gomp-20050608-branch/libjava/java/net/JarURLConnection.java

   1 /* JarURLConnection.java -- Class for manipulating remote jar files
   2    Copyright (C) 1998, 2002, 2003 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 java.net;
  39
  40 import java.io.IOException;
  41 import java.security.cert.Certificate;
  42 import java.util.jar.Attributes;
  43 import java.util.jar.JarEntry;
  44 import java.util.jar.JarFile;
  45 import java.util.jar.JarInputStream;
  46 import java.util.jar.Manifest;
  47 import java.util.zip.ZipEntry;
  48
  49
  50 /**
  51  * This abstract class represents a common superclass for implementations
  52  * of jar URL's.  A jar URL is a special type of URL that allows JAR
  53  * files on remote systems to be accessed.  It has the form:
  54  * <p>
  55  * jar:&lt;standard URL pointing to jar filei&gt;!/file/within/jarfile
  56  * <p> for example:
  57  * <p>
  58  * jar:http://www.urbanophile.com/java/foo.jar!/com/urbanophile/bar.class
  59  * <p>
  60  * That example URL points to the file /com/urbanophile/bar.class in the
  61  * remote JAR file http://www.urbanophile.com/java/foo.jar.  The HTTP
  62  * protocol is used only as an example.  Any supported remote protocol
  63  * can be used.
  64  * <p>
  65  * This class currently works by retrieving the entire jar file into a
  66  * local cache file, then performing standard jar operations on it.
  67  * (At least this is true for the default protocol implementation).
  68  *
  69  * @author Aaron M. Renn (arenn@urbanophile.com)
  70  * @author Kresten Krab Thorup (krab@gnu.org)
  71  * @date Aug 10, 1999.
  72  *
  73  * @since 1.2
  74  */
  75 public abstract class JarURLConnection extends URLConnection
  76 {
  77   /**
  78    * This is the actual URL that points the remote jar file.  This is parsed
  79    * out of the jar URL by the constructor.
  80    */
  81   private final URL jarFileURL;
  82
  83   /**
  84    * The connection to the jar file itself. A JarURLConnection
  85    * can represent an entry in a jar file or an entire jar file.  In
  86    * either case this describes just the jar file itself.
  87    */
  88   protected URLConnection jarFileURLConnection;
  89
  90   /**
  91    * This is the jar file "entry name" or portion after the "!/" in the
  92    * URL which represents the pathname inside the actual jar file.
  93    */
  94   private final String entryName;
  95
  96   /**
  97    * Creates a JarURLConnection from an URL object
  98    *
  99    * @param url The URL object for this connection.
 100    *
 101    * @exception MalformedURLException If url is invalid
 102    *
 103    * @specnote This constructor is protected since JDK 1.4
 104    */
 105   protected JarURLConnection(URL url) throws MalformedURLException
 106   {
 107     super(url);
 108
 109     if (! url.getProtocol().equals("jar"))
 110       throw new MalformedURLException(url + ": Not jar protocol.");
 111
 112     String spec = url.getFile();
 113     int bang = spec.indexOf("!/");
 114     if (bang == -1)
 115       throw new MalformedURLException(url + ": No `!/' in spec.");
 116
 117     // Extract the url for the jar itself.
 118     jarFileURL = new URL(spec.substring(0, bang));
 119
 120     // Get the name of the entry, if any.
 121     entryName = spec.length() == (bang + 2) ? null : spec.substring(bang + 2);
 122   }
 123
 124   /**
 125    * This method returns the "real" URL where the JarFile is located.
 126    * //****Is this right?*****
 127    *
 128    * @return The remote URL
 129    */
 130   public URL getJarFileURL()
 131   {
 132     return jarFileURL;
 133   }
 134
 135   /**
 136    * Returns the "entry name" portion of the jar URL.  This is the portion
 137    * after the "!/" in the jar URL that represents the pathname inside the
 138    * actual jar file.
 139    *
 140    * @return The entry name.
 141    */
 142   public String getEntryName()
 143   {
 144     return entryName;
 145   }
 146
 147   /**
 148    * Returns the entry in this jar file specified by the URL.
 149    *
 150    * @return The jar entry
 151    *
 152    * @exception IOException If an error occurs
 153    */
 154   public JarEntry getJarEntry() throws IOException
 155   {
 156     JarFile jarfile = null;
 157
 158     if (entryName == null)
 159       return null;
 160
 161     if (! doInput)
 162       throw new ProtocolException("Can't open JarEntry if doInput is false");
 163
 164     try
 165       {
 166         jarfile = getJarFile ();
 167       }
 168     catch (IOException x)
 169       {
 170         /* ignore */
 171       }
 172
 173     if (jarfile == null)
 174       {
 175         JarInputStream zis = new JarInputStream(
 176                         jarFileURLConnection.getInputStream ());
 177
 178         // This is hideous, we're doing a linear search for the thing...
 179         for (ZipEntry ent = zis.getNextEntry ();
 180              ent != null;
 181              ent = zis.getNextEntry ())
 182           {
 183             if (entryName.equals (ent.getName()))
 184               {
 185                 return new JarEntry (ent);
 186               }
 187           }
 188       }
 189
 190     else
 191       {
 192         return jarfile.getJarEntry (entryName);
 193       }
 194
 195     return null;
 196   }
 197
 198   /**
 199    * Returns a read-only JarFile object for the remote jar file
 200    *
 201    * @return The JarFile object
 202    *
 203    * @exception IOException If an error occurs
 204    */
 205   public abstract JarFile getJarFile() throws IOException;
 206
 207   /**
 208    * Returns an array of Certificate objects for the jar file entry specified
 209    * by this URL or null if there are none
 210    *
 211    * @return A Certificate array
 212    *
 213    * @exception IOException If an error occurs
 214    */
 215   public Certificate[] getCertificates() throws IOException
 216   {
 217     JarEntry entry = getJarEntry();
 218
 219     return entry != null ? entry.getCertificates() : null;
 220   }
 221
 222   /**
 223    * Returns the main Attributes for the jar file specified in the URL or
 224    * null if there are none
 225    *
 226    * @return The main Attributes for the JAR file for this connection
 227    *
 228    * @exception IOException If an error occurs
 229    */
 230   public Attributes getMainAttributes() throws IOException
 231   {
 232     Manifest manifest = getManifest();
 233
 234     return manifest != null ? manifest.getMainAttributes() : null;
 235   }
 236
 237   /**
 238    * Returns the Attributes for the Jar entry specified by the URL or null
 239    * if none
 240    *
 241    * @return The Attributes object for this connection if the URL for it points
 242    * to a JAR file entry, null otherwise
 243    *
 244    * @exception IOException If an error occurs
 245    */
 246   public Attributes getAttributes() throws IOException
 247   {
 248     JarEntry entry = getJarEntry();
 249
 250     return entry != null ? entry.getAttributes() : null;
 251   }
 252
 253   /**
 254    * Returns a Manifest object for this jar file, or null if there is no
 255    * manifest.
 256    *
 257    * @return The Manifest for this connection, or null if none
 258    *
 259    * @exception IOException If an error occurs
 260    */
 261   public Manifest getManifest() throws IOException
 262   {
 263     JarFile file = getJarFile();
 264
 265     return file != null ? file.getManifest() : null;
 266   }
 267 }