1 /*
2 * Copyright (c) 1995, 2014, 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 1.0
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 *
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 *
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 *
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 }