mx.bigdata.utils.amqp.ReconnectingConsumer.java Source code

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Here is the source code for mx.bigdata.utils.amqp.ReconnectingConsumer.java

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/*
 *  Copyright 2010 BigData Mx
 *
 *  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 mx.bigdata.utils.amqp;

import java.io.IOException;

import com.rabbitmq.client.AMQP;
import com.rabbitmq.client.ConnectionFactory;
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Consumer;
import com.rabbitmq.client.DefaultConsumer;
import com.rabbitmq.client.Envelope;
import com.rabbitmq.client.QueueingConsumer;
import com.rabbitmq.client.ShutdownSignalException;

import org.apache.log4j.Logger;

import mx.bigdata.utils.amqp.AMQPClientHelper;

public abstract class ReconnectingConsumer {

    private final static int MAX_BACKOFF = 32 * 1000;

    private final Logger logger = Logger.getLogger(getClass());

    private final ConnectionFactory factory;

    protected final String tag;

    protected final String key;

    protected final AMQPClientHelper amqp;

    private DefaultConsumer consumer;

    private String consumerTag;

    public ReconnectingConsumer(String tag, String key, AMQPClientHelper amqp, ConnectionFactory factory) {
        this.tag = tag;
        this.key = key;
        this.amqp = amqp;
        this.factory = factory;
        initConsumer();
    }

    public ReconnectingConsumer(String tag, String key, AMQPClientHelper amqp) throws Exception {
        this(tag, key, amqp, amqp.createConnectionFactory(key));
    }

    protected abstract void handleDelivery(String consumerTag, Envelope envelope, AMQP.BasicProperties properties,
            byte[] body) throws IOException;

    protected abstract String createQueue(AMQPClientHelper amqp, Channel channel, String key) throws Exception;

    private boolean initConsumer() {
        Channel channel = null;
        try {
            channel = amqp.declareChannel(factory, key);
            String queue = createQueue(amqp, channel, key);
            this.consumer = new DefaultConsumer(channel) {

                @Override
                public void handleDelivery(String consumerTag, Envelope envelope, AMQP.BasicProperties properties,
                        byte[] body) throws IOException {
                    ReconnectingConsumer.this.handleDelivery(consumerTag, envelope, properties, body);
                }

                @Override
                public void handleConsumeOk(String consumerTag) {
                    ReconnectingConsumer.this.consumerTag = consumerTag;
                }

                @Override
                public void handleCancel(String consumerTag) throws IOException {
                    logger.warn(tag + " handleCancel for consumer tag: " + consumerTag);
                    try {
                        this.getChannel().basicCancel(ReconnectingConsumer.this.consumerTag);
                    } catch (Exception ignore) {
                    }
                    this.getChannel().getConnection().abort(5000);
                    reconnect();
                }

                @Override
                public void handleShutdownSignal(java.lang.String consumerTag, ShutdownSignalException sig) {
                    try {
                        getChannel().basicCancel(ReconnectingConsumer.this.consumerTag);
                    } catch (Exception ignore) {
                        ;
                    }
                    getChannel().getConnection().abort(5000);
                    if (!sig.isInitiatedByApplication()) {
                        logger.warn(tag + " ShutdownSignal for tag: " + tag + "\n\t consumer tag: " + consumerTag
                                + "\n\t reason: " + sig.getReason() + "\n\t reference: " + sig.getReason()
                                + "\n\t ", sig);
                        reconnect();
                    } else {
                        logger.debug(tag + " ShutdownSignal for tag: " + tag + "\n\t consumer tag: " + consumerTag
                                + "\n\t reason: " + sig.getReason() + "\n\t reference: " + sig.getReason()
                                + "\n\t ", sig);
                        consumer = null;
                    }
                }
            };

            channel.basicConsume(queue, false, consumer);
            logger.info("Consumer " + tag + " initilized");
            return true;
        } catch (Throwable e) {
            logger.error("Exception initializing consumer " + tag + ": ", e);
            if (channel != null) {
                channel.getConnection().abort(5000);
            }
        }
        return false;
    }

    protected Channel getChannel() {
        return consumer.getChannel();
    }

    private boolean reconnect() {
        return reconnect(0, 1);
    }

    private boolean reconnect(int backoff, int pow) {
        if (consumer == null) {
            return false;
        }
        try {
            if (backoff > 0) {
                logger.info("Reconnecting consumer " + tag + " in " + (backoff / 1000) + " seconds ");
                Thread.sleep(backoff);
            }
        } catch (InterruptedException ignore) {
        }
        boolean initialized = initConsumer();
        if (!initialized) {
            if (backoff >= MAX_BACKOFF) {
                backoff = MAX_BACKOFF;
            } else {
                backoff = (int) (Math.pow(2, pow));
                pow += 1;
            }
            return reconnect(backoff, pow);
        }
        return true;
    }

    public void close() {
        getChannel().getConnection().abort(5000);
    }
}