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25 
26 package java.net;
27 
28 import java.io.IOException;
29 import java.util.jar.JarFile;
30 import java.util.jar.JarEntry;
31 import java.util.jar.Attributes;
32 import java.util.jar.Manifest;
33 import java.security.Permission;
34 import sun.net.www.ParseUtil;
35 
36 /**
37  * A URL Connection to a Java ARchive (JAR) file or an entry in a JAR
38  * file.
39  *
40  * <p>The syntax of a JAR URL is:
41  *
42  * <pre>
43  * jar:&lt;url&gt;!/{entry}
44  * </pre>
45  *
46  * <p>for example:
47  *
48  * <p>{@code jar:http://www.foo.com/bar/baz.jar!/COM/foo/Quux.class}
49  *
50  * <p>Jar URLs should be used to refer to a JAR file or entries in
51  * a JAR file. The example above is a JAR URL which refers to a JAR
52  * entry. If the entry name is omitted, the URL refers to the whole
53  * JAR file:
54  *
55  * {@code jar:http://www.foo.com/bar/baz.jar!/}
56  *
57  * <p>Users should cast the generic URLConnection to a
58  * JarURLConnection when they know that the URL they created is a JAR
59  * URL, and they need JAR-specific functionality. For example:
60  *
61  * <pre>
62  * URL url = new URL("jar:file:/home/duke/duke.jar!/");
63  * JarURLConnection jarConnection = (JarURLConnection)url.openConnection();
64  * Manifest manifest = jarConnection.getManifest();
65  * </pre>
66  *
67  * <p>JarURLConnection instances can only be used to read from JAR files.
68  * It is not possible to get a {@link java.io.OutputStream} to modify or write
69  * to the underlying JAR file using this class.
70  * <p>Examples:
71  *
72  * <dl>
73  *
74  * <dt>A Jar entry
75  * <dd>{@code jar:http://www.foo.com/bar/baz.jar!/COM/foo/Quux.class}
76  *
77  * <dt>A Jar file
78  * <dd>{@code jar:http://www.foo.com/bar/baz.jar!/}
79  *
80  * <dt>A Jar directory
81  * <dd>{@code jar:http://www.foo.com/bar/baz.jar!/COM/foo/}
82  *
83  * </dl>
84  *
85  * <p>{@code !/} is referred to as the <em>separator</em>.
86  *
87  * <p>When constructing a JAR url via {@code new URL(context, spec)},
88  * the following rules apply:
89  *
90  * <ul>
91  *
92  * <li>if there is no context URL and the specification passed to the
93  * URL constructor doesn't contain a separator, the URL is considered
94  * to refer to a JarFile.
95  *
96  * <li>if there is a context URL, the context URL is assumed to refer
97  * to a JAR file or a Jar directory.
98  *
99  * <li>if the specification begins with a '/', the Jar directory is
100  * ignored, and the spec is considered to be at the root of the Jar
101  * file.
102  *
103  * <p>Examples:
104  *
105  * <dl>
106  *
107  * <dt>context: <b>jar:http://www.foo.com/bar/jar.jar!/</b>,
108  * spec:<b>baz/entry.txt</b>
109  *
110  * <dd>url:<b>jar:http://www.foo.com/bar/jar.jar!/baz/entry.txt</b>
111  *
112  * <dt>context: <b>jar:http://www.foo.com/bar/jar.jar!/baz</b>,
113  * spec:<b>entry.txt</b>
114  *
115  * <dd>url:<b>jar:http://www.foo.com/bar/jar.jar!/baz/entry.txt</b>
116  *
117  * <dt>context: <b>jar:http://www.foo.com/bar/jar.jar!/baz</b>,
118  * spec:<b>/entry.txt</b>
119  *
120  * <dd>url:<b>jar:http://www.foo.com/bar/jar.jar!/entry.txt</b>
121  *
122  * </dl>
123  *
124  * </ul>
125  *
126  * @see java.net.URL
127  * @see java.net.URLConnection
128  *
129  * @see java.util.jar.JarFile
130  * @see java.util.jar.JarInputStream
131  * @see java.util.jar.Manifest
132  * @see java.util.zip.ZipEntry
133  *
134  * @author Benjamin Renaud
135  * @since 1.2
136  */
137 public abstract class JarURLConnection extends URLConnection {
138 
139     private URL jarFileURL;
140     private String entryName;
141 
142     /**
143      * The connection to the JAR file URL, if the connection has been
144      * initiated. This should be set by connect.
145      */
146     protected URLConnection jarFileURLConnection;
147 
148     /**
149      * Creates the new JarURLConnection to the specified URL.
150      * @param url the URL
151      * @throws MalformedURLException if no legal protocol
152      * could be found in a specification string or the
153      * string could not be parsed.
154      */
155 
JarURLConnection(URL url)156     protected JarURLConnection(URL url) throws MalformedURLException {
157         super(url);
158         parseSpecs(url);
159     }
160 
161     /* get the specs for a given url out of the cache, and compute and
162      * cache them if they're not there.
163      */
parseSpecs(URL url)164     private void parseSpecs(URL url) throws MalformedURLException {
165         String spec = url.getFile();
166 
167         int separator = spec.indexOf("!/");
168         /*
169          * REMIND: we don't handle nested JAR URLs
170          */
171         if (separator == -1) {
172             throw new MalformedURLException("no !/ found in url spec:" + spec);
173         }
174 
175         jarFileURL = new URL(spec.substring(0, separator++));
176         /*
177          * The url argument may have had a runtime fragment appended, so
178          * we need to add a runtime fragment to the jarFileURL to enable
179          * runtime versioning when the underlying jar file is opened.
180          */
181         if ("runtime".equals(url.getRef())) {
182             jarFileURL = new URL(jarFileURL, "#runtime");
183         }
184         entryName = null;
185 
186         /* if ! is the last letter of the innerURL, entryName is null */
187         if (++separator != spec.length()) {
188             entryName = spec.substring(separator, spec.length());
189             entryName = ParseUtil.decode (entryName);
190         }
191     }
192 
193     /**
194      * Returns the URL for the Jar file for this connection.
195      *
196      * @return the URL for the Jar file for this connection.
197      */
getJarFileURL()198     public URL getJarFileURL() {
199         return jarFileURL;
200     }
201 
202     /**
203      * Return the entry name for this connection. This method
204      * returns null if the JAR file URL corresponding to this
205      * connection points to a JAR file and not a JAR file entry.
206      *
207      * @return the entry name for this connection, if any.
208      */
getEntryName()209     public String getEntryName() {
210         return entryName;
211     }
212 
213     /**
214      * Return the JAR file for this connection.
215      *
216      * @return the JAR file for this connection. If the connection is
217      * a connection to an entry of a JAR file, the JAR file object is
218      * returned
219      *
220      * @exception IOException if an IOException occurs while trying to
221      * connect to the JAR file for this connection.
222      *
223      * @see #connect
224      */
getJarFile()225     public abstract JarFile getJarFile() throws IOException;
226 
227     /**
228      * Returns the Manifest for this connection, or null if none.
229      *
230      * @return the manifest object corresponding to the JAR file object
231      * for this connection.
232      *
233      * @exception IOException if getting the JAR file for this
234      * connection causes an IOException to be thrown.
235      *
236      * @see #getJarFile
237      */
getManifest()238     public Manifest getManifest() throws IOException {
239         return getJarFile().getManifest();
240     }
241 
242     /**
243      * Return the JAR entry object for this connection, if any. This
244      * method returns null if the JAR file URL corresponding to this
245      * connection points to a JAR file and not a JAR file entry.
246      *
247      * @return the JAR entry object for this connection, or null if
248      * the JAR URL for this connection points to a JAR file.
249      *
250      * @exception IOException if getting the JAR file for this
251      * connection causes an IOException to be thrown.
252      *
253      * @see #getJarFile
254      * @see #getJarEntry
255      */
getJarEntry()256     public JarEntry getJarEntry() throws IOException {
257         return entryName == null ? null : getJarFile().getJarEntry(entryName);
258     }
259 
260     /**
261      * Return the Attributes object for this connection if the URL
262      * for it points to a JAR file entry, null otherwise.
263      *
264      * @return the Attributes object for this connection if the URL
265      * for it points to a JAR file entry, null otherwise.
266      *
267      * @exception IOException if getting the JAR entry causes an
268      * IOException to be thrown.
269      *
270      * @see #getJarEntry
271      */
getAttributes()272     public Attributes getAttributes() throws IOException {
273         JarEntry e = getJarEntry();
274         return e != null ? e.getAttributes() : null;
275     }
276 
277     /**
278      * Returns the main Attributes for the JAR file for this
279      * connection.
280      *
281      * @return the main Attributes for the JAR file for this
282      * connection.
283      *
284      * @exception IOException if getting the manifest causes an
285      * IOException to be thrown.
286      *
287      * @see #getJarFile
288      * @see #getManifest
289      */
getMainAttributes()290     public Attributes getMainAttributes() throws IOException {
291         Manifest man = getManifest();
292         return man != null ? man.getMainAttributes() : null;
293     }
294 
295     /**
296      * Return the Certificate object for this connection if the URL
297      * for it points to a JAR file entry, null otherwise. This method
298      * can only be called once
299      * the connection has been completely verified by reading
300      * from the input stream until the end of the stream has been
301      * reached. Otherwise, this method will return {@code null}
302      *
303      * @return the Certificate object for this connection if the URL
304      * for it points to a JAR file entry, null otherwise.
305      *
306      * @exception IOException if getting the JAR entry causes an
307      * IOException to be thrown.
308      *
309      * @see #getJarEntry
310      */
getCertificates()311     public java.security.cert.Certificate[] getCertificates()
312          throws IOException
313     {
314         JarEntry e = getJarEntry();
315         return e != null ? e.getCertificates() : null;
316     }
317 }
318