java.net

Class JarURLConnection

java.lang.Object

java.net.URLConnection

java.net.JarURLConnection

public abstract class JarURLConnection
extends URLConnection

This abstract class represents a common superclass for implementations of jar URL's. A jar URL is a special type of URL that allows JAR files on remote systems to be accessed. It has the form:

jar:<standard URL pointing to jar filei>!/file/within/jarfile

for example:

jar:http://www.urbanophile.com/java/foo.jar!/com/urbanophile/bar.class

That example URL points to the file /com/urbanophile/bar.class in the remote JAR file http://www.urbanophile.com/java/foo.jar. The HTTP protocol is used only as an example. Any supported remote protocol can be used.

This class currently works by retrieving the entire jar file into a local cache file, then performing standard jar operations on it. (At least this is true for the default protocol implementation).

Since:

1.2

Field Summary

Fields

Modifier and Type	Field and Description
protected URLConnection	jarFileURLConnection The connection to the jar file itself.

Fields inherited from class java.net.URLConnection

allowUserInteraction, connected, doInput, doOutput, ifModifiedSince, url, useCaches

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	JarURLConnection(URL url) Creates a JarURLConnection from an URL object

Method Summary

Methods

Modifier and Type	Method and Description
java.util.jar.Attributes	getAttributes() Returns the Attributes for the Jar entry specified by the URL or null if none
java.security.cert.Certificate[]	getCertificates() Returns an array of Certificate objects for the jar file entry specified by this URL or null if there are none
java.lang.String	getEntryName() Returns the "entry name" portion of the jar URL.
java.util.jar.JarEntry	getJarEntry() Returns the entry in this jar file specified by the URL.
abstract java.util.jar.JarFile	getJarFile() Returns a read-only JarFile object for the remote jar file
URL	getJarFileURL() This method returns the "real" URL where the JarFile is located.
java.util.jar.Attributes	getMainAttributes() Returns the main Attributes for the jar file specified in the URL or null if there are none
java.util.jar.Manifest	getManifest() Returns a Manifest object for this jar file, or null if there is no manifest.

Methods inherited from class java.net.URLConnection

addRequestProperty, connect, getAllowUserInteraction, getConnectTimeout, getContent, getContent, getContentEncoding, getContentLength, getContentType, getDate, getDefaultAllowUserInteraction, getDefaultRequestProperty, getDefaultUseCaches, getDoInput, getDoOutput, getExpiration, getFileNameMap, getHeaderField, getHeaderField, getHeaderFieldDate, getHeaderFieldInt, getHeaderFieldKey, getHeaderFields, getIfModifiedSince, getInputStream, getLastModified, getOutputStream, getPermission, getReadTimeout, getRequestProperties, getRequestProperty, getURL, getUseCaches, guessContentTypeFromName, guessContentTypeFromStream, setAllowUserInteraction, setConnectTimeout, setContentHandlerFactory, setDefaultAllowUserInteraction, setDefaultRequestProperty, setDefaultUseCaches, setDoInput, setDoOutput, setFileNameMap, setIfModifiedSince, setReadTimeout, setRequestProperty, setUseCaches, toString

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

jarFileURLConnection

protected URLConnection jarFileURLConnection

The connection to the jar file itself. A JarURLConnection can represent an entry in a jar file or an entire jar file. In either case this describes just the jar file itself.

Constructor Detail

JarURLConnection

protected JarURLConnection(URL url)
                    throws MalformedURLException

Creates a JarURLConnection from an URL object

Parameters:

url - The URL object for this connection.

Throws:

MalformedURLException - If url is invalid

Method Detail

getJarFileURL

public URL getJarFileURL()

This method returns the "real" URL where the JarFile is located. //****Is this right?*****

Returns:

The remote URL

getEntryName

public java.lang.String getEntryName()

Returns the "entry name" portion of the jar URL. This is the portion after the "!/" in the jar URL that represents the pathname inside the actual jar file.

Returns:

The entry name.

getJarEntry

public java.util.jar.JarEntry getJarEntry()
                                   throws java.io.IOException

Returns the entry in this jar file specified by the URL.

Returns:

The jar entry

Throws:

java.io.IOException - If an error occurs

getJarFile

public abstract java.util.jar.JarFile getJarFile()
                                          throws java.io.IOException

Returns a read-only JarFile object for the remote jar file

Returns:

The JarFile object

Throws:

java.io.IOException - If an error occurs

getCertificates

public java.security.cert.Certificate[] getCertificates()
                                                 throws java.io.IOException

Returns an array of Certificate objects for the jar file entry specified by this URL or null if there are none

Returns:

A Certificate array

Throws:

java.io.IOException - If an error occurs

getMainAttributes

public java.util.jar.Attributes getMainAttributes()
                                           throws java.io.IOException

Returns the main Attributes for the jar file specified in the URL or null if there are none

Returns:

The main Attributes for the JAR file for this connection

Throws:

java.io.IOException - If an error occurs

getAttributes

public java.util.jar.Attributes getAttributes()
                                       throws java.io.IOException

Returns the Attributes for the Jar entry specified by the URL or null if none

Returns:

The Attributes object for this connection if the URL for it points to a JAR file entry, null otherwise

Throws:

java.io.IOException - If an error occurs

getManifest

public java.util.jar.Manifest getManifest()
                                   throws java.io.IOException

Returns a Manifest object for this jar file, or null if there is no manifest.

Returns:

The Manifest for this connection, or null if none

Throws:

java.io.IOException - If an error occurs