AppletContext


1   /*
2    * @(#)AppletContext.java   1.31 04/05/05
3    *
4    * Copyright 2004 Sun Microsystems, Inc. All rights reserved.
5    * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
6    */
7   
8   package java.applet;
9   
10  import java.awt.Image  ;
11  import java.awt.Graphics  ;
12  import java.awt.image.ColorModel  ;
13  import java.net.URL  ;
14  import java.util.Enumeration  ;
15  import java.io.InputStream  ;
16  import java.io.IOException  ;
17  import java.util.Iterator  ;
18  
19  /**
20   * This interface corresponds to an applet's environment: the
21   * document containing the applet and the other applets in the same
22   * document.
23   * <p>
24   * The methods in this interface can be used by an applet to obtain
25   * information about its environment.
26   *
27   * @author  Arthur van Hoff
28   * @version     1.31, 05/05/04
29   * @since       JDK1.0
30   */
31  public interface AppletContext {
32      /**
33       * Creates an audio clip.
34       *
35       * @param   url   an absolute URL giving the location of the audio clip.
36       * @return  the audio clip at the specified URL.
37       */
38      AudioClip   getAudioClip(URL   url);
39  
40      /**
41       * Returns an <code>Image</code> object that can then be painted on
42       * the screen. The <code>url</code> argument<code> </code>that is
43       * passed as an argument must specify an absolute URL.
44       * <p>
45       * This method always returns immediately, whether or not the image
46       * exists. When the applet attempts to draw the image on the screen,
47       * the data will be loaded. The graphics primitives that draw the
48       * image will incrementally paint on the screen.
49       *
50       * @param   url   an absolute URL giving the location of the image.
51       * @return  the image at the specified URL.
52       * @see     java.awt.Image
53       */
54      Image   getImage(URL   url);
55  
56      /**
57       * Finds and returns the applet in the document represented by this
58       * applet context with the given name. The name can be set in the
59       * HTML tag by setting the <code>name</code> attribute.
60       *
61       * @param   name   an applet name.
62       * @return  the applet with the given name, or <code>null</code> if
63       *          not found.
64       */
65      Applet   getApplet(String   name);
66  
67      /**
68       * Finds all the applets in the document represented by this applet
69       * context.
70       *
71       * @return  an enumeration of all applets in the document represented by
72       *          this applet context.
73       */
74      Enumeration  <Applet  > getApplets();
75  
76      /**
77       * Replaces the Web page currently being viewed with the given URL.
78       * This method may be ignored by applet contexts that are not
79       * browsers.
80       *
81       * @param   url   an absolute URL giving the location of the document.
82       */
83      void showDocument(URL   url);
84  
85      /**
86       * Requests that the browser or applet viewer show the Web page
87       * indicated by the <code>url</code> argument. The
88       * <code>target</code> argument indicates in which HTML frame the
89       * document is to be displayed.
90       * The target argument is interpreted as follows:
91       * <p>
92       * <center><table border="3" summary="Target arguments and their descriptions">
93       * <tr><th>Target Argument</th><th>Description</th></tr>
94       * <tr><td><code>"_self"</code>  <td>Show in the window and frame that
95       *                                   contain the applet.</tr>
96       * <tr><td><code>"_parent"</code><td>Show in the applet's parent frame. If
97       *                                   the applet's frame has no parent frame,
98       *                                   acts the same as "_self".</tr>
99       * <tr><td><code>"_top"</code>   <td>Show in the top-level frame of the applet's
100      *                                   window. If the applet's frame is the
101      *                                   top-level frame, acts the same as "_self".</tr>
102      * <tr><td><code>"_blank"</code> <td>Show in a new, unnamed
103      *                                   top-level window.</tr>
104      * <tr><td><i>name</i><td>Show in the frame or window named <i>name</i>. If
105      *                        a target named <i>name</i> does not already exist, a
106      *                        new top-level window with the specified name is created,
107      *                        and the document is shown there.</tr>
108      * </table> </center>
109      * <p>
110      * An applet viewer or browser is free to ignore <code>showDocument</code>.
111      *
112      * @param   url   an absolute URL giving the location of the document.
113      * @param   target   a <code>String</code> indicating where to display
114      *                   the page.
115      */
116     public void showDocument(URL   url, String   target);
117 
118     /**
119      * Requests that the argument string be displayed in the
120      * "status window". Many browsers and applet viewers
121      * provide such a window, where the application can inform users of
122      * its current state.
123      *
124      * @param   status   a string to display in the status window.
125      */
126     void showStatus(String   status);
127 
128     /**
129      * Associates the specified stream with the specified key in this
130      * applet context. If the applet context previously contained a mapping 
131      * for this key, the old value is replaced. 
132      * <p>
133      * For security reasons, mapping of streams and keys exists for each 
134      * codebase. In other words, applet from one codebase cannot access 
135      * the streams created by an applet from a different codebase
136      * <p>
137      * @param key key with which the specified value is to be associated.
138      * @param stream stream to be associated with the specified key. If this
139      *               parameter is <code>null<code>, the specified key is removed 
140      *               in this applet context.
141      * @throws <code>IOException</code> if the stream size exceeds a certain
142      *         size limit. Size limit is decided by the implementor of this
143      *         interface.
144      * @since JDK1.4
145      */
146     public void setStream(String   key, InputStream   stream)throws IOException  ;
147 
148     /**
149      * Returns the stream to which specified key is associated within this 
150      * applet context. Returns <tt>null</tt> if the applet context contains 
151      * no stream for this key.  
152      * <p>
153      * For security reasons, mapping of streams and keys exists for each 
154      * codebase. In other words, applet from one codebase cannot access 
155      * the streams created by an applet from a different codebase
156      * <p>
157      * @return the stream to which this applet context maps the key
158      * @param key key whose associated stream is to be returned.
159      * @since JDK1.4
160      */
161     public InputStream   getStream(String   key);
162 
163     /**
164      * Finds all the keys of the streams in this applet context.
165      * <p>
166      * For security reasons, mapping of streams and keys exists for each 
167      * codebase. In other words, applet from one codebase cannot access 
168      * the streams created by an applet from a different codebase
169      * <p>
170      * @return  an Iterator of all the names of the streams in this applet 
171      *          context.
172      * @since JDK1.4
173      */
174     public Iterator  <String  > getStreamKeys();
175 }
176
A to Z: JavaDoc & Examples Daily Java News & Articles Open Source Projects Open Source Codes Free Computer Books Remove Frame
Popular Tags