001/* AppletContext.java -- access the applet's runtime environment
002   Copyright (C) 1999, 2002, 2004 Free Software Foundation, Inc.
003
004This file is part of GNU Classpath.
005
006GNU Classpath is free software; you can redistribute it and/or modify
007it under the terms of the GNU General Public License as published by
008the Free Software Foundation; either version 2, or (at your option)
009any later version.
010
011GNU Classpath is distributed in the hope that it will be useful, but
012WITHOUT ANY WARRANTY; without even the implied warranty of
013MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
014General Public License for more details.
015
016You should have received a copy of the GNU General Public License
017along with GNU Classpath; see the file COPYING.  If not, write to the
018Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
01902110-1301 USA.
020
021Linking this library statically or dynamically with other modules is
022making a combined work based on this library.  Thus, the terms and
023conditions of the GNU General Public License cover the whole
024combination.
025
026As a special exception, the copyright holders of this library give you
027permission to link this library with independent modules to produce an
028executable, regardless of the license terms of these independent
029modules, and to copy and distribute the resulting executable under
030terms of your choice, provided that you also meet, for each linked
031independent module, the terms and conditions of the license of that
032module.  An independent module is a module which is not derived from
033or based on this library.  If you modify this library, you may extend
034this exception to your version of the library, but you are not
035obligated to do so.  If you do not wish to do so, delete this
036exception statement from your version. */
037
038
039package java.applet;
040
041import java.awt.Image;
042import java.io.IOException;
043import java.io.InputStream;
044import java.net.URL;
045import java.util.Enumeration;
046import java.util.Iterator;
047
048/**
049 * This interface allows an applet access to the browser to retrieve
050 * additional data files and display documents.  It also allows the
051 * applet to find out other applets in the same document.
052 *
053 * @author Aaron M. Renn (arenn@urbanophile.com)
054 * @since 1.0
055 * @status updated to 1.5
056 */
057public interface AppletContext
058{
059  /**
060   * Returns an audio clip from the specified URL.
061   *
062   * @param url the URL of the audio clip
063   * @return the retrieved audio clip
064   * @throws NullPointerException if url is null
065   */
066  AudioClip getAudioClip(URL url);
067
068  /**
069   * Returns an image from the specified URL.  Note that the image is not
070   * actually retrieved until the applet attempts to display it, so this
071   * method returns immediately.
072   *
073   * @param url the absolute URL of the image
074   * @return the retrieved image
075   * @throws NullPointerException if url is null
076   */
077  Image getImage(URL url);
078
079  /**
080   * Returns the applet in the document for this object that has the
081   * specified name.
082   *
083   * @param name the applet name
084   * @return the requested applet, or <code>null</code> if not found
085   */
086  Applet getApplet(String name);
087
088  /**
089   * Returns a list of all the applets in the document for this object.
090   *
091   * @return a list of all the applets
092   */
093  Enumeration<Applet> getApplets();
094
095  /**
096   * Displays the web page pointed to by the specified URL in the window
097   * for this object.  This page replaces the document that is currently
098   * there.
099   *
100   * @param url the URL of the web page to load; unspecified on an error
101   */
102  void showDocument(URL url);
103
104  /**
105   * Displays the web page pointed to be the sepcified URL in the window
106   * with the specified name.  The standard names "_top", "_blank",
107   * "_parent", and "_self" are allowed. An applet viewer may disregard
108   * this request.
109   *
110   * @param url the URL of the web page to load
111   * @param target the target window
112   */
113  void showDocument(URL url, String target);
114
115  /**
116   * Displays the specified message in the status window if that window
117   * exists.
118   *
119   * @param message the status message, may be null
120   */
121  void showStatus(String message);
122
123  /**
124   * Associate a stream to a key for this applet context, possibly replacing
125   * the old value. Stream associations are local to the applet context, for
126   * security purposes.
127   *
128   * @param key the key to associate with
129   * @param stream the stream value to tie to the key, or null to remove
130   * @throws IOException if the stream is too large
131   * @since 1.4
132   */
133  void setStream(String key, InputStream stream) throws IOException;
134
135  /**
136   * Return the stream associated with a given key in this applet context, or
137   * null if nothing is associated. Stream associations are local to the
138   * applet context, for security purposes.
139   *
140   * @param key the key to look up
141   * @return the associated stream, or null
142   * @since 1.4
143   */
144  InputStream getStream(String key);
145
146  /**
147   * Iterate over all keys that have associated streams. Stream associated
148   * are local to the applet context, for security purposes.
149   *
150   * @return an iterator over the association keys
151   * @since 1.4
152   */
153  Iterator<String> getStreamKeys();
154} // interface AppletContext