/*
 * Copyright (c) 1995, 2013, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 */

package java.net;

import java.io.IOException;

/**
 * The abstract class {@code ContentHandler} is the superclass
 * of all classes that read an {@code Object} from a
 * {@code URLConnection}.
 * <p>
 * An application does not generally call the
 * {@code getContent} method in this class directly. Instead, an
 * application calls the {@code getContent} method in class
 * {@code URL} or in {@code URLConnection}.
 * The application's content handler factory (an instance of a class that
 * implements the interface {@code ContentHandlerFactory} set up by a call to
 * {@link URLConnection#setContentHandlerFactory(ContentHandlerFactory)
 * setContentHandlerFactory} is called with a {@code String} giving the
 * MIME type of the object being received on the socket. The factory returns an
 * instance of a subclass of {@code ContentHandler}, and its
 * {@code getContent} method is called to create the object.
 * <p>
 * If no content handler could be {@linkplain URLConnection#getContent() found},
 * URLConnection will look for a content handler in a user-definable set of places.
 * Users can define a vertical-bar delimited set of class prefixes
 * to search through by defining the <i>{@link java.net.URLConnection#contentPathProp}</i>
 * property. The class name must be of the form:
 * <blockquote>
 * <i>{package-prefix}.{major}.{minor}</i>
 * <p>
 * where <i>{major}.{minor}</i> is formed by taking the
 * content-type string, replacing all slash characters with a
 * {@code period} ('.'), and all other non-alphanumeric characters
 * with the underscore character '{@code _}'. The alphanumeric
 * characters are specifically the 26 uppercase ASCII letters
 * '{@code A}' through '{@code Z}', the 26 lowercase ASCII
 * letters '{@code a}' through '{@code z}', and the 10 ASCII
 * digits '{@code 0}' through '{@code 9}'.
 * <p>
 * e.g.
 * YoyoDyne.experimental.text.plain
 * </blockquote>
 * If no user-defined content handler is found, then the system
 * tries to load a specific <i>content-type</i> handler from one
 * of the built-in handlers, if one exists.
 * <p>
 * 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 1.0
 */
public abstract 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.
 *
 * @param urlc a URL connection.
 * @return the object read by the {@code ContentHandler}.
 * @exception IOException if an I/O error occurs while reading the object.
 */
 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 that matches one of the types specified.
 *
 * The default implementation of this method should call
 * {@link #getContent(URLConnection)}
 * 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} that is
 * the first match of the suggested types or
 * {@code null} if none of the requested are supported.
 * @exception IOException if an I/O error occurs while reading the object.
 * @since 1.3
 */
 @SuppressWarnings("rawtypes")
 public Object getContent(URLConnection urlc, Class[] classes) throws IOException {
 Object obj = getContent(urlc);

 for (Class<?> c : classes) {
 if (c.isInstance(obj)) {
 return obj;
 }
 }
 return null;
 }
}