001/* JarURLConnection.java -- Class for manipulating remote jar files
002   Copyright (C) 1998, 2002, 2003, 2005 Free Software Foundation, Inc.
003
004This file is part of GNU Classpath.
005
006GNU Classpath is free software; you can redistribute it and/or modify
007it under the terms of the GNU General Public License as published by
008the Free Software Foundation; either version 2, or (at your option)
009any later version.
010
011GNU Classpath is distributed in the hope that it will be useful, but
012WITHOUT ANY WARRANTY; without even the implied warranty of
013MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
014General Public License for more details.
015
016You should have received a copy of the GNU General Public License
017along with GNU Classpath; see the file COPYING.  If not, write to the
018Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
01902110-1301 USA.
020
021Linking this library statically or dynamically with other modules is
022making a combined work based on this library.  Thus, the terms and
023conditions of the GNU General Public License cover the whole
024combination.
025
026As a special exception, the copyright holders of this library give you
027permission to link this library with independent modules to produce an
028executable, regardless of the license terms of these independent
029modules, and to copy and distribute the resulting executable under
030terms of your choice, provided that you also meet, for each linked
031independent module, the terms and conditions of the license of that
032module.  An independent module is a module which is not derived from
033or based on this library.  If you modify this library, you may extend
034this exception to your version of the library, but you are not
035obligated to do so.  If you do not wish to do so, delete this
036exception statement from your version. */
037
038package java.net;
039
040import java.io.IOException;
041import java.security.cert.Certificate;
042import java.util.jar.Attributes;
043import java.util.jar.JarEntry;
044import java.util.jar.JarFile;
045import java.util.jar.Manifest;
046
047
048/**
049 * This abstract class represents a common superclass for implementations
050 * of jar URL's.  A jar URL is a special type of URL that allows JAR
051 * files on remote systems to be accessed.  It has the form:
052 * <p>
053 * jar:&lt;standard URL pointing to jar filei&gt;!/file/within/jarfile
054 * <p> for example:
055 * <p>
056 * jar:http://www.urbanophile.com/java/foo.jar!/com/urbanophile/bar.class
057 * <p>
058 * That example URL points to the file /com/urbanophile/bar.class in the
059 * remote JAR file http://www.urbanophile.com/java/foo.jar.  The HTTP
060 * protocol is used only as an example.  Any supported remote protocol
061 * can be used.
062 * <p>
063 * This class currently works by retrieving the entire jar file into a
064 * local cache file, then performing standard jar operations on it.
065 * (At least this is true for the default protocol implementation).
066 *
067 * @author Aaron M. Renn (arenn@urbanophile.com)
068 * @author Kresten Krab Thorup (krab@gnu.org)
069 * @date Aug 10, 1999.
070 *
071 * @since 1.2
072 */
073public abstract class JarURLConnection extends URLConnection
074{
075  /**
076   * This is the actual URL that points the remote jar file.  This is parsed
077   * out of the jar URL by the constructor.
078   */
079  private final URL jarFileURL;
080
081  /**
082   * The connection to the jar file itself. A JarURLConnection
083   * can represent an entry in a jar file or an entire jar file.  In
084   * either case this describes just the jar file itself.
085   */
086  protected URLConnection jarFileURLConnection;
087
088  /**
089   * This is the jar file "entry name" or portion after the "!/" in the
090   * URL which represents the pathname inside the actual jar file.
091   */
092  private final String entryName;
093
094  /**
095   * Creates a JarURLConnection from an URL object
096   *
097   * @param url The URL object for this connection.
098   *
099   * @exception MalformedURLException If url is invalid
100   *
101   * @specnote This constructor is protected since JDK 1.4
102   */
103  protected JarURLConnection(URL url) throws MalformedURLException
104  {
105    super(url);
106
107    if (! url.getProtocol().equals("jar"))
108      throw new MalformedURLException(url + ": Not jar protocol.");
109
110    String spec = url.getFile();
111    int bang = spec.indexOf("!/");
112    if (bang == -1)
113      throw new MalformedURLException(url + ": No `!/' in spec.");
114
115    // Extract the url for the jar itself.
116    jarFileURL = new URL(spec.substring(0, bang));
117
118    // Get the name of the entry, if any.
119    entryName = spec.length() == (bang + 2) ? null : spec.substring(bang + 2);
120  }
121
122  /**
123   * This method returns the "real" URL where the JarFile is located.
124   * //****Is this right?*****
125   *
126   * @return The remote URL
127   */
128  public URL getJarFileURL()
129  {
130    return jarFileURL;
131  }
132
133  /**
134   * Returns the "entry name" portion of the jar URL.  This is the portion
135   * after the "!/" in the jar URL that represents the pathname inside the
136   * actual jar file.
137   *
138   * @return The entry name.
139   */
140  public String getEntryName()
141  {
142    return entryName;
143  }
144
145  /**
146   * Returns the entry in this jar file specified by the URL.
147   *
148   * @return The jar entry
149   *
150   * @exception IOException If an error occurs
151   */
152  public JarEntry getJarEntry() throws IOException
153  {
154    if (entryName == null)
155      return null;
156    JarFile jarFile = getJarFile();
157    return jarFile != null ? jarFile.getJarEntry(entryName) : null;
158  }
159
160  /**
161   * Returns a read-only JarFile object for the remote jar file
162   *
163   * @return The JarFile object
164   *
165   * @exception IOException If an error occurs
166   */
167  public abstract JarFile getJarFile() throws IOException;
168
169  /**
170   * Returns an array of Certificate objects for the jar file entry specified
171   * by this URL or null if there are none
172   *
173   * @return A Certificate array
174   *
175   * @exception IOException If an error occurs
176   */
177  public Certificate[] getCertificates() throws IOException
178  {
179    JarEntry entry = getJarEntry();
180
181    return entry != null ? entry.getCertificates() : null;
182  }
183
184  /**
185   * Returns the main Attributes for the jar file specified in the URL or
186   * null if there are none
187   *
188   * @return The main Attributes for the JAR file for this connection
189   *
190   * @exception IOException If an error occurs
191   */
192  public Attributes getMainAttributes() throws IOException
193  {
194    Manifest manifest = getManifest();
195
196    return manifest != null ? manifest.getMainAttributes() : null;
197  }
198
199  /**
200   * Returns the Attributes for the Jar entry specified by the URL or null
201   * if none
202   *
203   * @return The Attributes object for this connection if the URL for it points
204   * to a JAR file entry, null otherwise
205   *
206   * @exception IOException If an error occurs
207   */
208  public Attributes getAttributes() throws IOException
209  {
210    JarEntry entry = getJarEntry();
211
212    return entry != null ? entry.getAttributes() : null;
213  }
214
215  /**
216   * Returns a Manifest object for this jar file, or null if there is no
217   * manifest.
218   *
219   * @return The Manifest for this connection, or null if none
220   *
221   * @exception IOException If an error occurs
222   */
223  public Manifest getManifest() throws IOException
224  {
225    JarFile file = getJarFile();
226
227    return file != null ? file.getManifest() : null;
228  }
229}