com.athena.sqs.MessageReceiver.java Source code

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Here is the source code for com.athena.sqs.MessageReceiver.java

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/*
 * Copyright 2012 The Athena Project
 *
 * The Athena Project licenses this file to you 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 com.athena.sqs;

import java.io.IOException;
import java.util.Date;
import java.util.List;

import javax.annotation.PostConstruct;
import javax.annotation.PreDestroy;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.DependsOn;
import org.springframework.scheduling.annotation.Async;
import org.springframework.stereotype.Service;

import com.amazonaws.services.sqs.AmazonSQSClient;
import com.amazonaws.services.sqs.model.DeleteMessageRequest;
import com.amazonaws.services.sqs.model.ReceiveMessageRequest;

/**
 * Receives message from Amazon SQS. 
 * Amazon SQS supports only polling method to retrieve the message in queues.
 * 
 * @author Ji-Woong Choi(ienvyou@gmail.com)
 *
 */
@Service
@DependsOn("messageContext")
public class MessageReceiver {
    private final Logger logger = LoggerFactory.getLogger(getClass());

    private static final long DEFAULT_POLLING_INTERVAL = 3000; // 3 seconds interval

    private long pollingFrequency;

    private @Autowired MessageContext messageContext;
    private @Autowired MessageAggregator aggregator;

    private AmazonSQSClient client;

    public MessageReceiver() {
        this(DEFAULT_POLLING_INTERVAL);
    }

    @PostConstruct
    public void initialize() {
        client = messageContext.getSqsClient();
    }

    public MessageReceiver(long pollingFrequency) {
        this.pollingFrequency = pollingFrequency;
    }

    //   @Async
    public void doReceive(String queueName) throws Exception {
        String queueUrl = messageContext.getQueue(queueName);
        logger.debug("Receiving a message to [" + queueName + "][" + queueUrl);

        // Receive messages
        ReceiveMessageRequest receiveMessageRequest = new ReceiveMessageRequest(queueUrl);

        while (true) {
            List<com.amazonaws.services.sqs.model.Message> messages = client
                    .receiveMessage(receiveMessageRequest.withMaxNumberOfMessages(10)).getMessages();
            logger.debug(new Date() + " : message count : " + messages.size());

            if (messages.size() > 0) {

                for (com.amazonaws.services.sqs.model.Message message : messages) {
                    //                   logger.debug("  Message");
                    //                   logger.debug("    MessageId:     " + message.getMessageId());
                    //                   logger.debug("    ReceiptHandle: " + message.getReceiptHandle());
                    //                   logger.debug("    MD5OfBody:     " + message.getMD5OfBody());
                    //                   logger.debug("    Body:          " + message.getBody());
                    //                   for (Entry<String, String> entry : message.getAttributes().entrySet()) {
                    //                       logger.debug("  Attribute");
                    //                       logger.debug("    Name:  " + entry.getKey());
                    //                       logger.debug("    Value: " + entry.getValue());
                    //                   }
                    logger.debug("  Message");
                    String body = message.getBody();

                    aggregator.aggregate(body);

                    client.deleteMessage(new DeleteMessageRequest(queueUrl, message.getReceiptHandle()));
                }

            } else {
                logger.debug("Nothing found, trying again in 3 seconds");
                Thread.sleep(pollingFrequency);
            }
        }
    }

    /**
     * Disconnect from sqs
     * @throws IOException
     */
    @PreDestroy
    public void doDisconnect() throws IOException {
        if (client != null)
            client.shutdown();
    }
}