean useCollisionAvoidance) {
        this.useCollisionAvoidance = useCollisionAvoidance;
    }

    public boolean isUseExponentialBackOff() {
        return useExponentialBackOff;
    }

    public void setUseExponentialBackOff(boolean useExponentialBackOff) {
        this.useExponentialBackOff = useExponentialBackOff;
    }

    protected static synchronized Random getRandomNumberGenerator() {
        if (randomNumberGenerator == null) {
            randomNumberGenerator = new Random();
        }
        return randomNumberGenerator;
    }

    public void setRedeliveryDelay(long redeliveryDelay) {
        this.redeliveryDelay = redeliveryDelay;
    }

    public long getRedeliveryDelay() {
        return redeliveryDelay;
    }
}

Other ActiveMQ examples (source code examples)

Here is a short list of links related to this ActiveMQ RedeliveryPolicy.java source code file:

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