java.net
Class ContentHandler

java.lang.Object
  java.net.ContentHandler

Direct Known Subclasses:

UnknownContentHandler

public abstract class ContentHandler

extends Object

The abstract class ContentHandler is the superclass of all classes that read an Object from a URLConnection.

An application does not generally call the getContent method in this class directly. Instead, an application calls the getContent method in class URL or in URLConnection. The application's content handler factory (an instance of a class that implements the interface ContentHandlerFactory set up by a call to setContentHandler) is called with a String giving the MIME type of the object being received on the socket. The factory returns an instance of a subclass of ContentHandler, and its getContent method is called to create the object.

If no content handler could be found, URLConnection will look for a content handler in a user-defineable set of places. By default it looks in sun.net.www.content, but users can define a vertical-bar delimited set of class prefixes to search through in addition by defining the java.content.handler.pkgs property. The class name must be of the form:

     {package-prefix}.{major}.{minor}
 e.g.
     YoyoDyne.experimental.text.plain
 

If the loading of the content handler class would be performed by a classloader that is outside of the the delegation chain of the caller, the JVM will need the RuntimePermission "getClassLoader".

Since:

JDK1.0

Author:

James Gosling

See Also:

getContent(java.net.URLConnection), ContentHandlerFactory, URL.getContent(), URLConnection, URLConnection.getContent(), URLConnection.setContentHandlerFactory(java.net.ContentHandlerFactory)

Constructor Summary

ContentHandler()

Method Summary

abstract Object	getContent(URLConnection urlc) Given a URL connect stream positioned at the beginning of the representation of an object, this method reads that stream and creates an object from it.
Object	getContent(URLConnection urlc, Class[] classes) Given a URL connect stream positioned at the beginning of the representation of an object, this method reads that stream and creates an object that matches one of the types specified.

Methods inherited from class java.lang.Object

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

Constructor Detail

ContentHandler

public ContentHandler()

Method Detail

getContent

public abstract Object getContent(URLConnection urlc)
                           throws IOException

Given a URL connect stream positioned at the beginning of the representation of an object, this method reads that stream and creates an object from it.

Parameters:

urlc - a URL connection.

Returns:

the object read by the ContentHandler.

Throws:

IOException - if an I/O error occurs while reading the object.

getContent

public Object getContent(URLConnection urlc,
                         Class[] classes)
                  throws IOException

Given a URL connect stream positioned at the beginning of the representation of an object, this method reads that stream and creates an object that matches one of the types specified. The default implementation of this method should call getContent() and screen the return type for a match of the suggested types.

Parameters:

urlc - a URL connection.

classes - an array of types requested

Returns:

the object read by the ContentHandler that is the first match of the suggested types. null if none of the requested are supported.

Throws:

IOException - if an I/O error occurs while reading the object.