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.AMQP; import com.rabbitmq.client.Channel; import com.rabbitmq.client.Connection; import com.rabbitmq.client.Envelope; import com.rabbitmq.client.QueueingConsumer; import org.apache.airavata.common.utils.AiravataUtils; import org.apache.airavata.common.utils.ServerSettings; import org.apache.airavata.common.utils.ThriftUtils; import org.apache.airavata.messaging.core.MessageContext; import org.apache.airavata.messaging.core.MessageHandler; import org.apache.airavata.model.messaging.event.ExperimentSubmitEvent; import org.apache.airavata.model.messaging.event.Message; import org.apache.airavata.model.messaging.event.MessageType; import org.apache.airavata.model.messaging.event.ProcessSubmitEvent; import org.apache.thrift.TBase; import org.apache.thrift.TException; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import java.io.IOException; public class ExperimentConsumer extends QueueingConsumer { private static final Logger log = LoggerFactory.getLogger(ExperimentConsumer.class); private MessageHandler handler; private Channel channel; private Connection connection; public ExperimentConsumer(MessageHandler messageHandler, Connection connection, Channel channel) { super(channel); this.handler = messageHandler; this.connection = connection; this.channel = channel; } @Override public void handleDelivery(String consumerTag, Envelope envelope, AMQP.BasicProperties properties, byte[] body) throws IOException { Message message = new Message(); try { ThriftUtils.createThriftFromBytes(body, message); long deliveryTag = envelope.getDeliveryTag(); if (message.getMessageType() == MessageType.EXPERIMENT || message.getMessageType() == MessageType.EXPERIMENT_CANCEL) { TBase event = null; String gatewayId = null; ExperimentSubmitEvent experimentEvent = new ExperimentSubmitEvent(); ThriftUtils.createThriftFromBytes(message.getEvent(), experimentEvent); log.info(" Message Received with message id '" + message.getMessageId() + "' and with message type '" + message.getMessageType() + "' for experimentId:" + " " + experimentEvent.getExperimentId()); event = experimentEvent; gatewayId = experimentEvent.getGatewayId(); MessageContext messageContext = new MessageContext(event, message.getMessageType(), message.getMessageId(), gatewayId, deliveryTag); messageContext.setUpdatedTime(AiravataUtils.getTime(message.getUpdatedTime())); messageContext.setIsRedeliver(envelope.isRedeliver()); handler.onMessage(messageContext); } else { log.error("{} message type is not handle in ProcessLaunch Subscriber. Sending ack for " + "delivery tag {} ", message.getMessageType().name(), deliveryTag); sendAck(deliveryTag); } } catch (TException e) { String msg = "Failed to de-serialize the thrift message, from routing keys:" + envelope.getRoutingKey(); log.warn(msg, e); } } private void sendAck(long deliveryTag) { try { if (channel.isOpen()) { channel.basicAck(deliveryTag, false); } else { channel = connection.createChannel(); channel.basicQos(ServerSettings.getRabbitmqPrefetchCount()); channel.basicAck(deliveryTag, false); } } catch (IOException e) { log.error(e.getMessage(), e); } } }