com.dateofrock.aws.simplesqs.JobConsumer.java Source code

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Here is the source code for com.dateofrock.aws.simplesqs.JobConsumer.java

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/*
 *   Copyright 2012 Takehito Tanabe (dateofrock at gmail dot com)
 *
 *   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.dateofrock.aws.simplesqs;

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

import com.amazonaws.services.sqs.AmazonSQS;
import com.amazonaws.services.sqs.model.DeleteMessageRequest;
import com.amazonaws.services.sqs.model.GetQueueUrlRequest;
import com.amazonaws.services.sqs.model.GetQueueUrlResult;
import com.amazonaws.services.sqs.model.Message;
import com.amazonaws.services.sqs.model.ReceiveMessageRequest;
import com.amazonaws.services.sqs.model.ReceiveMessageResult;
import com.dateofrock.simpledbmapper.SimpleDBMapper;
import com.dateofrock.simpledbmapper.SimpleDBMapperNotFoundException;

/**
 * 
 * @author Takehito Tanabe (dateofrock at gmail dot com)
 */
public class JobConsumer {

    protected Reflector reflector;
    protected SimpleDBMapper sdbMapper;
    protected AmazonSQS sqs;

    protected int maxNumberOfMessages = 1;

    public JobConsumer(SimpleDBMapper sdbMapper, AmazonSQS sqs) {
        this.reflector = new Reflector();
        this.sdbMapper = sdbMapper;
        this.sqs = sqs;
    }

    public void consume(Class<? extends AbstractJobTicket> clazz) {
        String queueName = this.reflector.findQueueName(clazz);
        GetQueueUrlResult result = this.sqs.getQueueUrl(new GetQueueUrlRequest(queueName));
        String queueUrl = result.getQueueUrl();

        ReceiveMessageResult receivedMessage = this.sqs.receiveMessage(
                new ReceiveMessageRequest(queueUrl).withMaxNumberOfMessages(this.maxNumberOfMessages));
        List<Message> messages = receivedMessage.getMessages();
        for (Message message : messages) {
            String jobId = message.getBody();
            String receiptHandle = message.getReceiptHandle();

            AbstractJobTicket jobTicket = null;
            try {
                jobTicket = this.sdbMapper.load(clazz, jobId);
                jobTicket.receiptHandle = receiptHandle;

            } catch (SimpleDBMapperNotFoundException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
                // FIXME Message??
                this.sqs.deleteMessage(new DeleteMessageRequest(queueUrl, receiptHandle));
                return;
            }

            Status currentStatus = Status.fromJobTicket(jobTicket);
            switch (currentStatus) {
            case WAITING:
                jobTicket.status = Status.IN_PROGRESS.getValue();
                jobTicket.updatedAt = new Date();
                this.sdbMapper.save(jobTicket);

                try {
                    // 
                    jobTicket.execute();
                } catch (Exception e) {
                    // StackTrace?
                    StringWriter writer = new StringWriter();
                    PrintWriter printWriter = new PrintWriter(writer);
                    e.printStackTrace(printWriter);
                    printWriter.flush();
                    printWriter.close();
                    try {
                        writer.close();
                    } catch (IOException ignore) {
                    }
                    jobTicket.exceptionStackTrace = writer.toString();
                    jobTicket.status = Status.FAILURE.getValue();
                    jobTicket.updatedAt = new Date();
                    this.sdbMapper.save(jobTicket);
                    break;
                }

                jobTicket.status = Status.SUCCESS.getValue();
                jobTicket.updatedAt = new Date();
                this.sdbMapper.save(jobTicket);
                break;
            case IN_PROGRESS:
                jobTicket.processIfInProgress();
                break;
            case SUCCESS:

                break;
            case FAILURE:

                break;
            default:
                break;
            }

        }
    }
}