cvs commit: xml-cocoon2/tools/src/loader Loader.java

[st...@apache.org]

stefano     2003/02/27 14:46:05

  Added:       tools/src/loader Loader.java
  Log:
  The new loader.
  
  I wrote this because Forehead had bugs and I didn't want to add yet another
  dependency on unreleased stuff. I also tried classworlds but it's *PAINFULLY*
  slow at classloading so I wrote my own (which is pretty trivial once you understand
  how classloading and reflection invocation work)
  
  Revision  Changes    Path
  1.1                  xml-cocoon2/tools/src/loader/Loader.java
  
  Index: Loader.java
  ===================================================================
  /*****************************************************************************
   * Copyright (C) The Apache Software Foundation. All rights reserved.        *
   * ------------------------------------------------------------------------- *
   * This software is published under the terms of the Apache Software License *
   * version 1.1, a copy of which has been included  with this distribution in *
   * the LICENSE file.                                                         *
   *****************************************************************************/
  
  import java.io.File;
  
  import java.net.MalformedURLException;
  import java.net.URL;
  import java.net.URLClassLoader;
  
  import java.lang.reflect.InvocationTargetException;
  import java.lang.reflect.Method;
  import java.lang.reflect.Modifier;
  
  import java.util.StringTokenizer;
  
  /**
   * @author <a href="mailto:stefano@apache.org">Stefano Mazzocchi</a>
   * @version CVS $Revision: 1.1 $ $Date: 2003/02/27 22:46:05 $
   */
  public class Loader {
  
      static final boolean VERBOSE = true;
      
      static final String REPOSITORIES = "loader.jar.repositories";
      static final String MAIN_CLASS = "loader.main.class";
      
      class RepositoryClassLoader extends URLClassLoader {
  
          public RepositoryClassLoader(ClassLoader parent) {
              super(new URL[0], parent);
          }
              
          public void addRepository(File repository) {
              if (VERBOSE) System.out.println("Processing repository: " + repository);
  
              if (repository.exists() && repository.isDirectory()) {
                  File[] jars = repository.listFiles();
      
                  for (int i = 0; i < jars.length; i++) {
                      if (jars[i].getAbsolutePath().endsWith(".jar")) {
                          try  {
                              URL url = jars[i].toURL();
                              if (VERBOSE) System.out.println("Adding jar: " + jars[i]);
                              super.addURL(url);                
                          } catch (MalformedURLException e) {
                              throw new IllegalArgumentException(e.toString());
                          }
                      }
                  }
              }
          }
      }
  
      public static void main(String[] args) throws Exception {
          new Loader().run(args);
      }
      
      void run(String[] args) throws Exception 
      {    
          String repositories = System.getProperty(REPOSITORIES);
          if (repositories == null) {
              System.out.println("Loader requires the '" + REPOSITORIES + "' property to be set");
              System.exit(1);
          }
              
          String mainClass = System.getProperty(MAIN_CLASS);
          if (mainClass == null) {
              System.out.println("Loader requires the '" + MAIN_CLASS + "' property to be set");
              System.exit(1);
          }
  
          if (VERBOSE) System.out.println("-------------------- Loading --------------------");
  
          RepositoryClassLoader classLoader = new RepositoryClassLoader(this.getClass().getClassLoader());
  
          StringTokenizer st = new StringTokenizer(repositories,",;:");
          while (st.hasMoreTokens()) {
              classLoader.addRepository(new File(st.nextToken()));        
          }        
  
          Thread.currentThread().setContextClassLoader(classLoader);
  
          if (VERBOSE) System.out.println("-------------------- Executing -----------------");
          if (VERBOSE) System.out.println("Main Class: " + mainClass);
              
          invokeMain(classLoader, mainClass, args);            
      }
          
      void invokeMain(ClassLoader classloader, String classname, String[] args)
      throws IllegalAccessException, InvocationTargetException, NoSuchMethodException, ClassNotFoundException 
      {
          Class invokedClass = classloader.loadClass(classname);
          
          Class[] methodParamTypes = new Class[1];
          methodParamTypes[0] = args.getClass();
          
          Method main = invokedClass.getDeclaredMethod("main", methodParamTypes);
          
          Object[] methodParams = new Object[1];
          methodParams[0] = args;
          
          main.invoke(null, methodParams);
      }    
  }