Source for gnu.java.net.loader.RemoteURLLoader

   1: /* RemoteURLLoader.java -- a URLLoader for "remote" objects
   2:    Copyright (C) 2006 Free Software Foundation, Inc.
   3: 
   4: This file is part of GNU Classpath.
   5: 
   6: GNU Classpath is free software; you can redistribute it and/or modify
   7: it under the terms of the GNU General Public License as published by
   8: the Free Software Foundation; either version 2, or (at your option)
   9: any later version.
  10: 
  11: GNU Classpath is distributed in the hope that it will be useful, but
  12: WITHOUT ANY WARRANTY; without even the implied warranty of
  13: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14: General Public License for more details.
  15: 
  16: You should have received a copy of the GNU General Public License
  17: along with GNU Classpath; see the file COPYING.  If not, write to the
  18: Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  19: 02110-1301 USA.
  20: 
  21: Linking this library statically or dynamically with other modules is
  22: making a combined work based on this library.  Thus, the terms and
  23: conditions of the GNU General Public License cover the whole
  24: combination.
  25: 
  26: As a special exception, the copyright holders of this library give you
  27: permission to link this library with independent modules to produce an
  28: executable, regardless of the license terms of these independent
  29: modules, and to copy and distribute the resulting executable under
  30: terms of your choice, provided that you also meet, for each linked
  31: independent module, the terms and conditions of the license of that
  32: module.  An independent module is a module which is not derived from
  33: or based on this library.  If you modify this library, you may extend
  34: this exception to your version of the library, but you are not
  35: obligated to do so.  If you do not wish to do so, delete this
  36: exception statement from your version. */
  37: 
  38: 
  39: package gnu.java.net.loader;
  40: 
  41: 
  42: import java.io.IOException;
  43: import java.io.InputStream;
  44: import java.net.HttpURLConnection;
  45: import java.net.URL;
  46: import java.net.URLClassLoader;
  47: import java.net.URLConnection;
  48: import java.net.URLStreamHandlerFactory;
  49: 
  50: /**
  51:  * Loader for remote directories.
  52:  */
  53: public final class RemoteURLLoader extends URLLoader
  54: {
  55:   private final String protocol;
  56: 
  57:   public RemoteURLLoader(URLClassLoader classloader,
  58:                          URLStreamHandlerCache cache,
  59:                          URLStreamHandlerFactory factory,
  60:                          URL url)
  61:   {
  62:     super(classloader, cache, factory, url);
  63:     protocol = url.getProtocol();
  64:   }
  65: 
  66:   /**
  67:    * Get a remote resource.
  68:    * Returns null if no such resource exists.
  69:    */
  70:   public Resource getResource(String name)
  71:   {
  72:     try
  73:       {
  74:         URL url = new URL(baseURL, name, cache.get(factory, protocol));
  75:         URLConnection connection = url.openConnection();
  76: 
  77:         // Open the connection and check the stream
  78:         // just to be sure it exists.
  79:         int length = connection.getContentLength();
  80:         InputStream stream = connection.getInputStream();
  81: 
  82:         // We can do some extra checking if it is a http request
  83:         if (connection instanceof HttpURLConnection)
  84:           {
  85:             int response =
  86:               ((HttpURLConnection) connection).getResponseCode();
  87:             if (response / 100 != 2)
  88:               return null;
  89:           }
  90: 
  91:         if (stream != null)
  92:           return new RemoteResource(this, name, url, stream, length);
  93:         else
  94:           return null;
  95:       }
  96:     catch (IOException ioe)
  97:       {
  98:         return null;
  99:       }
 100:   }
 101: }