java/11 : java.base/java/net/JarURLConnection.java

JarURLConnection
https://openjdk.java.net/
GPLv2 + Classpath Exception
/*
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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
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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.
The syntax of a JAR URL is:
jar:<url>!/{entry}

for example:
jar:http://www.foo.com/bar/baz.jar!/COM/foo/Quux.class 
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: jar:http://www.foo.com/bar/baz.jar!/ 
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:
URL url = new URL("jar:file:/home/duke/duke.jar!/");
JarURLConnection jarConnection = (JarURLConnection)url.openConnection();
Manifest manifest = jarConnection.getManifest();

JarURLConnection instances can only be used to read from JAR files. It is not possible to get a OutputStream to modify or write to the underlying JAR file using this class. 
Examples:

A Jar entry
jar:http://www.foo.com/bar/baz.jar!/COM/foo/Quux.class 
A Jar file
jar:http://www.foo.com/bar/baz.jar!/ 
A Jar directory
jar:http://www.foo.com/bar/baz.jar!/COM/foo/ 
!/ is referred to as the separator.
When constructing a JAR url via new URL(context, spec), the following rules apply: 

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.
if there is a context URL, the context URL is assumed to refer
to a JAR file or a Jar directory.
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.
Examples:

context: jar:http://www.foo.com/bar/jar.jar!/,
spec:baz/entry.txt
url:jar:http://www.foo.com/bar/jar.jar!/baz/entry.txt
context: jar:http://www.foo.com/bar/jar.jar!/baz,
spec:entry.txt
url:jar:http://www.foo.com/bar/jar.jar!/baz/entry.txt
context: jar:http://www.foo.com/bar/jar.jar!/baz,
spec:/entry.txt
url:jar:http://www.foo.com/bar/jar.jar!/entry.txt


Author: Benjamin Renaud
See Also: URL
URLConnection
JarFile
JarInputStream
Manifest
ZipEntry
Since: 1.2/**
 * 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}
 *
 * <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!/}
 *
 * <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}
 *
 * <dt>A Jar file
 * <dd>{@code jar:http://www.foo.com/bar/baz.jar!/}
 *
 * <dt>A Jar directory
 * <dd>{@code jar:http://www.foo.com/bar/baz.jar!/COM/foo/}
 *
 * </dl>
 *
 * <p>{@code !/} is referred to as the <em>separator</em>.
 *
 * <p>When constructing a JAR url via {@code new URL(context, spec)},
 * 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.
/**
     * 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.
Params: url – the URL
Throws: MalformedURLException – if no legal protocol
could be found in a specification string or the
string could not be parsed./**
     * 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++));
        /*
         * The url argument may have had a runtime fragment appended, so
         * we need to add a runtime fragment to the jarFileURL to enable
         * runtime versioning when the underlying jar file is opened.
         */
        if ("runtime".equals(url.getRef())) {
            jarFileURL = new URL(jarFileURL, "#runtime");
        }
        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.
Returns: the URL for the Jar file for this connection./**
     * 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.
Returns: the entry name for this connection, if any./**
     * 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.
Throws: IOException – if an IOException occurs while trying to
connect to the JAR file for this connection.
See Also: URLConnection.connect
Returns: 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/**
     * 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.
Throws: IOException – if getting the JAR file for this
connection causes an IOException to be thrown.
See Also: getJarFile
Returns: the manifest object corresponding to the JAR file object
for this connection./**
     * 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 thrown.
     *
     * @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.
Throws: IOException – if getting the JAR file for this
connection causes an IOException to be thrown.
See Also: getJarFile
getJarEntry
Returns: the JAR entry object for this connection, or null if
the JAR URL for this connection points to a JAR file./**
     * 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 thrown.
     *
     * @see #getJarFile
     * @see #getJarEntry
     */
    public JarEntry getJarEntry() throws IOException {
        return entryName == null ? null : getJarFile().getJarEntry(entryName);
    }

    Return the Attributes object for this connection if the URL
for it points to a JAR file entry, null otherwise.
Throws: IOException – if getting the JAR entry causes an
IOException to be thrown.
See Also: getJarEntry
Returns: 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.
     *
     * @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.
Throws: IOException – if getting the manifest causes an
IOException to be thrown.
See Also: getJarFile
getManifest
Returns: the main Attributes for the JAR file for this
connection./**
     * 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 null 
Throws: IOException – if getting the JAR entry causes an
IOException to be thrown.
See Also: getJarEntry
Returns: the Certificate object for this connection if the URL
for it points to a JAR file entry, null otherwise./**
     * 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}
     *
     * @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;
    }
}
Author:	Benjamin Renaud
See Also:	URL URLConnection JarFile JarInputStream Manifest ZipEntry
Since:	1.2
Params:	url – the URL
Throws:	MalformedURLException – if no legal protocol could be found in a specification string or the string could not be parsed.
Throws:	IOException – if an IOException occurs while trying to connect to the JAR file for this connection.
See Also:	URLConnection.connect
Returns:	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
Throws:	IOException – if getting the JAR file for this connection causes an IOException to be thrown.
See Also:	getJarFile
Returns:	the manifest object corresponding to the JAR file object for this connection.
Throws:	IOException – if getting the JAR entry causes an IOException to be thrown.
See Also:	getJarEntry
Returns:	the Attributes object for this connection if the URL for it points to a JAR file entry, null otherwise.
Throws:	IOException – if getting the manifest causes an IOException to be thrown.
See Also:	getJarFile getManifest
Returns:	the main Attributes for the JAR file for this connection.
/

java/ 11/ java.base/java/net/JarURLConnection.java
