001 /* JarURLConnection.java -- Class for manipulating remote jar files
002 Copyright (C) 1998, 2002, 2003, 2005 Free Software Foundation, Inc.
003
004 This file is part of GNU Classpath.
005
006 GNU Classpath is free software; you can redistribute it and/or modify
007 it under the terms of the GNU General Public License as published by
008 the Free Software Foundation; either version 2, or (at your option)
009 any later version.
010
011 GNU Classpath is distributed in the hope that it will be useful, but
012 WITHOUT ANY WARRANTY; without even the implied warranty of
013 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
014 General Public License for more details.
015
016 You should have received a copy of the GNU General Public License
017 along with GNU Classpath; see the file COPYING. If not, write to the
018 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
019 02110-1301 USA.
020
021 Linking this library statically or dynamically with other modules is
022 making a combined work based on this library. Thus, the terms and
023 conditions of the GNU General Public License cover the whole
024 combination.
025
026 As a special exception, the copyright holders of this library give you
027 permission to link this library with independent modules to produce an
028 executable, regardless of the license terms of these independent
029 modules, and to copy and distribute the resulting executable under
030 terms of your choice, provided that you also meet, for each linked
031 independent module, the terms and conditions of the license of that
032 module. An independent module is a module which is not derived from
033 or based on this library. If you modify this library, you may extend
034 this exception to your version of the library, but you are not
035 obligated to do so. If you do not wish to do so, delete this
036 exception statement from your version. */
037
038 package java.net;
039
040 import java.io.IOException;
041 import java.security.cert.Certificate;
042 import java.util.jar.Attributes;
043 import java.util.jar.JarEntry;
044 import java.util.jar.JarFile;
045 import 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:<standard URL pointing to jar filei>!/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 */
073 public 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 }