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1   /*
2    * Copyright (c) 1995, 2013, Oracle and/or its affiliates. All rights reserved.
3    * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4    *
5    * This code is free software; you can redistribute it and/or modify it
6    * under the terms of the GNU General Public License version 2 only, as
7    * published by the Free Software Foundation.  Oracle designates this
8    * particular file as subject to the "Classpath" exception as provided
9    * by Oracle in the LICENSE file that accompanied this code.
10   *
11   * This code is distributed in the hope that it will be useful, but WITHOUT
12   * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13   * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14   * version 2 for more details (a copy is included in the LICENSE file that
15   * accompanied this code).
16   *
17   * You should have received a copy of the GNU General Public License version
18   * 2 along with this work; if not, write to the Free Software Foundation,
19   * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20   *
21   * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22   * or visit www.oracle.com if you need additional information or have any
23   * questions.
24   */
25  
26  package java.applet;
27  
28  import java.awt.Image;
29  import java.awt.Graphics;
30  import java.awt.image.ColorModel;
31  import java.net.URL;
32  import java.util.Enumeration;
33  import java.io.InputStream;
34  import java.io.IOException;
35  import java.util.Iterator;
36  
37  /**
38   * This interface corresponds to an applet's environment: the
39   * document containing the applet and the other applets in the same
40   * document.
41   * <p>
42   * The methods in this interface can be used by an applet to obtain
43   * information about its environment.
44   *
45   * @author      Arthur van Hoff
46   * @since       JDK1.0
47   */
48  public interface AppletContext {
49      /**
50       * Creates an audio clip.
51       *
52       * @param   url   an absolute URL giving the location of the audio clip.
53       * @return  the audio clip at the specified URL.
54       */
55      AudioClip getAudioClip(URL url);
56  
57      /**
58       * Returns an <code>Image</code> object that can then be painted on
59       * the screen. The <code>url</code> argument that is
60       * passed as an argument must specify an absolute URL.
61       * <p>
62       * This method always returns immediately, whether or not the image
63       * exists. When the applet attempts to draw the image on the screen,
64       * the data will be loaded. The graphics primitives that draw the
65       * image will incrementally paint on the screen.
66       *
67       * @param   url   an absolute URL giving the location of the image.
68       * @return  the image at the specified URL.
69       * @see     java.awt.Image
70       */
71      Image getImage(URL url);
72  
73      /**
74       * Finds and returns the applet in the document represented by this
75       * applet context with the given name. The name can be set in the
76       * HTML tag by setting the <code>name</code> attribute.
77       *
78       * @param   name   an applet name.
79       * @return  the applet with the given name, or <code>null</code> if
80       *          not found.
81       */
82      Applet getApplet(String name);
83  
84      /**
85       * Finds all the applets in the document represented by this applet
86       * context.
87       *
88       * @return  an enumeration of all applets in the document represented by
89       *          this applet context.
90       */
91      Enumeration<Applet> getApplets();
92  
93      /**
94       * Requests that the browser or applet viewer show the Web page
95       * indicated by the <code>url</code> argument. The browser or
96       * applet viewer determines which window or frame to display the
97       * Web page. This method may be ignored by applet contexts that
98       * are not browsers.
99       *
100      * @param   url   an absolute URL giving the location of the document.
101      */
102     void showDocument(URL url);
103 
104     /**
105      * Requests that the browser or applet viewer show the Web page
106      * indicated by the <code>url</code> argument. The
107      * <code>target</code> argument indicates in which HTML frame the
108      * document is to be displayed.
109      * The target argument is interpreted as follows:
110      *
111      * <center><table border="3" summary="Target arguments and their descriptions">
112      * <tr><th>Target Argument</th><th>Description</th></tr>
113      * <tr><td><code>"_self"</code>  <td>Show in the window and frame that
114      *                                   contain the applet.</tr>
115      * <tr><td><code>"_parent"</code><td>Show in the applet's parent frame. If
116      *                                   the applet's frame has no parent frame,
117      *                                   acts the same as "_self".</tr>
118      * <tr><td><code>"_top"</code>   <td>Show in the top-level frame of the applet's
119      *                                   window. If the applet's frame is the
120      *                                   top-level frame, acts the same as "_self".</tr>
121      * <tr><td><code>"_blank"</code> <td>Show in a new, unnamed
122      *                                   top-level window.</tr>
123      * <tr><td><i>name</i><td>Show in the frame or window named <i>name</i>. If
124      *                        a target named <i>name</i> does not already exist, a
125      *                        new top-level window with the specified name is created,
126      *                        and the document is shown there.</tr>
127      * </table> </center>
128      * <p>
129      * An applet viewer or browser is free to ignore <code>showDocument</code>.
130      *
131      * @param   url   an absolute URL giving the location of the document.
132      * @param   target   a <code>String</code> indicating where to display
133      *                   the page.
134      */
135     public void showDocument(URL url, String target);
136 
137     /**
138      * Requests that the argument string be displayed in the
139      * "status window". Many browsers and applet viewers
140      * provide such a window, where the application can inform users of
141      * its current state.
142      *
143      * @param   status   a string to display in the status window.
144      */
145     void showStatus(String status);
146 
147     /**
148      * Associates the specified stream with the specified key in this
149      * applet context. If the applet context previously contained a mapping
150      * for this key, the old value is replaced.
151      * <p>
152      * For security reasons, mapping of streams and keys exists for each
153      * codebase. In other words, applet from one codebase cannot access
154      * the streams created by an applet from a different codebase
155      * <p>
156      * @param key key with which the specified value is to be associated.
157      * @param stream stream to be associated with the specified key. If this
158      *               parameter is <code>null</code>, the specified key is removed
159      *               in this applet context.
160      * @throws IOException if the stream size exceeds a certain
161      *         size limit. Size limit is decided by the implementor of this
162      *         interface.
163      * @since 1.4
164      */
165     public void setStream(String key, InputStream stream)throws IOException;
166 
167     /**
168      * Returns the stream to which specified key is associated within this
169      * applet context. Returns <tt>null</tt> if the applet context contains
170      * no stream for this key.
171      * <p>
172      * For security reasons, mapping of streams and keys exists for each
173      * codebase. In other words, applet from one codebase cannot access
174      * the streams created by an applet from a different codebase
175      * <p>
176      * @return the stream to which this applet context maps the key
177      * @param key key whose associated stream is to be returned.
178      * @since 1.4
179      */
180     public InputStream getStream(String key);
181 
182     /**
183      * Finds all the keys of the streams in this applet context.
184      * <p>
185      * For security reasons, mapping of streams and keys exists for each
186      * codebase. In other words, applet from one codebase cannot access
187      * the streams created by an applet from a different codebase
188      * <p>
189      * @return  an Iterator of all the names of the streams in this applet
190      *          context.
191      * @since 1.4
192      */
193     public Iterator<String> getStreamKeys();
194 }