Java tutorial
/** * Copyright (c) 2015, WSO2 Inc. (http://www.wso2.org) All Rights Reserved. * * WSO2 Inc. 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.wso2.carbon.inbound.endpoint.protocol.rabbitmq; import com.rabbitmq.client.Address; import com.rabbitmq.client.Channel; import com.rabbitmq.client.Connection; import com.rabbitmq.client.ConnectionFactory; import org.apache.axis2.context.MessageContext; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import java.io.IOException; import java.util.Hashtable; import java.util.concurrent.TimeoutException; public class RabbitMQUtils { private static final Log log = LogFactory.getLog(RabbitMQUtils.class); public static Connection createConnection(ConnectionFactory factory, Address[] addresses) throws IOException { Connection connection = null; try { connection = factory.newConnection(addresses); } catch (TimeoutException e) { log.error("Error while creating new connection", e); } return connection; } public static String getProperty(MessageContext mc, String key) { return (String) mc.getProperty(key); } public static boolean isDurableQueue(Hashtable<String, String> properties) { String durable = properties.get(RabbitMQConstants.QUEUE_DURABLE); return durable != null && Boolean.parseBoolean(durable); } public static boolean isExclusiveQueue(Hashtable<String, String> properties) { String exclusive = properties.get(RabbitMQConstants.QUEUE_EXCLUSIVE); return exclusive != null && Boolean.parseBoolean(exclusive); } public static boolean isAutoDeleteQueue(Hashtable<String, String> properties) { String autoDelete = properties.get(RabbitMQConstants.QUEUE_AUTO_DELETE); return autoDelete != null && Boolean.parseBoolean(autoDelete); } public static boolean isQueueAvailable(Connection connection, String queueName) throws IOException { Channel channel = connection.createChannel(); try { // check availability of the named queue // if an error is encountered, including if the queue does not exist and if the // queue is exclusively owned by another connection channel.queueDeclarePassive(queueName); return true; } catch (IOException e) { return false; } } /** * * @param connection * @param queueName * @param isDurable * @param isExclusive * @param isAutoDelete * @throws IOException */ public static void declareQueue(Connection connection, String queueName, boolean isDurable, boolean isExclusive, boolean isAutoDelete) throws IOException { boolean queueAvailable = isQueueAvailable(connection, queueName); Channel channel = connection.createChannel(); if (!queueAvailable) { if (log.isDebugEnabled()) { log.debug("Queue :" + queueName + " not found or already declared exclusive. Declaring the queue."); } // Declare the named queue if it does not exists. if (!channel.isOpen()) { channel = connection.createChannel(); log.debug("Channel is not open. Creating a new channel."); } try { channel.queueDeclare(queueName, isDurable, isExclusive, isAutoDelete, null); } catch (IOException e) { handleException("Error while creating queue: " + queueName, e); } } } public static void declareQueue(Connection connection, String queueName, Hashtable<String, String> properties) throws IOException { Boolean queueAvailable = isQueueAvailable(connection, queueName); Channel channel = connection.createChannel(); if (!queueAvailable) { // Declare the named queue if it does not exists. if (!channel.isOpen()) { channel = connection.createChannel(); log.debug("Channel is not open. Creating a new channel."); } try { channel.queueDeclare(queueName, isDurableQueue(properties), isExclusiveQueue(properties), isAutoDeleteQueue(properties), null); } catch (IOException e) { handleException("Error while creating queue: " + queueName, e); } } } public static void declareExchange(Connection connection, String exchangeName, Hashtable<String, String> properties) throws IOException { Boolean exchangeAvailable = false; Channel channel = connection.createChannel(); String exchangeType = properties.get(RabbitMQConstants.EXCHANGE_TYPE); String durable = properties.get(RabbitMQConstants.EXCHANGE_DURABLE); try { // check availability of the named exchange. // The server will raise an IOException // if the named exchange already exists. channel.exchangeDeclarePassive(exchangeName); exchangeAvailable = true; } catch (IOException e) { log.info("Exchange :" + exchangeName + " not found.Declaring exchange."); } if (!exchangeAvailable) { // Declare the named exchange if it does not exists. if (!channel.isOpen()) { channel = connection.createChannel(); log.debug("Channel is not open. Creating a new channel."); } try { if (exchangeType != null && !exchangeType.equals("")) { if (durable != null && !durable.equals("")) { channel.exchangeDeclare(exchangeName, exchangeType, Boolean.parseBoolean(durable)); } else { channel.exchangeDeclare(exchangeName, exchangeType, true); } } else { channel.exchangeDeclare(exchangeName, "direct", true); } } catch (IOException e) { handleException("Error occurred while declaring exchange.", e); } } try { channel.close(); } catch (TimeoutException e) { log.error("Error occurred while closing connection.", e); } } public static void handleException(String message, Exception e) { log.error(message, e); throw new RabbitMQException(message, e); } }