Java tutorial
/******************************************************************************* * ESO - European Southern Observatory * * (c) European Southern Observatory, 2011 * Copyright by ESO * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this library; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA * * "@(#) $Id$" * * who when what * ---------------- ---------- ---------------------------------------------- * COMODO - Created. * */ package Monitor; import java.io.IOException; import java.util.Properties; import com.rabbitmq.client.ConnectionFactory; import com.rabbitmq.client.Connection; import com.rabbitmq.client.Channel; import com.rabbitmq.client.QueueingConsumer; import org.apache.log4j.Logger; import org.apache.log4j.PropertyConfigurator; import org.apache.commons.scxml.model.ModelException; import org.apache.commons.scxml.TriggerEvent; import Monitor.SMJavaInvoker; import RMQCommons.SMEngine; import RMQCommons.Message; /** * * @author COMODO * @version $Id$ */ public abstract class MonitorImplAbstract { private final static String CMD_QUEUE_NAME = "MONITORIMPL_CMD"; // for point to point commands private final static String DATA_EXCHANGE_NAME = "DATA"; // for data pub/sub private final static String CMD_EXCHANGE_NAME = "CMD"; // for broadcasted commands private Logger mLogger = null; private SMEngine mEngine = null; private ConnectionFactory mFactory = null; private Connection mConnection = null; private Channel mChannel = null; private QueueingConsumer mConsumer = null; private boolean mIsRunning = false; public MonitorImplAbstract() { mLogger = Logger.getLogger("Monitor"); PropertyConfigurator.configure("log4j.properties"); try { mFactory = new ConnectionFactory(); mFactory.setHost("localhost"); mConnection = mFactory.newConnection(); mChannel = mConnection.createChannel(); /* * Defines that messages in this queue are persistent (i.e. to be saved on disk) * so that even if RabbitMQ server quits the messages is not lost. * Note that when publishing a message, the msg itself has to be declared persistent. */ boolean durable = false; // for commands we don't want it! /* * true if the server should consider messages acknowledged once delivered; * false if the server should expect explicit acknowledgements. */ boolean autoAck = true; // command queue boolean exclusive = false; // restricted to this connection boolean autoDelete = false; // server will delete the queue when no longer in use mChannel.queueDeclare(CMD_QUEUE_NAME, durable, exclusive, autoDelete, null); // broadcasted commands (don't need to subscribe to a topic) mChannel.exchangeDeclare(CMD_EXCHANGE_NAME, "fanout", durable); String cmdFanoutQueueName = mChannel.queueDeclare().getQueue(); mChannel.queueBind(cmdFanoutQueueName, CMD_EXCHANGE_NAME, ""); // data topics to subscribe durable = true; // for data we want persistance! mChannel.exchangeDeclare(DATA_EXCHANGE_NAME, "topic", durable); String dataPubsubQueueName = mChannel.queueDeclare().getQueue(); mChannel.queueBind(dataPubsubQueueName, DATA_EXCHANGE_NAME, "EncoderHealthSV"); mChannel.queueBind(dataPubsubQueueName, DATA_EXCHANGE_NAME, "MotorHealthSV"); mChannel.queueBind(dataPubsubQueueName, DATA_EXCHANGE_NAME, "NamedPositionSV"); mChannel.queueBind(dataPubsubQueueName, DATA_EXCHANGE_NAME, "Goal"); // define which queues to get the messages from mConsumer = new QueueingConsumer(mChannel); mChannel.basicConsume(CMD_QUEUE_NAME, autoAck, mConsumer); mChannel.basicConsume(cmdFanoutQueueName, autoAck, mConsumer); mChannel.basicConsume(dataPubsubQueueName, autoAck, mConsumer); } catch (IOException e) { mLogger.error("Could not create RMQ channel: " + e.getMessage()); return; } try { mEngine = new SMEngine(mLogger, SMJavaInvoker.class); // The context has to be created before the actions/activities are executed mEngine.setContextVar("CHANNEL", mChannel); mEngine.setContextVar("CMD_QUEUE_NAME", CMD_QUEUE_NAME); mEngine.setContextVar("CMD_EXCHANGE_NAME", CMD_EXCHANGE_NAME); mEngine.setContextVar("DATA_EXCHANGE_NAME", DATA_EXCHANGE_NAME); mEngine.loadModel("Monitor.xml"); mEngine.startExecution(); } catch (IOException e) { mLogger.error("Could not start SM execution: " + e.getMessage()); return; } mIsRunning = true; } public Logger getLogger() { return mLogger; } public String getCmdQueueName() { return CMD_QUEUE_NAME; } public Channel getChannel() { return mChannel; } public QueueingConsumer getConsumer() { return mConsumer; } public boolean isRunning() { return mIsRunning; } public void closeConnections() { try { mChannel.close(); mConnection.close(); } catch (IOException e) { mLogger.error("Could not close RMQ connection: " + e.getMessage()); } } /** * Resets the StateMachine to initial state */ public void smReset() { try { mEngine.getEngine().reset(); mLogger.info("Reset State Machine"); } catch (ModelException e) { mLogger.error("Could not reset the enigne: " + e.getMessage()); } } /** * Loads a SCXML definition file. * If given an empty string for file, it reloads the currently active file, * otherwise it loads the file from the given path. * @return true on success; false on error e.g. "file not found" */ public boolean smLoadDefinition(final String fileName) { String modelLoc = fileName; if (fileName.isEmpty()) { modelLoc = "Monitor.xml"; } try { mEngine.loadModel(modelLoc); mEngine.startExecution(); mLogger.info("Reloaded model: " + modelLoc); } catch (IOException e) { mLogger.error("Could not reload the model: " + modelLoc + "(" + e.getMessage() + ")"); } return true; } /** * Retrieve current state as string. */ public String smGetCurrentState() { return mEngine.getCurrentState(); } public void smFireSignal(Message msg) { String signal = msg.getName(); String[] params = msg.getParams(); // update the SM context with the parameters of the message // which can be used in guards expressions msg.updateContext(mEngine); // save in the SM context as last message so that actions can retrieve // the parameters ==> Probably obsolete due to msg.updateContext mEngine.setContextVar("LASTMSG", msg); mLogger.debug("Signal: " + signal); for (int i = 0; i < params.length; i++) { mLogger.debug(" Param[" + i + "] = " + params[i]); } /* * Maintenance signals for state machine */ if (signal.toUpperCase().matches("SMSTATUS") || signal.toUpperCase().matches("SMSTATE")) { mLogger.info("State: " + smGetCurrentState()); return; } else if (signal.toUpperCase().matches("SMRESET")) { smReset(); return; } else if (signal.toUpperCase().matches("SMRELOAD")) { smLoadDefinition(""); return; } else if (signal.toUpperCase().matches("SMEXIT")) { mIsRunning = false; // force to quit return; } else if (signal.toUpperCase().matches("SMLOG")) { if (params.length == 2) { String property = params[0]; String value = params[1]; mLogger.info("smLog " + property + " " + value); Properties logProperties = new Properties(); logProperties.put(property, value); PropertyConfigurator.configure(logProperties); } } TriggerEvent evnt = new TriggerEvent(signal, TriggerEvent.SIGNAL_EVENT, null); try { mEngine.getEngine().triggerEvent(evnt); } catch (ModelException e) { mLogger.error("Propagating event to the SM engine: " + e.getMessage()); } /* * If final state is reached, the application can quit! */ mIsRunning = (mEngine.getEngine().getCurrentStatus().isFinal() == false); } }