Source for gnu.java.net.protocol.file.Handler

   1: /* Handler.java -- "file" protocol handler for java.net
   2:    Copyright (C) 1998, 1999, 2000, 2002, 2003, 2004 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: package gnu.java.net.protocol.file;
  39: 
  40: import java.io.IOException;
  41: import java.net.URL;
  42: import java.net.URLConnection;
  43: import java.net.URLStreamHandler;
  44: 
  45: /**
  46:  * This is the protocol handler for the "file" protocol.
  47:  * It implements the abstract openConnection() method from
  48:  * URLStreamHandler by returning a new FileURLConnection object (from
  49:  * this package).  All other methods are inherited
  50:  *
  51:  * @author Aaron M. Renn (arenn@urbanophile.com)
  52:  * @author Warren Levy (warrenl@cygnus.com)
  53:  */
  54: public class Handler extends URLStreamHandler
  55: {
  56:   /**
  57:    * A do nothing constructor
  58:    */
  59:   public Handler()
  60:   {
  61:   }
  62: 
  63:   /**
  64:    * This method returs a new FileURLConnection for the specified URL
  65:    *
  66:    * @param url The URL to return a connection for
  67:    *
  68:    * @return The URLConnection
  69:    *
  70:    * @exception IOException If an error occurs
  71:    */
  72:   protected URLConnection openConnection(URL url) throws IOException
  73:   {
  74:     // If a hostname is set, then we need to switch protocols to ftp
  75:     // in order to transfer this from the remote host.
  76:     String host = url.getHost();
  77:     if ((host != null) && (! host.equals("")))
  78:       {
  79:         // Reset the protocol (and implicitly the handler) for this URL.
  80:         // Then have the URL attempt the connection again, as it will
  81:         // get the changed handler the next time around.
  82:         // If the ftp protocol handler is not installed, an
  83:         // exception will be thrown from the new openConnection() call.
  84:         setURL (url, "ftp", url.getHost(), url.getPort(), url.getFile(),
  85:                 url.getRef());
  86:         return url.openConnection();
  87:       }
  88: 
  89:     return new Connection(url);
  90:   }
  91: } // class Handler