/*
* Copyright (c) 1995, 2006, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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*/
package java.net;
import java.io.IOException;
/** {@collect.stats}
* {@description.open}
* The abstract class <code>ContentHandler</code> is the superclass
* of all classes that read an <code>Object</code> from a
* <code>URLConnection</code>.
* {@description.close}
* {@property.open runtime formal:java.net.ContentHandler_GetContent}
* <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>.
* {@property.close}
* {@description.open}
* 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".
* {@description.close}
*
* @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 {
/** {@collect.stats}
* {@description.open}
* 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.
* {@description.close}
*
* @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;
/** {@collect.stats}
* {@description.open}
* 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.
* {@description.close}
*
* @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;
}
}