Java tutorial
/* * ************************************************************************************* * Copyright (C) 2006-2015 EsperTech, Inc. All rights reserved. * * http://www.espertech.com/esper * * http://www.espertech.com * * ---------------------------------------------------------------------------------- * * The software in this package is published under the terms of the GPL license * * a copy of which has been included with this distribution in the license.txt file. * * ************************************************************************************* */ package com.espertech.esperio.amqp; import com.espertech.esper.client.EPException; import com.espertech.esper.dataflow.annotations.DataFlowContext; import com.espertech.esper.dataflow.annotations.DataFlowOpPropertyHolder; import com.espertech.esper.dataflow.interfaces.*; import com.rabbitmq.client.*; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import java.io.IOException; public class AMQPSource implements DataFlowSourceOperator { private static final Log log = LogFactory.getLog(AMQPSource.class); @DataFlowOpPropertyHolder private AMQPSettingsSource settings; private transient Connection connection; private transient Channel channel; private transient QueueingConsumer consumer; private transient String consumerTag; @DataFlowContext protected EPDataFlowEmitter graphContext; private ThreadLocal<AMQPToObjectCollectorContext> collectorDataTL = new ThreadLocal<AMQPToObjectCollectorContext>() { protected synchronized AMQPToObjectCollectorContext initialValue() { return null; } }; public AMQPSource() { } public DataFlowOpInitializeResult initialize(DataFlowOpInitializateContext context) throws Exception { return null; } public void open(DataFlowOpOpenContext openContext) { log.info("Opening AMQP, settings are: " + settings.toString()); try { final ConnectionFactory connectionFactory = new ConnectionFactory(); connectionFactory.setHost(settings.getHost()); if (settings.getPort() > -1) { connectionFactory.setPort(settings.getPort()); } if (settings.getUsername() != null) { connectionFactory.setUsername(settings.getUsername()); } if (settings.getPassword() != null) { connectionFactory.setPassword(settings.getPassword()); } if (settings.getVhost() != null) { connectionFactory.setVirtualHost(settings.getVhost()); } connection = connectionFactory.newConnection(); channel = connection.createChannel(); channel.basicQos(settings.getPrefetchCount()); if (settings.getExchange() != null) { channel.exchangeDeclarePassive(settings.getExchange()); } final AMQP.Queue.DeclareOk queue; if (settings.getQueueName() == null || settings.getQueueName().trim().length() == 0) { queue = channel.queueDeclare(); } else { // java.lang.String queue,boolean durable,boolean exclusive,boolean autoDelete,java.util.Map<java.lang.String,java.lang.Object> arguments) throws java.io.IOException queue = channel.queueDeclare(settings.getQueueName(), settings.isDeclareDurable(), settings.isDeclareExclusive(), settings.isDeclareAutoDelete(), settings.getDeclareAdditionalArgs()); } if (settings.getExchange() != null && settings.getRoutingKey() != null) { channel.queueBind(queue.getQueue(), settings.getExchange(), settings.getRoutingKey()); } final String queueName = queue.getQueue(); log.info("AMQP consuming queue " + queueName + (settings.isLogMessages() ? " with logging" : "")); consumer = new QueueingConsumer(channel); consumerTag = channel.basicConsume(queueName, settings.isConsumeAutoAck(), consumer); } catch (IOException e) { String message = "AMQP source setup failed: " + e.getMessage(); log.error(message, e); throw new EPException(message, e); } } public void next() throws InterruptedException { if (consumer == null) { log.warn("Consumer not started"); } else { final QueueingConsumer.Delivery msg = consumer.nextDelivery(settings.getWaitMSecNextMsg()); if (msg == null) { if (settings.isLogMessages() && log.isDebugEnabled()) { log.debug("No message received"); } return; } final byte[] bytes = msg.getBody(); if (settings.isLogMessages() && log.isDebugEnabled()) { log.debug("Received " + bytes.length + " bytes, to be processed by " + settings.getCollector()); } AMQPToObjectCollectorContext holder = collectorDataTL.get(); if (holder == null) { holder = new AMQPToObjectCollectorContext(graphContext, bytes, msg); collectorDataTL.set(holder); } else { holder.setBytes(bytes); holder.setDelivery(msg); } settings.getCollector().collect(holder); } } public void close(DataFlowOpCloseContext openContext) { try { if (channel != null) { if (consumerTag != null) { channel.basicCancel(consumerTag); } channel.close(); } } catch (IOException e) { log.warn("Error closing AMQP channel", e); } try { if (connection != null) { connection.close(); } } catch (IOException e) { log.warn("Error closing AMQP connection", e); } } }