synchronously receives message from JMS queue server - Java Message

Java examples for Message:JMS

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Description

synchronously receives message from JMS queue server

Demo Code

package com.dreamlabs.activemq;

/*/*from   w w  w .  j  a v  a2  s .  c  o m*/
 *  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.
 */
import java.util.Random;

import javax.jms.Connection;
import javax.jms.Destination;
import javax.jms.JMSException;
import javax.jms.MapMessage;
import javax.jms.Message;
import javax.jms.MessageConsumer;
import javax.jms.MessageProducer;
import javax.jms.Session;

import org.apache.activemq.ActiveMQConnectionFactory;

/**
 * The Supplier synchronously receives the order from the Vendor and
 * randomly responds with either the number ordered, or some lower
 * quantity. 
 */
public class Supplier implements Runnable {
  private String url;
  private String user;
  private String password;
  private final String ITEM;
  private final String QUEUE;
  
  public Supplier(String item, String queue, String url, String user, String password) {
    this.url = url;
    this.user = user;
    this.password = password;
    this.ITEM = item;
    this.QUEUE = queue;
  }
  
  public void run() {
    ActiveMQConnectionFactory connectionFactory = new ActiveMQConnectionFactory(user, password, url);
    Session session = null;
    Destination orderQueue;
    try {
      Connection connection = connectionFactory.createConnection();

      session = connection.createSession(true, Session.SESSION_TRANSACTED);
      orderQueue = session.createQueue(QUEUE);
      MessageConsumer consumer = session.createConsumer(orderQueue);
      
      connection.start();
      
      while (true) {
        Message message = consumer.receive();
        MessageProducer producer = session.createProducer(message.getJMSReplyTo());
        MapMessage orderMessage;
        if (message instanceof MapMessage) {
          orderMessage = (MapMessage) message;
        } else {
          // End of Stream
          producer.send(session.createMessage());
          session.commit();
          producer.close();
          break;
        }
        
        int quantity = orderMessage.getInt("Quantity");
        System.out.println(ITEM + " Supplier: Vendor ordered " + quantity + " " + orderMessage.getString("Item"));
        
        MapMessage outMessage = session.createMapMessage();
        outMessage.setInt("VendorOrderNumber", orderMessage.getInt("VendorOrderNumber"));
        outMessage.setString("Item", ITEM);
        
        quantity = Math.min(
            orderMessage.getInt("Quantity"),
            new Random().nextInt(orderMessage.getInt("Quantity") * 10));
        outMessage.setInt("Quantity", quantity);
        
        producer.send(outMessage);
        System.out.println(ITEM + " Supplier: Sent " + quantity + " " + ITEM + "(s)");
        session.commit();
        System.out.println(ITEM + " Supplier: committed transaction");
        producer.close();
      }
      connection.close();
    } catch (JMSException e) {
      e.printStackTrace();
    }
  }
  
  public static void main(String[] args) {
    String url = "tcp://localhost:61616";
    String user = null;
    String password = null;
    String item = "HardDrive";
    
    if (args.length >= 1) {
      item = args[0];
    }
    String queue;
    if ("HardDrive".equals(item)) {
      queue = "StorageOrderQueue";
    } else if ("Monitor".equals(item)) {
      queue = "MonitorOrderQueue";
    } else {
      throw new IllegalArgumentException("Item must be either HardDrive or Monitor");
    }
    
    if (args.length >= 2) {
      url = args[1];
    }
    
    if (args.length >= 3) {
      user = args[2];
    }

    if (args.length >= 4) {
      password = args[3];
    }
    
    Supplier s = new Supplier(item, queue, url, user, password);
    
    new Thread(s, "Supplier " + item).start();
  }
}

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