| /* ContentHandler.java -- Abstract class for handling content from URL's |
| Copyright (C) 1998, 1999, 2000, 2001, 2003 Free Software Foundation, Inc. |
| |
| This file is part of GNU Classpath. |
| |
| GNU Classpath is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 2, or (at your option) |
| any later version. |
| |
| GNU Classpath 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 for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with GNU Classpath; see the file COPYING. If not, write to the |
| Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA |
| 02111-1307 USA. |
| |
| Linking this library statically or dynamically with other modules is |
| making a combined work based on this library. Thus, the terms and |
| conditions of the GNU General Public License cover the whole |
| combination. |
| |
| As a special exception, the copyright holders of this library give you |
| permission to link this library with independent modules to produce an |
| executable, regardless of the license terms of these independent |
| modules, and to copy and distribute the resulting executable under |
| terms of your choice, provided that you also meet, for each linked |
| independent module, the terms and conditions of the license of that |
| module. An independent module is a module which is not derived from |
| or based on this library. If you modify this library, you may extend |
| this exception to your version of the library, but you are not |
| obligated to do so. If you do not wish to do so, delete this |
| exception statement from your version. */ |
| |
| package java.net; |
| |
| import java.io.IOException; |
| |
| /** |
| * Written using on-line Java Platform 1.2 API Specification, as well |
| * as "The Java Class Libraries", 2nd edition (Addison-Wesley, 1998). |
| * Status: Believed complete and correct. |
| */ |
| |
| /** |
| * This is an abstract class that is the superclass for classes that read |
| * objects from URL's. Calling the <code>getContent()</code> method in the |
| * <code>URL</code> class or the <code>URLConnection</code> class will cause |
| * an instance of a subclass of <code>ContentHandler</code> to be created for |
| * the MIME type of the object being downloaded from the URL. Thus, this |
| * class is seldom needed by applications/applets directly, but only |
| * indirectly through methods in other classes. |
| * |
| * @author Aaron M. Renn (arenn@urbanophile.com) |
| * @author Warren Levy (warrenl@cygnus.com) |
| */ |
| public abstract class ContentHandler |
| { |
| /* |
| * Constructors |
| */ |
| |
| /** |
| * Default, no-argument constructor. |
| */ |
| public ContentHandler() |
| { |
| } |
| |
| /* |
| * Instance Methods |
| */ |
| |
| /** |
| * This method reads from the <code>InputStream</code> of the passed in URL |
| * connection and uses the data downloaded to create an <code>Object</code> |
| * represening the content. For example, if the URL is pointing to a GIF |
| * file, this method might return an <code>Image</code> object. This method |
| * must be implemented by subclasses. |
| * |
| * @param urlc A <code>URLConnection</code> object to read data from. |
| * |
| * @return An object representing the data read |
| * |
| * @exception IOException If an error occurs |
| */ |
| public abstract Object getContent(URLConnection urlc) |
| throws IOException; |
| |
| /** |
| * This method reads from the <code>InputStream</code> of the passed in URL |
| * connection and uses the data downloaded to create an <code>Object</code> |
| * represening the content. For example, if the URL is pointing to a GIF |
| * file, this method might return an <code>Image</code> object. This method |
| * must be implemented by subclasses. This method uses the list of |
| * supplied classes as candidate types. If the data read doesn't match |
| * any of the supplied type, <code>null</code> is returned. |
| * |
| * @param urlc A <code>URLConnection</code> object to read data from. |
| * @param classes An array of types of objects that are candidate types |
| * for the data to be read. |
| * |
| * @return An object representing the data read, or <code>null</code> |
| * if the data does not match any of the candidate types. |
| * |
| * @exception IOException If an error occurs |
| * |
| * @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; |
| } |
| } // class ContentHandler |