// ========================================================================
   // Copyright (c) 2002-2009 Mort Bay Consulting Pty. Ltd.
   // ------------------------------------------------------------------------
   // All rights reserved. This program and the accompanying materials
   // are made available under the terms of the Eclipse Public License v1.0
   // and Apache License v2.0 which accompanies this distribution.
   // The Eclipse Public License is available at 
   // http://www.eclipse.org/legal/epl-v10.html
   // The Apache License v2.0 is available at
  // http://www.opensource.org/licenses/apache2.0.php
  // You may elect to redistribute this code under either of these licenses. 
  // ========================================================================
  
  package org.eclipse.jetty.start;
  
  import java.io.File;
  import java.io.IOException;
  import java.io.PrintStream;
  import java.io.UnsupportedEncodingException;
  import java.net.MalformedURLException;
  import java.net.URL;
  import java.net.URLClassLoader;
  import java.util.StringTokenizer;
  import java.util.Vector;
  
  /**
   * Class to handle CLASSPATH construction
   */
  public class Classpath
  {
  
      private final Vector<File> _elements = new Vector<File>();
  
      public Classpath()
      {
      }
  
      public Classpath(String initial)
      {
          addClasspath(initial);
      }
  
      public File[] getElements()
      {
          return _elements.toArray(new File[_elements.size()]);
      }
  
      public int count()
      {
          return _elements.size();
      }
  
      public boolean addComponent(String component)
      {
          if ((component != null) && (component.length() > 0))
          {
              try
              {
                  File f = new File(component);
                  if (f.exists())
                  {
                      File key = f.getCanonicalFile();
                      if (!_elements.contains(key))
                      {
                          _elements.add(key);
                          return true;
                      }
                  }
              }
              catch (IOException e)
              {
              }
          }
          return false;
      }
  
      public boolean addComponent(File component)
      {
          if (component != null)
          {
              try
              {
                  if (component.exists())
                  {
                      File key = component.getCanonicalFile();
                      if (!_elements.contains(key))
                      {
                          _elements.add(key);
                          return true;
                      }
                  }
              }
              catch (IOException e)
              {
              }
          }
          return false;
      }
  
     public boolean addClasspath(String s)
     {
         boolean added = false;
         if (s != null)
         {
             StringTokenizer t = new StringTokenizer(s, File.pathSeparator);
             while (t.hasMoreTokens())
             {
                 added |= addComponent(t.nextToken());
             }
         }
         return added;
     }
 
     public void dump(PrintStream out)
     {
         int i = 0;
         for (File element : _elements)
         {
             out.printf("%2d: %s\n", i++, element.getAbsolutePath());
         }
     }
 
     @Override
     public String toString()
     {
         StringBuffer cp = new StringBuffer(1024);
         int cnt = _elements.size();
         if (cnt >= 1)
         {
             cp.append(((_elements.elementAt(0))).getPath());
         }
         for (int i = 1; i < cnt; i++)
         {
             cp.append(File.pathSeparatorChar);
             cp.append(((_elements.elementAt(i))).getPath());
         }
         return cp.toString();
     }
 
     public ClassLoader getClassLoader()
     {
         int cnt = _elements.size();
         URL[] urls = new URL[cnt];
         for (int i = 0; i < cnt; i++)
         {
             try
             {
                 urls[i] = _elements.elementAt(i).toURI().toURL();
             }
             catch (MalformedURLException e)
             {
             }
         }
 
         ClassLoader parent = Thread.currentThread().getContextClassLoader();
         if (parent == null)
         {
             parent = Classpath.class.getClassLoader();
         }
         if (parent == null)
         {
             parent = ClassLoader.getSystemClassLoader();
         }
         return new Loader(urls, parent);
     }
 
     private static class Loader extends URLClassLoader
     {
         Loader(URL[] urls, ClassLoader parent)
         {
             super(urls, parent);
         }
 
         @Override
         public String toString()
         {
             return "startJarLoader@" + Long.toHexString(hashCode());
         }
     }
 
 
 
     /**
      * Overlay another classpath, copying its elements into place on this
      * Classpath, while eliminating duplicate entries on the classpath.
      * 
      * @param cpOther the other classpath to overlay
      */
     public void overlay(Classpath cpOther)
     {
         for (File otherElement : cpOther._elements)
         {
             if (this._elements.contains(otherElement))
             {
                 // Skip duplicate entries
                 continue;
             }
             this._elements.add(otherElement);
         }
     }
 
     public boolean isEmpty()
     {
         return (_elements == null) || (_elements.isEmpty());
     }
 }