//
   //  ========================================================================
   //  Copyright (c) 1995-2016 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.osgi.boot.utils;
  
  import java.io.IOException;
  import java.net.URL;
  import java.net.URLClassLoader;
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.Enumeration;
  import java.util.List;
  
  import org.eclipse.jetty.util.log.Log;
  import org.eclipse.jetty.util.log.Logger;
  import org.osgi.framework.Bundle;
  
  /**
   * OSGiClassLoader
   *
   * Class loader that is aware of a bundle. Similar to WebAppClassLoader from Jetty
   * and the OSGiWebAppClassLoader, but works without webapps.
   */
  public class OSGiClassLoader extends URLClassLoader
  {
      private static final Logger LOG = Log.getLogger(OSGiClassLoader.class);
      
      
      private Bundle _bundle;
      private ClassLoader _osgiBundleClassLoader;
      private boolean _lookInOsgiFirst = true;
      private ClassLoader _parent;
      
      /* ------------------------------------------------------------ */
      public OSGiClassLoader(ClassLoader parent, Bundle bundle)
      {
          super(new URL[]{}, parent);
          _parent = getParent();
          _bundle = bundle;
          _osgiBundleClassLoader = BundleClassLoaderHelperFactory.getFactory().getHelper().getBundleClassLoader(_bundle);
      }
      
    
      
      /* ------------------------------------------------------------ */
      /**
       * Get a resource from the classloader
       * 
       * Copied from WebAppClassLoader
       */
      public URL getResource(String name)
      {
          URL url= null;
          boolean tried_parent= false;
  
          
          if (_parent!=null && !_lookInOsgiFirst)
          {
              tried_parent= true;
              
              if (_parent!=null)
                  url= _parent.getResource(name);
          }
  
          if (url == null)
          {           
              url = _osgiBundleClassLoader.getResource(name);
  
              if (url == null && name.startsWith("/"))
              {
                  if (LOG.isDebugEnabled())
                      LOG.debug("HACK leading / off " + name);
  
                  url = _osgiBundleClassLoader.getResource(name.substring(1));
              }
          }
  
          if (url == null && !tried_parent)
          {
              if (_parent!=null)
                  url= _parent.getResource(name);
          }
  
          if (url != null)
             if (LOG.isDebugEnabled())
                 LOG.debug("getResource("+name+")=" + url);
 
         return url;
     }
     
     /* ------------------------------------------------------------ */
     @Override
     public Class<?> loadClass(String name) throws ClassNotFoundException
     {
         return loadClass(name, false);
     }
 
     /* ------------------------------------------------------------ */
     @Override
     protected synchronized Class<?> loadClass(String name, boolean resolve) throws ClassNotFoundException
     {
         Class<?> c = findLoadedClass(name);
         ClassNotFoundException ex= null;
         boolean tried_parent= false;
         
         if (c == null && _parent!=null && !_lookInOsgiFirst)
         {
             tried_parent= true;
             try
             {
                 c= _parent.loadClass(name);
                 if (LOG.isDebugEnabled())
                     LOG.debug("loaded " + c);
             }
             catch (ClassNotFoundException e)
             {
                 ex= e;
             }
         }
 
         if (c == null)
         {
             try
             {
                 c= this.findClass(name);
             }
             catch (ClassNotFoundException e)
             {
                 ex= e;
             }
         }
 
         if (c == null && _parent!=null && !tried_parent)
             c = _parent.loadClass(name);
 
         if (c == null)
             throw ex;
 
         if (resolve)
             resolveClass(c);
 
         if (LOG.isDebugEnabled())
             LOG.debug("loaded " + c+ " from "+c.getClassLoader());
         
         return c;
     }
     
     /* ------------------------------------------------------------ */
     @Override
     public Enumeration<URL> getResources(String name) throws IOException
     {
         Enumeration<URL> osgiUrls = _osgiBundleClassLoader.getResources(name);
         Enumeration<URL> urls = super.getResources(name);
         if (_lookInOsgiFirst)
         {
             return Collections.enumeration(toList(osgiUrls, urls));
         }
         else
         {
             return Collections.enumeration(toList(urls, osgiUrls));
         }
     }
     
     
     /* ------------------------------------------------------------ */
     @Override
     protected Class<?> findClass(String name) throws ClassNotFoundException
     {
         try
         {
             return _lookInOsgiFirst ? _osgiBundleClassLoader.loadClass(name) : super.findClass(name);
         }
         catch (ClassNotFoundException cne)
         {
             try
             {
                 return _lookInOsgiFirst ? super.findClass(name) : _osgiBundleClassLoader.loadClass(name);
             }
             catch (ClassNotFoundException cne2)
             {
                 throw cne;
             }
         }
     }
     
     
     
     
 
    /* ------------------------------------------------------------ */
     /**
      * @param e
      * @param e2
      * @return
      */
     private List<URL> toList(Enumeration<URL> e, Enumeration<URL> e2)
     {
         List<URL> list = new ArrayList<URL>();
         while (e != null && e.hasMoreElements())
             list.add(e.nextElement());
         while (e2 != null && e2.hasMoreElements())
             list.add(e2.nextElement());
         return list;
     }
 }