Package java.net

Source Code of java.net.JarURLConnection

/*
* @(#)JarURLConnection.java  1.35 06/05/16
*
* Copyright 2006 Sun Microsystems, Inc. All rights reserved.
* SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
*/

package java.net;

import java.io.IOException;
import java.util.jar.JarFile;
import java.util.jar.JarEntry;
import java.util.jar.Attributes;
import java.util.jar.Manifest;
import java.security.Permission;
import sun.net.www.ParseUtil;

/**
* A URL Connection to a Java ARchive (JAR) file or an entry in a JAR
* file.
*
* <p>The syntax of a JAR URL is:
*
* <pre>
* jar:&lt;url&gt;!/{entry}
* </pre>
*
* <p>for example:
*
* <p><code>
* jar:http://www.foo.com/bar/baz.jar!/COM/foo/Quux.class<br>
* </code>
*
* <p>Jar URLs should be used to refer to a JAR file or entries in
* a JAR file. The example above is a JAR URL which refers to a JAR
* entry. If the entry name is omitted, the URL refers to the whole
* JAR file:
*
* <code>
* jar:http://www.foo.com/bar/baz.jar!/
* </code>
*
* <p>Users should cast the generic URLConnection to a
* JarURLConnection when they know that the URL they created is a JAR
* URL, and they need JAR-specific functionality. For example:
*
* <pre>
* URL url = new URL("jar:file:/home/duke/duke.jar!/");
* JarURLConnection jarConnection = (JarURLConnection)url.openConnection();
* Manifest manifest = jarConnection.getManifest();
* </pre>
*
* <p>JarURLConnection instances can only be used to read from JAR files.
* It is not possible to get a {@link java.io.OutputStream} to modify or write
* to the underlying JAR file using this class.
* <p>Examples:
*
* <dl>
*
* <dt>A Jar entry
* <dd><code>jar:http://www.foo.com/bar/baz.jar!/COM/foo/Quux.class</code>
*
* <dt>A Jar file
* <dd><code>jar:http://www.foo.com/bar/baz.jar!/</code>
*
* <dt>A Jar directory
* <dd><code>jar:http://www.foo.com/bar/baz.jar!/COM/foo/</code>
*
* </dl>
*
* <p><code>!/</code> is refered to as the <em>separator</em>.
*
* <p>When constructing a JAR url via <code>new URL(context, spec)</code>,
* the following rules apply:
*
* <ul>
*
* <li>if there is no context URL and the specification passed to the
* URL constructor doesn't contain a separator, the URL is considered
* to refer to a JarFile.
*
* <li>if there is a context URL, the context URL is assumed to refer
* to a JAR file or a Jar directory.
*
* <li>if the specification begins with a '/', the Jar directory is
* ignored, and the spec is considered to be at the root of the Jar
* file.
*
* <p>Examples:
*
* <dl>
*
* <dt>context: <b>jar:http://www.foo.com/bar/jar.jar!/</b>,
* spec:<b>baz/entry.txt</b>
*
* <dd>url:<b>jar:http://www.foo.com/bar/jar.jar!/baz/entry.txt</b>
*
* <dt>context: <b>jar:http://www.foo.com/bar/jar.jar!/baz</b>,
* spec:<b>entry.txt</b>
*
* <dd>url:<b>jar:http://www.foo.com/bar/jar.jar!/baz/entry.txt</b>
*
* <dt>context: <b>jar:http://www.foo.com/bar/jar.jar!/baz</b>,
* spec:<b>/entry.txt</b>
*
* <dd>url:<b>jar:http://www.foo.com/bar/jar.jar!/entry.txt</b>
*
* </dl>
*
* </ul>
*
* @see java.net.URL
* @see java.net.URLConnection
*
* @see java.util.jar.JarFile
* @see java.util.jar.JarInputStream
* @see java.util.jar.Manifest
* @see java.util.zip.ZipEntry
*
* @author Benjamin Renaud
* @since 1.2
*/
public abstract class JarURLConnection extends URLConnection {

    private URL jarFileURL;
    private String entryName;

    /**
     * The connection to the JAR file URL, if the connection has been
     * initiated. This should be set by connect.
     */
    protected URLConnection jarFileURLConnection;

    /**
     * Creates the new JarURLConnection to the specified URL.
     * @param url the URL
     * @throws MalformedURLException if no legal protocol
     * could be found in a specification string or the
     * string could not be parsed.
     */

    protected JarURLConnection(URL url) throws MalformedURLException {
  super(url);
  parseSpecs(url);
   

    /* get the specs for a given url out of the cache, and compute and
     * cache them if they're not there.
     */
    private void parseSpecs(URL url) throws MalformedURLException {
  String spec = url.getFile();

  int separator = spec.indexOf("!/");
  /*
   * REMIND: we don't handle nested JAR URLs
   */
  if (separator == -1) {
      throw new MalformedURLException("no !/ found in url spec:" + spec);
  }

  jarFileURL = new URL(spec.substring(0, separator++));
  entryName = null;

  /* if ! is the last letter of the innerURL, entryName is null */
  if (++separator != spec.length()) {
      entryName = spec.substring(separator, spec.length());
      entryName = ParseUtil.decode (entryName);
  }
    }

    /**
     * Returns the URL for the Jar file for this connection.
     *
     * @return the URL for the Jar file for this connection.
     */
    public URL getJarFileURL() {
  return jarFileURL;
    }

    /**  
     * Return the entry name for this connection. This method
     * returns null if the JAR file URL corresponding to this
     * connection points to a JAR file and not a JAR file entry.
     *
     * @return the entry name for this connection, if any. 
     */
    public String getEntryName() {
  return entryName;
    }

    /**  
     * Return the JAR file for this connection.
     *
     * @return the JAR file for this connection. If the connection is
     * a connection to an entry of a JAR file, the JAR file object is
     * returned
     *
     * @exception IOException if an IOException occurs while trying to
     * connect to the JAR file for this connection.
     *
     * @see #connect
     */
    public abstract JarFile getJarFile() throws IOException;

    /**
     * Returns the Manifest for this connection, or null if none.
     *
     * @return the manifest object corresponding to the JAR file object
     * for this connection.
     *
     * @exception IOException if getting the JAR file for this
     * connection causes an IOException to be trown.
     *
     * @see #getJarFile
     */
    public Manifest getManifest() throws IOException {
  return getJarFile().getManifest();
    }
     
    /** 
     * Return the JAR entry object for this connection, if any. This
     * method returns null if the JAR file URL corresponding to this
     * connection points to a JAR file and not a JAR file entry.
     *
     * @return the JAR entry object for this connection, or null if
     * the JAR URL for this connection points to a JAR file.
     *
     * @exception IOException if getting the JAR file for this
     * connection causes an IOException to be trown.
     *
     * @see #getJarFile
     * @see #getJarEntry
     */
    public JarEntry getJarEntry() throws IOException {
  return getJarFile().getJarEntry(entryName);
    }

    /**
     * Return the Attributes object for this connection if the URL
     * for it points to a JAR file entry, null otherwise.
     *
     * @return the Attributes object for this connection if the URL
     * for it points to a JAR file entry, null otherwise. 
     *
     * @exception IOException if getting the JAR entry causes an
     * IOException to be thrown.
     *
     * @see #getJarEntry
     */
    public Attributes getAttributes() throws IOException {
  JarEntry e = getJarEntry();
  return e != null ? e.getAttributes() : null;
    }
 
    /**   
     * Returns the main Attributes for the JAR file for this
     * connection.
     *
     * @return the main Attributes for the JAR file for this
     * connection.
     *
     * @exception IOException if getting the manifest causes an
     * IOException to be thrown.
     *
     * @see #getJarFile
     * @see #getManifest
     */
    public Attributes getMainAttributes() throws IOException {
  Manifest man = getManifest();
  return man != null ? man.getMainAttributes() : null;
    }
  
    /**
     * Return the Certificate object for this connection if the URL
     * for it points to a JAR file entry, null otherwise. This method
     * can only be called once
     * the connection has been completely verified by reading
     * from the input stream until the end of the stream has been
     * reached. Otherwise, this method will return <code>null</code>
     *
     * @return the Certificate object for this connection if the URL
     * for it points to a JAR file entry, null otherwise. 
     *
     * @exception IOException if getting the JAR entry causes an
     * IOException to be thrown.
     *
     * @see #getJarEntry
     */
    public java.security.cert.Certificate[] getCertificates()
   throws IOException
    {
  JarEntry e = getJarEntry();
  return e != null ? e.getCertificates() : null;
    }
}





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