JarURLConnection (Java Platform SE 7 b138)

java.lang.Object
- java.net.URLConnection
- - java.net.JarURLConnection

```
public abstract class JarURLConnection
extends URLConnection
```
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 refered 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
Since:

1.2

See Also:
URL, URLConnection, JarFile, JarInputStream, Manifest, ZipEntry

Field Summary

Fields
Modifier and Type Field and Description

protected URLConnection jarFileURLConnection
The connection to the JAR file URL, if the connection has been initiated.
- Fields inherited from class java.net.URLConnection
  allowUserInteraction, connected, doInput, doOutput, ifModifiedSince, url, useCaches

Fields
Modifier and Type	Field and Description
`protected URLConnection`	`jarFileURLConnection` The connection to the JAR file URL, if the connection has been initiated.

Constructor Summary

Constructors
Modifier Constructor and Description

protected JarURLConnection(URL url)
Creates the new JarURLConnection to the specified URL.

Constructors
Modifier	Constructor and Description
`protected`	`JarURLConnection(URL url)` Creates the new JarURLConnection to the specified URL.

Method Summary

Methods
Modifier and Type	Method and Description
`Attributes`	`getAttributes()` Return the Attributes object for this connection if the URL for it points to a JAR file entry, null otherwise.
`Certificate[]`	`getCertificates()` Return the Certificate object for this connection if the URL for it points to a JAR file entry, null otherwise.
`String`	`getEntryName()` Return the entry name for this connection.
`JarEntry`	`getJarEntry()` Return the JAR entry object for this connection, if any.
`abstract JarFile`	`getJarFile()` Return the JAR file for this connection.
`URL`	`getJarFileURL()` Returns the URL for the Jar file for this connection.
`Attributes`	`getMainAttributes()` Returns the main Attributes for the JAR file for this connection.
`Manifest`	`getManifest()` Returns the Manifest for this connection, or null if none.

Methods inherited from class java.net.URLConnection
addRequestProperty, connect, getAllowUserInteraction, getConnectTimeout, getContent, getContent, getContentEncoding, getContentLength, getContentLengthLong, getContentType, getDate, getDefaultAllowUserInteraction, getDefaultRequestProperty, getDefaultUseCaches, getDoInput, getDoOutput, getExpiration, getFileNameMap, getHeaderField, getHeaderField, getHeaderFieldDate, getHeaderFieldInt, getHeaderFieldKey, getHeaderFieldLong, 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 URL, if the connection has been initiated. This should be set by connect.
- Constructor Detail
  - JarURLConnection
```
protected JarURLConnection(URL url)
                    throws MalformedURLException
```
    Creates the new JarURLConnection to the specified URL.
    
    Parameters:
    url - the URL
    
    Throws:
    
    MalformedURLException - if no legal protocol could be found in a specification string or the string could not be parsed.
- Method Detail
  - getJarFileURL
```
public URL getJarFileURL()
```
    Returns the URL for the Jar file for this connection.
    
    Returns:
    the URL for the Jar file for this connection.
  - getEntryName
```
public String getEntryName()
```
    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.
  - getJarFile
```
public abstract JarFile getJarFile()
                            throws IOException
```
    Return the JAR file for this connection.
    
    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 an IOException occurs while trying to connect to the JAR file for this connection.
    See Also:
    URLConnection.connect()
  - getManifest
```
public Manifest getManifest()
                     throws IOException
```
    Returns the Manifest for this connection, or null if none.
    
    Returns:
    the manifest object corresponding to the JAR file object for this connection.
    
    Throws:
    
    IOException - if getting the JAR file for this connection causes an IOException to be trown.
    See Also:
    getJarFile()
  - getJarEntry
```
public JarEntry getJarEntry()
                     throws IOException
```
    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.
    
    Returns:
    the JAR entry object for this connection, or null if the JAR URL for this connection points to a JAR file.
    
    Throws:
    
    IOException - if getting the JAR file for this connection causes an IOException to be trown.
    See Also:
    getJarFile(), getJarEntry()
  - getAttributes
```
public Attributes getAttributes()
                         throws IOException
```
    Return the Attributes object for this connection if the URL for it points to a JAR file entry, null otherwise.
    
    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 JAR entry causes an IOException to be thrown.
    See Also:
    getJarEntry()
  - getMainAttributes
```
public Attributes getMainAttributes()
                             throws IOException
```
    Returns the main Attributes for the JAR file for this connection.
    
    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()
  - getCertificates
```
public Certificate[] getCertificates()
                              throws IOException
```
    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
    
    Returns:
    the Certificate 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()

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DRAFT ea-b138

Class JarURLConnection

Field Summary

Fields inherited from class java.net.URLConnection

Constructor Summary

Method Summary

Methods inherited from class java.net.URLConnection

Methods inherited from class java.lang.Object

Field Detail

jarFileURLConnection

Constructor Detail

JarURLConnection

Method Detail

getJarFileURL

getEntryName

getJarFile

getManifest

getJarEntry

getAttributes

getMainAttributes

getCertificates