Java tutorial
/** * * 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. */ package org.apache.airavata.messaging.core.impl; import com.rabbitmq.client.Channel; import com.rabbitmq.client.Connection; import com.rabbitmq.client.ConnectionFactory; import com.rabbitmq.client.MessageProperties; import com.rabbitmq.client.ShutdownListener; import com.rabbitmq.client.ShutdownSignalException; import org.apache.airavata.common.exception.AiravataException; import org.apache.airavata.common.utils.ThriftUtils; import org.apache.airavata.messaging.core.MessageContext; import org.apache.airavata.messaging.core.Publisher; import org.apache.airavata.messaging.core.RabbitMQProperties; import org.apache.airavata.model.messaging.event.Message; import org.apache.thrift.TException; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import java.io.IOException; import java.util.function.Function; public class RabbitMQPublisher implements Publisher { private static final Logger log = LoggerFactory.getLogger(RabbitMQPublisher.class); private final RabbitMQProperties properties; private final Function<MessageContext, String> routingKeySupplier; private Connection connection; private Channel channel; public RabbitMQPublisher(RabbitMQProperties properties, Function<MessageContext, String> routingKeySupplier) throws AiravataException { this.properties = properties; this.routingKeySupplier = routingKeySupplier; connect(); } public RabbitMQPublisher(RabbitMQProperties properties) throws AiravataException { this.properties = properties; routingKeySupplier = null; connect(); } private void connect() throws AiravataException { try { ConnectionFactory connectionFactory = new ConnectionFactory(); connectionFactory.setUri(properties.getBrokerUrl()); connectionFactory.setAutomaticRecoveryEnabled(properties.isAutoRecoveryEnable()); connection = connectionFactory.newConnection(); connection.addShutdownListener(new ShutdownListener() { public void shutdownCompleted(ShutdownSignalException cause) { } }); log.info("connected to rabbitmq: " + connection + " for " + properties.getExchangeName()); channel = connection.createChannel(); if (properties.getPrefetchCount() > 0) { channel.basicQos(properties.getPrefetchCount()); } if (properties.getExchangeName() != null) { channel.exchangeDeclare(properties.getExchangeName(), properties.getExchangeType(), true); //durable } } catch (Exception e) { String msg = "RabbitMQ connection issue for exchange : " + properties.getExchangeName(); log.error(msg); throw new AiravataException(msg, e); } } @Override public void publish(MessageContext messageContext) throws AiravataException { try { byte[] body = ThriftUtils.serializeThriftObject(messageContext.getEvent()); Message message = new Message(); message.setEvent(body); message.setMessageId(messageContext.getMessageId()); message.setMessageType(messageContext.getType()); message.setUpdatedTime(messageContext.getUpdatedTime().getTime()); String routingKey = routingKeySupplier.apply(messageContext); // log.info("publish messageId:" + messageContext.getMessageId() + ", messageType:" + messageContext.getType() + ", to routingKey:" + routingKey); byte[] messageBody = ThriftUtils.serializeThriftObject(message); send(messageBody, routingKey); } catch (TException e) { String msg = "Error while deserializing the object"; log.error(msg, e); throw new AiravataException(msg, e); } catch (Exception e) { String msg = "Error while sending to rabbitmq"; log.error(msg, e); throw new AiravataException(msg, e); } } /** * This method is used only for publishing DB Events * @param messageContext object of message context which will include actual db event and other information * @param routingKey * @throws AiravataException */ @Override public void publish(MessageContext messageContext, String routingKey) throws AiravataException { try { byte[] body = ThriftUtils.serializeThriftObject(messageContext.getEvent()); Message message = new Message(); message.setEvent(body); message.setMessageId(messageContext.getMessageId()); message.setMessageType(messageContext.getType()); if (messageContext.getUpdatedTime() != null) { message.setUpdatedTime(messageContext.getUpdatedTime().getTime()); } // log.info("publish messageId:" + messageContext.getMessageId() + ", messageType:" + messageContext.getType() + ", to routingKey:" + routingKey); byte[] messageBody = ThriftUtils.serializeThriftObject(message); send(messageBody, routingKey); } catch (TException e) { String msg = "Error while deserializing the object"; log.error(msg, e); throw new AiravataException(msg, e); } catch (Exception e) { String msg = "Error while sending to rabbitmq"; log.error(msg, e); throw new AiravataException(msg, e); } } public void send(byte[] message, String routingKey) throws Exception { try { channel.basicPublish(properties.getExchangeName(), routingKey, MessageProperties.PERSISTENT_TEXT_PLAIN, message); } catch (IOException e) { String msg = "Failed to publish message to exchange: " + properties.getExchangeName(); log.error(msg, e); throw new Exception(msg, e); } } }