| /* |
| * Copyright (c) 1995, 2013, 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 |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| 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; |
| } |
| } |