Java tutorial
/* * #%L * Wisdom-Framework * %% * Copyright (C) 2013 - 2014 Wisdom Framework * %% * Licensed 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. * #L% */ package org.wisdom.maven.utils; import com.google.common.base.Strings; import org.apache.commons.exec.*; import org.apache.commons.io.FileUtils; import org.apache.maven.plugin.MojoExecutionException; import org.wisdom.maven.mojos.AbstractWisdomMojo; import java.io.File; import java.io.IOException; import java.util.Enumeration; import java.util.Properties; /** * Launch the Wisdom Framework. * This class starts the Wisdom Framework. It handles background (start and stop) and foreground executions. */ public class WisdomExecutor { /** * Retrieves the version of Chameleon we use. */ public static final String CHAMELEON_VERSION = BuildConstants.get("CHAMELEON_VERSION"); /** * The maximum time to wait in ms for file creation and deletion. */ public static final int FILE_WAIT_TIMEOUT = 10000; /** * Launches the Wisdom server in background using the {@literal chameleon.sh} scripts. * This method works only on Linux and Mac OS X. * * @param mojo the mojo * @throws MojoExecutionException if the Wisdom instance cannot be started. */ public void executeInBackground(AbstractWisdomMojo mojo) throws MojoExecutionException { File script = new File(mojo.getWisdomRootDirectory(), "chameleon.sh"); if (!script.isFile()) { throw new MojoExecutionException("The 'chameleon.sh' file does not exist in " + mojo.getWisdomRootDirectory().getAbsolutePath() + " - cannot launch Wisdom"); } // Remove the RUNNING_PID file if exists. File pid = new File(mojo.getWisdomRootDirectory(), "RUNNING_PID"); if (pid.isFile()) { mojo.getLog().info("The RUNNING_PID file is present, deleting it"); FileUtils.deleteQuietly(pid); } // We create a command line, as we are using th toString method on it. CommandLine cmdLine = new CommandLine(script); appendSystemPropertiesToCommandLine(mojo, cmdLine); try { mojo.getLog().info("Launching Wisdom Server using '" + cmdLine.toString() + "'."); // As we know which command line we are executing, we can safely execute the command. Runtime.getRuntime().exec(cmdLine.toStrings(), null, mojo.getWisdomRootDirectory()); //NOSONAR see comment } catch (IOException e) { throw new MojoExecutionException("Cannot execute Wisdom", e); } } /** * Launches the Wisdom server. This method blocks until the wisdom server shuts down. * It uses the {@literal Java} executable directly. * * @param mojo the mojo * @param interactive enables the shell prompt * @param debug the debug port (0 to disable it) * @param jvmArgs JVM arguments to add to the `java` command (before the -jar argument). * @param destroyer a process destroyer that can be used to destroy the process, if {@code null} * a {@link org.apache.commons.exec.ShutdownHookProcessDestroyer} is used. * @throws MojoExecutionException if the Wisdom instance cannot be started or has thrown an unexpected status * while being stopped. */ public void execute(AbstractWisdomMojo mojo, boolean interactive, int debug, String jvmArgs, ProcessDestroyer destroyer) throws MojoExecutionException { // Get java File java = ExecUtils.find("java", new File(mojo.javaHome, "bin")); if (java == null) { throw new MojoExecutionException("Cannot find the java executable"); } CommandLine cmdLine = new CommandLine(java); if (debug != 0) { cmdLine.addArgument("-agentlib:jdwp=transport=dt_socket,server=y,suspend=n,address=" + debug, false); } if (!Strings.isNullOrEmpty(jvmArgs)) { cmdLine.addArguments(jvmArgs, false); } cmdLine.addArgument("-jar"); cmdLine.addArgument("bin/chameleon-core-" + CHAMELEON_VERSION + ".jar"); if (interactive) { cmdLine.addArgument("--interactive"); } appendSystemPropertiesToCommandLine(mojo, cmdLine); DefaultExecutor executor = new DefaultExecutor(); if (destroyer != null) { executor.setProcessDestroyer(destroyer); } else { executor.setProcessDestroyer(new ShutdownHookProcessDestroyer()); } executor.setWorkingDirectory(mojo.getWisdomRootDirectory()); if (interactive) { executor.setStreamHandler(new PumpStreamHandler(System.out, System.err, System.in)); //NOSONAR // Using the interactive mode the framework should be stopped using the 'exit' command, // and produce a '0' status. executor.setExitValue(0); } else { executor.setStreamHandler(new PumpStreamHandler(System.out, System.err)); // NOSONAR // As the execution is intended to be interrupted using CTRL+C, the status code returned is expected to be 1 // 137 or 143 is used when stopped by the destroyer. executor.setExitValues(new int[] { 1, 137, 143 }); } try { mojo.getLog().info("Launching Wisdom Server"); mojo.getLog().debug("Command Line: " + cmdLine.toString()); // The message is different whether or not we are in the interactive mode. if (interactive) { mojo.getLog().info("You are in interactive mode"); mojo.getLog().info("Hit 'exit' to shutdown"); } else { mojo.getLog().info("Hit CTRL+C to exit"); } if (debug != 0) { mojo.getLog().info("Wisdom launched with remote debugger interface enabled on port " + debug); } // Block execution until ctrl+c executor.execute(cmdLine); } catch (IOException e) { throw new MojoExecutionException("Cannot execute Wisdom", e); } } /** * Appends the properties from the Maven session (user properties) to the command line. As the command line is * intended to be a Chameleon process, arguments are passed using the {@literal -Dkey=value} syntax. * * @param mojo the mojo * @param cmd the command line to extend */ private static void appendSystemPropertiesToCommandLine(AbstractWisdomMojo mojo, CommandLine cmd) { Properties userProperties = mojo.session.getUserProperties(); if (userProperties != null) { //noinspection unchecked Enumeration<String> names = (Enumeration<String>) userProperties.propertyNames(); while (names.hasMoreElements()) { String name = names.nextElement(); cmd.addArgument("-D" + name + "=" + userProperties.getProperty(name)); } } } /** * Stops a running instance of wisdom using 'chameleon stop'. * * @param mojo the mojo * @throws MojoExecutionException if the instance cannot be stopped */ public void stop(AbstractWisdomMojo mojo) throws MojoExecutionException { File script = new File(mojo.getWisdomRootDirectory(), "chameleon.sh"); if (!script.isFile()) { throw new MojoExecutionException("The 'chameleon.sh' file does not exist in " + mojo.getWisdomRootDirectory().getAbsolutePath() + " - cannot stop the Wisdom instance"); } // If there is a RUNNING_PID file, exit immediately. File pid = new File(mojo.getWisdomRootDirectory(), "RUNNING_PID"); if (!pid.isFile()) { mojo.getLog().info("The RUNNING_PID file does not exist, are you sure Wisdom is running ?"); return; } CommandLine cmdLine = new CommandLine(script); cmdLine.addArgument("stop"); try { mojo.getLog().info("Stopping Wisdom Server using '" + cmdLine.toString() + "'."); // As we know which command line we are executing, we can safely execute the command. Runtime.getRuntime().exec(cmdLine.toStrings(), null, mojo.getWisdomRootDirectory()); //NOSONAR } catch (IOException e) { throw new MojoExecutionException("Cannot stop Wisdom", e); } } /** * Waits for a file to be created. * * @param file the file * @return {@literal true} if the file was created, {@literal false} otherwise */ public static boolean waitForFile(File file) { if (file.isFile()) { return true; } else { // Start waiting 10 seconds maximum long timeout = System.currentTimeMillis() + FILE_WAIT_TIMEOUT; while (System.currentTimeMillis() <= timeout) { sleepQuietly(10); if (file.isFile()) { return true; } } } // Timeout reached return false; } /** * Sleeps for the given amount of time. * * @param time the time */ private static void sleepQuietly(long time) { try { Thread.sleep(time); } catch (InterruptedException e) { // Ignore it. } } /** * Wiats for a file to be deleted. * * @param file the file * @return {@literal true} if the file was deleted, {@literal false} otherwise */ public static boolean waitForFileDeletion(File file) { if (!file.isFile()) { return true; } else { // Start waiting 10 seconds maximum long timeout = System.currentTimeMillis() + FILE_WAIT_TIMEOUT; while (System.currentTimeMillis() <= timeout) { sleepQuietly(10); if (!file.isFile()) { return true; } } } // Timeout reached return false; } }