Source for gnu.java.net.loader.URLLoader

   1: /* URLLoader.java --  base helper class for URLClassLoader
   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: import java.net.URL;
  42: import java.net.URLClassLoader;
  43: import java.net.URLStreamHandlerFactory;
  44: import java.security.CodeSource;
  45: import java.security.cert.Certificate;
  46: import java.util.ArrayList;
  47: import java.util.jar.Manifest;
  48: 
  49: /**
  50:  * A <code>URLLoader</code> contains all logic to load resources from a
  51:  * given base <code>URL</code>.
  52:  */
  53: public abstract class URLLoader
  54: {
  55:   /**
  56:    * Our classloader to get info from if needed.
  57:    */
  58:   final URLClassLoader classloader;
  59: 
  60:   /**
  61:    * The base URL from which all resources are loaded.
  62:    */
  63:   final URL baseURL;
  64: 
  65:   /**
  66:    * The stream handler factory.
  67:    */
  68:   final URLStreamHandlerFactory factory;
  69: 
  70:   /**
  71:    * The source for stream handlers.
  72:    */
  73:   final URLStreamHandlerCache cache;
  74: 
  75:   /**
  76:    * A <code>CodeSource</code> without any associated certificates.
  77:    * It is common for classes to not have certificates associated
  78:    * with them.  If they come from the same <code>URLLoader</code>
  79:    * then it is safe to share the associated <code>CodeSource</code>
  80:    * between them since <code>CodeSource</code> is immutable.
  81:    */
  82:   final CodeSource noCertCodeSource;
  83: 
  84:   public URLLoader(URLClassLoader classloader, URLStreamHandlerCache cache,
  85:                    URLStreamHandlerFactory factory,
  86:                    URL baseURL)
  87:   {
  88:     this(classloader, cache, factory, baseURL, baseURL);
  89:   }
  90: 
  91:   public URLLoader(URLClassLoader classloader, URLStreamHandlerCache cache,
  92:                    URLStreamHandlerFactory factory,
  93:                    URL baseURL, URL overrideURL)
  94:   {
  95:     this.classloader = classloader;
  96:     this.baseURL = baseURL;
  97:     this.factory = factory;
  98:     this.cache = cache;
  99:     this.noCertCodeSource = new CodeSource(overrideURL, (Certificate[]) null);
 100:   }
 101: 
 102:   /**
 103:    * Return the base URL of this loader.
 104:    */
 105:   public final URL getBaseURL()
 106:   {
 107:     return baseURL;
 108:   }
 109: 
 110:   /**
 111:    * Returns a <code>Class</code> loaded by this
 112:    * <code>URLLoader</code>, or <code>null</code> when this loader
 113:    * either can't load the class or doesn't know how to load classes
 114:    * at all.  Most subclasses do not need to override this; it is only
 115:    * useful in situations where the subclass has a more direct way of
 116:    * making <code>Class</code> objects.
 117:    */
 118:   public Class getClass(String className)
 119:   {
 120:     return null;
 121:   }
 122: 
 123:   /**
 124:    * Returns a <code>Resource</code> loaded by this
 125:    * <code>URLLoader</code>, or <code>null</code> when no
 126:    * <code>Resource</code> with the given name exists.
 127:    */
 128:   public abstract Resource getResource(String s);
 129: 
 130:   /**
 131:    * Returns the <code>Manifest</code> associated with the
 132:    * <code>Resource</code>s loaded by this <code>URLLoader</code> or
 133:    * <code>null</code> there is no such <code>Manifest</code>.
 134:    */
 135:   public Manifest getManifest()
 136:   {
 137:     return null;
 138:   }
 139: 
 140:   /**
 141:    * Return a list of new URLLoader objects representing any
 142:    * class path entries added by this container.
 143:    */
 144:   public ArrayList<URLLoader> getClassPath()
 145:   {
 146:     return null;
 147:   }
 148: }