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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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* accompanied this code).
*
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package java.net;
import java.io.IOException;
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 delegation chain of the caller,
the JVM will need the RuntimePermission "getClassLoader".
Author: James Gosling See Also: Since: JDK1.0
/**
* The abstract class <code>ContentHandler</code> is the superclass
* of all classes that read an <code>Object</code> from a
* <code>URLConnection</code>.
* <p>
* An application does not generally call the
* <code>getContent</code> method in this class directly. Instead, an
* application calls the <code>getContent</code> method in class
* <code>URL</code> or in <code>URLConnection</code>.
* The application's content handler factory (an instance of a class that
* implements the interface <code>ContentHandlerFactory</code> set
* up by a call to <code>setContentHandler</code>) is
* called with a <code>String</code> giving the MIME type of the
* object being received on the socket. The factory returns an
* instance of a subclass of <code>ContentHandler</code>, and its
* <code>getContent</code> method is called to create the object.
* <p>
* 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:
* <pre>
* {package-prefix}.{major}.{minor}
* e.g.
* YoyoDyne.experimental.text.plain
* </pre>
* If the loading of the content handler class would be performed by
* a classloader that is outside of the delegation chain of the caller,
* the JVM will need the RuntimePermission "getClassLoader".
*
* @author James Gosling
* @see java.net.ContentHandler#getContent(java.net.URLConnection)
* @see java.net.ContentHandlerFactory
* @see java.net.URL#getContent()
* @see java.net.URLConnection
* @see java.net.URLConnection#getContent()
* @see java.net.URLConnection#setContentHandlerFactory(java.net.ContentHandlerFactory)
* @since JDK1.0
*/
abstract public class ContentHandler {
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.
Params: - urlc – a URL connection.
Throws: - IOException – if an I/O error occurs while reading the object.
Returns: the object read by the ContentHandler.
/**
* 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.
*
* @param urlc a URL connection.
* @return the object read by the <code>ContentHandler</code>.
* @exception IOException if an I/O error occurs while reading the object.
*/
abstract public 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 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.
Params: - urlc – a URL connection.
- classes – an array of types requested
Throws: - IOException – if an I/O error occurs while reading the object.
Returns: the object read by the ContentHandler that is
the first match of the suggested types.
null if none of the requested are supported. Since: 1.3
/**
* 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.
*
* @param urlc a URL connection.
* @param classes an array of types requested
* @return the object read by the <code>ContentHandler</code> that is
* the first match of the suggested types.
* null if none of the requested are supported.
* @exception IOException if an I/O error occurs while reading the object.
* @since 1.3
*/
public Object getContent(URLConnection urlc, Class[] classes) throws IOException {
Object obj = getContent(urlc);
for (int i = 0; i < classes.length; i++) {
if (classes[i].isInstance(obj)) {
return obj;
}
}
return null;
}
}