/*

  * 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.

  */

 import java.io.File;

 import java.io.FileInputStream;

 import java.io.FileNotFoundException;

 import java.lang.reflect.Method;

 import java.net.MalformedURLException;

 import java.net.URL;

 import java.net.URLClassLoader;

 import java.net.URLDecoder;

 import java.util.ArrayList;

 import java.util.Properties;

 import java.util.StringTokenizer;

 /**

  * This class is used as a wrapper for loading the

  * org.apache.commons.launcher.Launcher class and invoking its

  * <code>main(String[])</code> method. This particular

  * class is primary used by the Windows 95, 98, ME, and 2000 platforms to

  * overcome the difficulty of putting a jar file directly into the JVM's

  * classpath when using batch scripts on these platforms.

  * <p>

  * Specifically, the problem on thse platforms is when Windows uses the PATH

  * environment variable to find and run a batch script, %0 will resolve

  * incorrectly in that batch script.

  * <p>

  * The way to work around this Windows limitation is to do the following:

  * <ol>

  * <li>Put this class' class file - LauncherBootstrap.class - in the same

  * directory as the batch script. Do not put this class file in a jar file.

  * <li>Put the jar file containing the launcher's classes in the same

  * directory as the batch script and this class' class file. Be sure that

  * that the jar file is named "commons-launcher.jar".

  * <li>Make the Java command in the batch script invoke Java use the following

  * classpath arguments. Be sure to include the quotes to ensure that paths

  * containing spaces are handled properly:

  * <code>-classpath %0\..;"%PATH%"</code>

  * </ol>

  *

  * @author Patrick Luby

  */

 public class LauncherBootstrap {

     //---------------------------------------------------------- Static Fields

     /**

      * Ant classpath property name

      */

     public final static String ANT_CLASSPATH_PROP_NAME = "ant.class.path";

     /**

      * Jar file name

      */

     public final static String LAUNCHER_JAR_FILE_NAME = "commons-launcher.jar";

     /**

      * Properties file name

      */

     public final static String LAUNCHER_PROPS_FILE_NAME = "launcher.properties";

     /**

      * Class name to load

      */

     public final static String LAUNCHER_MAIN_CLASS_NAME = "org.apache.commons.launcher.Launcher";

     /**

      * Cached Laucher class.

      */

     private static Class launcherClass = null;

     //---------------------------------------------------------- Static Methods

     /**

      * The main method.

      *

      * @param args command line arguments

      */

     public static void main(String[] args) {

         try {

             // Try to find the LAUNCHER_JAR_FILE_NAME file in the class

             // loader's and JVM's classpath.

             URL coreURL = LauncherBootstrap.class.getResource("/" + LauncherBootstrap.LAUNCHER_JAR_FILE_NAME);

             if (coreURL == null)

                 throw new FileNotFoundException(LauncherBootstrap.LAUNCHER_JAR_FILE_NAME);

             // Coerce the coreURL's directory into a file

             File coreDir = new File(URLDecoder.decode(coreURL.getFile())).getCanonicalFile().getParentFile();

             // Try to find the LAUNCHER_PROPS_FILE_NAME file in the same

             // directory as this class

             File propsFile = new File(coreDir, LauncherBootstrap.LAUNCHER_PROPS_FILE_NAME);

             if (!propsFile.canRead())

                 throw new FileNotFoundException(propsFile.getPath());

             // Load the properties in the LAUNCHER_PROPS_FILE_NAME 

             Properties props = new Properties();

             FileInputStream fis = new FileInputStream(propsFile);

             props.load(fis);

             fis.close();

             // Create a class loader that contains the Launcher, Ant, and

             // JAXP classes.

             URL[] antURLs = LauncherBootstrap.fileListToURLs((String)props.get(LauncherBootstrap.ANT_CLASSPATH_PROP_NAME));

             URL[] urls = new URL[1 + antURLs.length];

             urls[0] = coreURL;

             for (int i = 0; i < antURLs.length; i++)

                 urls[i + 1] = antURLs[i];

             ClassLoader parentLoader = Thread.currentThread().getContextClassLoader();

             URLClassLoader loader = null;

             if (parentLoader != null)

                 loader = new URLClassLoader(urls, parentLoader);

             else

                 loader = new URLClassLoader(urls);

             // Load the LAUNCHER_MAIN_CLASS_NAME class

             launcherClass = loader.loadClass(LAUNCHER_MAIN_CLASS_NAME);

             // Get the LAUNCHER_MAIN_CLASS_NAME class' getLocalizedString()

             // method as we need it for printing the usage statement

             Method getLocalizedStringMethod = launcherClass.getDeclaredMethod("getLocalizedString", new Class[]{ String.class });

             // Invoke the LAUNCHER_MAIN_CLASS_NAME class' start() method.

             // If the ant.class.path property is not set correctly in the 

             // LAUNCHER_PROPS_FILE_NAME, this will throw an exception.

             Method startMethod = launcherClass.getDeclaredMethod("start", new Class[]{ String[].class });

             int returnValue = ((Integer)startMethod.invoke(null, new Object[]{ args })).intValue();

             // Always exit cleanly after invoking the start() method

             System.exit(returnValue);

        } catch (Throwable t) {

            t.printStackTrace();

            System.exit(1);

         }

     }

     /**

      * Convert a ":" separated list of URL file fragments into an array of URL

      * objects. Note that any all URL file fragments must conform to the format

      * required by the "file" parameter in the

      * {@link URL(String, String, String)} constructor.

      *

      * @param fileList the ":" delimited list of URL file fragments to be

      *  converted

      * @return an array of URL objects

      * @throws MalformedURLException if the fileList parameter contains any

      *  malformed URLs

      */

     private static URL[] fileListToURLs(String fileList)

         throws MalformedURLException

     {

         if (fileList == null || "".equals(fileList))

             return new URL[0];

         // Parse the path string

         ArrayList list = new ArrayList();

         StringTokenizer tokenizer = new StringTokenizer(fileList, ":");

         URL bootstrapURL = LauncherBootstrap.class.getResource("/" + LauncherBootstrap.class.getName() + ".class");

         while (tokenizer.hasMoreTokens())

             list.add(new URL(bootstrapURL, tokenizer.nextToken()));

         return (URL[])list.toArray(new URL[list.size()]);

     }

 }