java.net

Class JarURLConnection

java.lang.Object

java.net.URLConnection

java.net.JarURLConnection

Direct Known Subclasses:

JarURLConnectionImpl

public abstract class JarURLConnection
extends URLConnection

This class establishes a connection to a jar: URL using the JAR protocol. A JarURLConnection instance can refer to either a JAR archive file or to an entry of such a file. jar: URLs are specified as follows: jar:{archive-url}!/{entry} where "!/" is called a separator. This separator is important to determine if an archive or an entry of an archive is referred.

Examples:

• Archive: jar:http://www.example.com/applets/archive.jar!/
• File Entry: jar:http://www.example.com/applets/archive.jar!/test.class
• Directory Entry: jar:http://www.example.com/applets/archive.jar!/applets/

This class has different behavior depending on the URLConnection.getUseCaches() setting. When caching is enabled the underlying JarFile returned from getJarFile() is cached and shared between connections. It must not be closed by the caller. Disabling caching using URLConnection.setUseCaches(boolean) will prevent sharing but in the absence of a JarURLConnection.disconnect() method the only way to close the underlying JarFile is to call getJarFile().close() or getInputStream().close(). For uncached connections, closing the JarFile can prevent various other URLConnection methods from working.

Field Summary

Fields

Modifier and Type	Field and Description
protected URLConnection	jarFileURLConnection The location part of the represented URL.

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) Constructs an instance of JarURLConnection that refers to the specified URL.

Method Summary

Modifier and Type	Method and Description
Attributes	getAttributes() Returns all attributes of the JarEntry referenced by this JarURLConnection.
Certificate[]	getCertificates() Returns all certificates of the JarEntry referenced by this JarURLConnection instance.
String	getEntryName() Gets the name of the entry referenced by this JarURLConnection.
JarEntry	getJarEntry() Gets the JarEntry object of the entry referenced by this JarURLConnection.
abstract JarFile	getJarFile() Gets the JarFile object referenced by this JarURLConnection.
URL	getJarFileURL() Gets the URL to the JAR-file referenced by this JarURLConnection.
Attributes	getMainAttributes() Gets all attributes of the manifest file referenced by this JarURLConnection.
Manifest	getManifest() Gets the manifest file associated with this JAR-URL.

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 location part of the represented URL.

Constructor Detail

JarURLConnection

protected JarURLConnection(URL url)
                    throws MalformedURLException

Constructs an instance of JarURLConnection that refers to the specified URL.

Parameters:

url - the URL that contains the location to connect to.

Throws:

MalformedURLException - if an invalid URL has been entered.

Method Detail

getAttributes

public Attributes getAttributes()
                         throws IOException

Returns all attributes of the JarEntry referenced by this JarURLConnection.

Returns:

the attributes of the referenced JarEntry.

Throws:

IOException - if an I/O exception occurs while retrieving the JAR-entries.

getCertificates

public Certificate[] getCertificates()
                              throws IOException

Returns all certificates of the JarEntry referenced by this JarURLConnection instance. This method will return null until the InputStream has been completely verified.

Returns:

the certificates of the JarEntry as an array.

Throws:

IOException - if there is an I/O exception occurs while getting the JarEntry.

getEntryName

public String getEntryName()

Gets the name of the entry referenced by this JarURLConnection. The return value will be null if this instance refers to a JAR file rather than an JAR file entry.

Returns:

the JarEntry name this instance refers to.

getJarEntry

public JarEntry getJarEntry()
                     throws IOException

Gets the JarEntry object of the entry referenced by this JarURLConnection.

Returns:

the referenced JarEntry object or null if no entry name is specified.

Throws:

IOException - if an error occurs while getting the file or file-entry.

getManifest

public Manifest getManifest()
                     throws IOException

Gets the manifest file associated with this JAR-URL.

Returns:

the manifest of the referenced JAR-file.

Throws:

IOException - if an error occurs while getting the manifest file.

getJarFile

public abstract JarFile getJarFile()
                            throws IOException

Gets the JarFile object referenced by this JarURLConnection.

Returns:

the referenced JarFile object.

Throws:

IOException - if an I/O exception occurs while retrieving the JAR-file.

getJarFileURL

public URL getJarFileURL()

Gets the URL to the JAR-file referenced by this JarURLConnection.

Returns:

the URL to the JAR-file or null if there was an error retrieving the URL.

getMainAttributes

public Attributes getMainAttributes()
                             throws IOException

Gets all attributes of the manifest file referenced by this JarURLConnection. If this instance refers to a JAR-file rather than a JAR-file entry, null will be returned.

Returns:

the attributes of the manifest file or null.

Throws:

IOException - if an I/O exception occurs while retrieving the JarFile.