Java tutorial
//********************************************************************** // cresendo - teC REceive SEND // // Copyright (C) 2008,2009 Mark Matthews // Distributed under the terms of the GNU General Public License // // This file is part of Cresendo. // Cresendo is free software: you can redistribute it and/or modify // it under the terms of the GNU General Public License as published by // the Free Software Foundation, either version 3 of the License, or // (at your option) any later version. // // Cresendo 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 General Public License for more details. // // You should have received a copy of the GNU General Public License // along with Cresendo. If not, see <http://www.gnu.org/licenses/>. //*********************************************************************** import java.io.File; import java.io.Reader; import java.io.FileReader; import java.io.FileNotFoundException; import java.io.IOException; import java.lang.String; import java.lang.Class; import java.lang.reflect.Constructor; import java.lang.reflect.InvocationTargetException; import java.util.Enumeration; import java.util.Iterator; import java.util.List; import java.util.Vector; import org.apache.commons.cli.Option; import org.apache.commons.cli.Options; import org.apache.commons.cli.BasicParser; import org.apache.commons.cli.HelpFormatter; import org.apache.commons.cli.CommandLine; import org.apache.commons.cli.UnrecognizedOptionException; import org.apache.commons.cli.MissingOptionException; import org.apache.commons.cli.MissingArgumentException; import org.apache.commons.cli.ParseException; import org.apache.commons.configuration.XMLConfiguration; import org.apache.commons.configuration.HierarchicalConfiguration; import org.apache.commons.configuration.ConfigurationException; import org.apache.commons.configuration.tree.ConfigurationNode; import com.tivoli.tec.event_delivery.TECAgent; import com.tivoli.tec.event_delivery.EDException; import com.ibm.logging.FileHandler; import com.ibm.logging.MessageLogger; import com.ibm.logging.TraceLogger; import com.ibm.logging.LogRecord; public class Cresendo { public static String instanceName = "default"; // Cresendo instance name public static String configDir = null; // Path to configuration directory public static String logDir = null; // Path to log directory public static String dirSep = null; // Platform directory separator public static String logPath = null; // Path to message file log public static String tracePath = null; // Path to trace file log public static String statusPath = null; // Path to status file log public static FileHandler msgHandler = null; // Message file handler object public static FileHandler trcHandler = null; // Trace file handler object public static MessageLogger msgLogger = null; // Message logging object public static TraceLogger trcLogger = null; // Trace logging object public static StatusLogger statLogger = null; // Status logging object private static void checkConfigFile(String cfgFile) { File f = new File(cfgFile); if (!f.exists()) { System.err.println("Error: File does not exist: " + cfgFile); System.exit(1); } if (!f.canRead()) { System.err.println("Error: Unable to read file: " + cfgFile); System.exit(1); } } public static void main(String[] args) { String cfgFileReceiver = null; // Path to config file for eif receiver agent String cfgFileEngine = null; // Path to config file for xml event engine Options opts = null; // Command line options HelpFormatter hf = null; // Command line help formatter // Setup the message record which will contain text written to the log file // // The message logger object is created when the "-l" is processed // as this object need to be associated with a log file // LogRecord msg = new LogRecord(LogRecord.TYPE_INFO, "Cresendo", "main", "", "", "", "", ""); // Get the directory separator (defaults to "/") // dirSep = System.getProperty("file.separator", "/"); // Initialise the structure containing the event handler objects // Vector<IEventHandler> eventHandler = new Vector<IEventHandler>(10, 10); // Process the command line arguments // try { opts = new Options(); hf = new HelpFormatter(); opts.addOption("h", "help", false, "Command line arguments help"); opts.addOption("i", "instance name", true, "Name of cresendo instance"); opts.addOption("l", "log dir", true, "Path to log file directory"); opts.addOption("c", "config dir", true, "Path to configuarion file directory"); opts.getOption("l").setRequired(true); opts.getOption("c").setRequired(true); BasicParser parser = new BasicParser(); CommandLine cl = parser.parse(opts, args); // Print out some help and exit // if (cl.hasOption('h')) { hf.printHelp("Options", opts); System.exit(0); } // Set the instance name // if (cl.hasOption('i')) { instanceName = cl.getOptionValue('i'); // Set to something other than "default" } // Setup the message and trace logging objects for the EventEngine // if (cl.hasOption('l')) { // Setup the the paths to the message, trace and status log files // logDir = cl.getOptionValue("l"); logPath = logDir + dirSep + instanceName + "-engine.log"; tracePath = logDir + dirSep + instanceName + "-engine.trace"; statusPath = logDir + dirSep + instanceName + "-engine.status"; } else { // NOTE: This should be picked up by the MissingOptionException catch below // but I couldn't get this to work so I added the following code: // hf.printHelp("Option 'l' is a required option", opts); System.exit(1); } // Read the receiver and engine config files in the config directory // if (cl.hasOption('c')) { // Setup and check path to eif config file for TECAgent receiver object // configDir = cl.getOptionValue("c"); cfgFileReceiver = configDir + dirSep + instanceName + ".conf"; checkConfigFile(cfgFileReceiver); // Setup and check path to xml config file for the EventEngine // cfgFileEngine = cl.getOptionValue("c") + dirSep + instanceName + ".xml"; checkConfigFile(cfgFileEngine); } else { // NOTE: This should be picked up by the MissingOptionException catch below // but I couldn't get this to work so I added the following code: // hf.printHelp("Option 'c' is a required option", opts); System.exit(1); } } catch (UnrecognizedOptionException e) { hf.printHelp(e.toString(), opts); System.exit(1); } catch (MissingOptionException e) { hf.printHelp(e.toString(), opts); System.exit(1); } catch (MissingArgumentException e) { hf.printHelp(e.toString(), opts); System.exit(1); } catch (ParseException e) { e.printStackTrace(); System.exit(1); } catch (Exception e) { System.err.println(e.toString()); System.exit(1); } // Main program // try { // ===================================================================== // Setup the message, trace and status logger objects // try { msgHandler = new FileHandler("cresendo", "message handler", logPath); msgHandler.openDevice(); msgLogger = new MessageLogger("cresendo", "message log"); msgLogger.addHandler(msgHandler); trcHandler = new FileHandler("cresendo", "trace handler", tracePath); trcHandler.openDevice(); trcLogger = new TraceLogger("cresendo", "trace log"); trcLogger.addHandler(trcHandler); statLogger = new StatusLogger(statusPath); } catch (Exception e) { System.err.println(e.toString()); System.exit(1); } // Add the shutdown hook // Runtime.getRuntime().addShutdownHook(new ShutdownThread(msgLogger, instanceName)); // --------------------------------------------------------------------- // ===================================================================== // Load and parse the xml event engine configuration file // // msg.setText("Loading xml engine from: '" + cfgFileEngine + "'"); try { XMLConfiguration xmlProcessor = new XMLConfiguration(); xmlProcessor.setFileName(cfgFileEngine); // Validate the xml against a document type declaration // xmlProcessor.setValidating(true); // Don't interpolate the tag contents by splitting them on a delimiter // (ie by default a comma) // xmlProcessor.setDelimiterParsingDisabled(true); // This will throw a ConfigurationException if the xml document does not // conform to its dtd. By doing this we hopefully catch any errors left // behind after the xml configuration file has been edited. // xmlProcessor.load(); // Setup the trace flag // ConfigurationNode engine = xmlProcessor.getRootNode(); List rootAttribute = engine.getAttributes(); for (Iterator it = rootAttribute.iterator(); it.hasNext();) { ConfigurationNode attr = (ConfigurationNode) it.next(); String attrName = attr.getName(); String attrValue = (String) attr.getValue(); if (attrValue == null || attrValue == "") { System.err.println("\n Error: The value of the attribute '" + attrName + "'" + "\n in the xml file '" + cfgFileEngine + "'" + "\n is not set"); System.exit(1); } if (attrName.matches("trace")) { if (attrValue.matches("true") || attrValue.matches("on")) { trcLogger.setLogging(true); } } if (attrName.matches("status")) { if (attrValue.matches("true") || attrValue.matches("on")) { statLogger.setLogging(true); } else { statLogger.setLogging(false); } } if (attrName.matches("interval")) { if (!attrValue.matches("[0-9]+")) { System.err.println("\n Error: The value of the interval attribute in: '" + cfgFileEngine + "'" + "\n should only contain digits from 0 to 9." + "\n It currently contains: '" + attrValue + "'"); System.exit(1); } statLogger.setInterval(Integer.parseInt(attrValue)); } } // Now build and instantiate the list of classes that will process events // received by the TECAgent receiver in a chain like manner. // List classes = xmlProcessor.configurationsAt("class"); for (Iterator it = classes.iterator(); it.hasNext();) { HierarchicalConfiguration sub = (HierarchicalConfiguration) it.next(); // sub contains now all data contained in a single <class></class> tag set // String className = sub.getString("name"); // Log message // msg.setText(msg.getText() + "\n Instantiated event handler class: '" + className + "'"); // The angle brackets describing the class of object held by the // Vector are implemented by Java 1.5 and have 2 effects. // // 1. The list accepts only elements of that class and nothing else // (Of course thanks to Auto-Wrap you can also add double-values) // // 2. the get(), firstElement() ... Methods don't return a Object, but // they deliver an element of the class. // Vector<Class> optTypes = new Vector<Class>(10, 10); Vector<Object> optValues = new Vector<Object>(10, 10); for (int i = 0; i <= sub.getMaxIndex("option"); i++) { Object optValue = null; String optVarName = sub.getString("option(" + i + ")[@varname]"); String optJavaType = sub.getString("option(" + i + ")[@javatype]"); // Use the specified java type in order to make the method call // to the heirarchical sub object [painful :-((] // if (optJavaType.matches("byte")) { optTypes.addElement(byte.class); optValue = sub.getByte("option(" + i + ")"); if (optValue == null) // Catch nulls { optValue = 0; // Set to something nullish } } else if (optJavaType.matches("short")) { optTypes.addElement(byte.class); optValue = sub.getShort("option(" + i + ")"); if (optValue == null) // Catch nulls { optValue = 0; // Set to something nullish } } else if (optJavaType.matches("int")) { optTypes.addElement(int.class); optValue = sub.getInt("option(" + i + ")"); if (optValue == null) // Catch nulls { optValue = 0; // Set to something nullish } } else if (optJavaType.matches("long")) { optTypes.addElement(long.class); optValue = sub.getLong("option(" + i + ")"); if (optValue == null) // Catch nulls { optValue = 0; // Set to something nullish } } else if (optJavaType.matches("float")) { optTypes.addElement(float.class); optValue = sub.getFloat("option(" + i + ")"); if (optValue == null) // Catch nulls { optValue = 0.0; // Set to something nullish } } else if (optJavaType.matches("double")) { optTypes.addElement(double.class); optValue = sub.getDouble("option(" + i + ")"); if (optValue == null) // Catch nulls { optValue = 0.0; // Set to something nullish } } else if (optJavaType.matches("boolean")) { optTypes.addElement(boolean.class); optValue = sub.getBoolean("option(" + i + ")"); if (optValue == null) // Catch nulls { optValue = false; // Set to something nullish } } else if (optJavaType.matches("String")) { optTypes.addElement(String.class); optValue = sub.getString("option(" + i + ")"); if (optValue == null) // Catch nulls { optValue = ""; // Set it to something nullish } } else { System.err.println( "Error: Unsupported java type found in xml config: '" + optJavaType + "'"); System.exit(1); } // Add option value element // // System.out.println("Option value is: '" + optValue.toString() + "'\n"); // optValues.addElement(optValue); // Append to message text // String msgTemp = msg.getText(); msgTemp += "\n option name: '" + optVarName + "'"; msgTemp += "\n option type: '" + optJavaType + "'"; msgTemp += "\n option value: '" + optValues.lastElement().toString() + "'"; msg.setText(msgTemp); } try { // Instantiate the class with the java reflection api // Class klass = Class.forName(className); // Setup an array of paramater types in order to retrieve the matching constructor // Class[] types = optTypes.toArray(new Class[optTypes.size()]); // Get the constructor for the class which matches the parameter types // Constructor konstruct = klass.getConstructor(types); // Create an instance of the event handler // IEventHandler eventProcessor = (IEventHandler) konstruct.newInstance(optValues.toArray()); // Add the instance to the list of event handlers // eventHandler.addElement(eventProcessor); } catch (InvocationTargetException e) { System.err.println("Error: " + e.toString()); System.exit(1); } catch (ClassNotFoundException e) { System.err.println("Error: class name not found: '" + className + "' \n" + e.toString()); System.exit(1); } catch (Exception e) { System.err.println( "Error: failed to instantiate class: '" + className + "' \n" + e.toString()); System.exit(1); } } } catch (ConfigurationException cex) // Something went wrong loading the xml file { System.err.println("\n" + "Error loading XML file: " + cfgFileEngine + "\n" + cex.toString()); System.exit(1); } catch (Exception e) { System.err.println(e.toString()); System.exit(1); } // --------------------------------------------------------------------- // ===================================================================== // Setup the TECAgent receiver // Reader cfgIn = null; try { cfgIn = new FileReader(cfgFileReceiver); } catch (Exception e) { System.err.println(e.toString()); System.exit(1); } // Start the TECAgent receiver and register the event engine handler // TECAgent receiver = new TECAgent(cfgIn, TECAgent.RECEIVER_MODE, false); EventEngine ee = new EventEngine(eventHandler, msgLogger, trcLogger); receiver.registerListener(ee); // Construct message and send it to the message log // String text = "\n Cresendo instance '" + instanceName + "' listening for events on port '" + receiver.getConfigVal("ServerPort") + "'"; msg.setText(msg.getText() + text); msgLogger.log(msg); // Send message to log // --------------------------------------------------------------------- // ===================================================================== // Initiate status logging // if (statLogger.isLogging()) { int seconds = statLogger.getInterval(); while (true) { try { statLogger.log(); } catch (Exception ex) { System.err.println("\n An error occurred while writing to '" + statusPath + "'" + "\n '" + ex.toString() + "'"); } Thread.sleep(seconds * 1000); // Convert sleep time to milliseconds } } // --------------------------------------------------------------------- } catch (Exception e) { System.err.println(e.toString()); System.exit(1); } } }