JSeparator


1   /*
2    * @(#)JSeparator.java  1.50 03/12/19
3    *
4    * Copyright 2004 Sun Microsystems, Inc. All rights reserved.
5    * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
6    */
7   
8   package javax.swing;
9   
10  import javax.swing.plaf.*;
11  import javax.accessibility.*;
12  
13  import java.io.ObjectOutputStream  ;
14  import java.io.ObjectInputStream  ;
15  import java.io.IOException  ;
16  
17  
18  /**
19   * <code>JSeparator</code> provides a general purpose component for
20   * implementing divider lines - most commonly used as a divider
21   * between menu items that breaks them up into logical groupings.
22   * Instead of using <code>JSeparator</code> directly,
23   * you can use the <code>JMenu</code> or <code>JPopupMenu</code>
24   * <code>addSeparator</code> method to create and add a separator.
25   * <code>JSeparator</code>s may also be used elsewhere in a GUI
26   * wherever a visual divider is useful.
27   *
28   * <p>
29   *
30   * For more information and examples see
31   * <a
32   href="http://java.sun.com/docs/books/tutorial/uiswing/components/menu.html">How to Use Menus</a>,
33   * a section in <em>The Java Tutorial.</em>
34   * <p>
35   * <strong>Warning:</strong>
36   * Serialized objects of this class will not be compatible with
37   * future Swing releases. The current serialization support is
38   * appropriate for short term storage or RMI between applications running
39   * the same version of Swing.  As of 1.4, support for long term storage
40   * of all JavaBeans<sup><font size="-2">TM</font></sup>
41   * has been added to the <code>java.beans</code> package.
42   * Please see {@link java.beans.XMLEncoder}.
43   *
44   * @beaninfo
45   *      attribute: isContainer false
46   *    description: A divider between menu items.
47   *
48   * @version 1.50 12/19/03
49   * @author Georges Saab
50   * @author Jeff Shapiro
51   */
52  public class JSeparator extends JComponent   implements SwingConstants  , Accessible
53  {
54      /**
55       * @see #getUIClassID
56       * @see #readObject
57       */
58      private static final String   uiClassID = "SeparatorUI";
59  
60      private int orientation = HORIZONTAL;
61  
62      /** Creates a new horizontal separator. */
63      public JSeparator()
64      {
65          this( HORIZONTAL );
66      }
67  
68      /**
69       * Creates a new separator with the specified horizontal or
70       * vertical orientation. 
71       *
72       * @param orientation an integer specifying
73       *      <code>SwingConstants.HORIZONTAL</code> or
74       *          <code>SwingConstants.VERTICAL</code>
75       * @exception IllegalArgumentException if <code>orientation</code>
76       *      is neither <code>SwingConstants.HORIZONTAL</code> nor
77       *      <code>SwingConstants.VERTICAL</code>
78       */
79      public JSeparator( int orientation )
80      {
81          checkOrientation( orientation );
82      this.orientation = orientation;
83      setFocusable(false);
84          updateUI();
85      }
86  
87      /**
88       * Returns the L&F object that renders this component.
89       *
90       * @return the SeparatorUI object that renders this component
91       */
92      public SeparatorUI getUI() {
93          return (SeparatorUI)ui;
94      }
95      
96      /**
97       * Sets the L&F object that renders this component.
98       *
99       * @param ui  the SeparatorUI L&F object
100      * @see UIDefaults#getUI
101      * @beaninfo
102      *        bound: true
103      *       hidden: true
104      *    attribute: visualUpdate true
105      *  description: The UI object that implements the Component's LookAndFeel. 
106      */
107     public void setUI(SeparatorUI ui) {
108         super.setUI(ui);
109     }
110     
111     /**
112      * Resets the UI property to a value from the current look and feel.
113      *
114      * @see JComponent#updateUI
115      */
116     public void updateUI() {
117         setUI((SeparatorUI)UIManager.getUI(this));
118     }
119     
120 
121     /**
122      * Returns the name of the L&F class that renders this component.
123      *
124      * @return the string "SeparatorUI"
125      * @see JComponent#getUIClassID
126      * @see UIDefaults#getUI
127      */
128     public String   getUIClassID() {
129         return uiClassID;
130     }
131 
132 
133     /** 
134      * See <code>readObject</code> and <code>writeObject</code> in
135      * <code>JComponent</code> for more 
136      * information about serialization in Swing.
137      */
138     private void writeObject(ObjectOutputStream   s) throws IOException   {
139         s.defaultWriteObject();
140         if (getUIClassID().equals(uiClassID)) {
141             byte count = JComponent.getWriteObjCounter(this);
142             JComponent.setWriteObjCounter(this, --count);
143             if (count == 0 && ui != null) {
144                 ui.installUI(this);
145             }
146         }
147     }
148 
149     /**
150      * Returns the orientation of this separator.
151      *
152      * @return   The value of the orientation property, one of the 
153      *           following constants defined in <code>SwingConstants</code>:
154      *           <code>VERTICAL</code>, or
155      *           <code>HORIZONTAL</code>.
156      *
157      * @see SwingConstants
158      * @see #setOrientation
159      */
160     public int getOrientation() {
161         return this.orientation;
162     }
163 
164     /**
165      * Sets the orientation of the separator.
166      * The default value of this property is HORIZONTAL.
167      * @param orientation  either <code>SwingConstants.HORIZONTAL</code>
168      *          or <code>SwingConstants.VERTICAL</code>
169      * @exception IllegalArgumentException  if <code>orientation</code>
170      *      is neither <code>SwingConstants.HORIZONTAL</code>
171      *      nor <code>SwingConstants.VERTICAL</code>
172      * 
173      * @see SwingConstants
174      * @see #getOrientation
175      * @beaninfo
176      *        bound: true
177      *    preferred: true
178      *         enum: HORIZONTAL SwingConstants.HORIZONTAL
179      *               VERTICAL   SwingConstants.VERTICAL
180      *    attribute: visualUpdate true
181      *  description: The orientation of the separator.
182      */
183     public void setOrientation( int orientation ) {
184         if (this.orientation == orientation) {
185             return;
186         }
187         int oldValue = this.orientation;
188         checkOrientation( orientation );
189         this.orientation = orientation;
190         firePropertyChange("orientation", oldValue, orientation);
191         revalidate();
192     repaint();
193     }
194 
195     private void checkOrientation( int orientation )
196     {
197         switch ( orientation )
198     {
199             case VERTICAL:
200             case HORIZONTAL:
201                 break;
202             default:
203                 throw new IllegalArgumentException  ( "orientation must be one of: VERTICAL, HORIZONTAL" );
204         }
205     }
206 
207 
208     /**
209      * Returns a string representation of this <code>JSeparator</code>.
210      * This method 
211      * is intended to be used only for debugging purposes, and the 
212      * content and format of the returned string may vary between      
213      * implementations. The returned string may be empty but may not 
214      * be <code>null</code>.
215      * 
216      * @return  a string representation of this <code>JSeparator</code>
217      */
218     protected String   paramString() {
219     String   orientationString = (orientation == HORIZONTAL ?
220                     "HORIZONTAL" : "VERTICAL");
221 
222     return super.paramString() +
223     ",orientation=" + orientationString;
224     }
225 
226 /////////////////
227 // Accessibility support
228 ////////////////
229 
230     /**
231      * Gets the AccessibleContext associated with this JSeparator. 
232      * For separators, the AccessibleContext takes the form of an 
233      * AccessibleJSeparator. 
234      * A new AccessibleJSeparator instance is created if necessary.
235      *
236      * @return an AccessibleJSeparator that serves as the 
237      *         AccessibleContext of this JSeparator
238      */
239     public AccessibleContext getAccessibleContext() {
240         if (accessibleContext == null) {
241             accessibleContext = new AccessibleJSeparator();
242         }
243         return accessibleContext;
244     }
245 
246     /**
247      * This class implements accessibility support for the 
248      * <code>JSeparator</code> class.  It provides an implementation of the 
249      * Java Accessibility API appropriate to separator user-interface elements.
250      * <p>
251      * <strong>Warning:</strong>
252      * Serialized objects of this class will not be compatible with
253      * future Swing releases. The current serialization support is
254      * appropriate for short term storage or RMI between applications running
255      * the same version of Swing.  As of 1.4, support for long term storage
256      * of all JavaBeans<sup><font size="-2">TM</font></sup>
257      * has been added to the <code>java.beans</code> package.
258      * Please see {@link java.beans.XMLEncoder}.
259      */
260     protected class AccessibleJSeparator extends AccessibleJComponent {
261 
262         /**
263          * Get the role of this object.
264          *
265          * @return an instance of AccessibleRole describing the role of the 
266          * object
267          */
268         public AccessibleRole getAccessibleRole() {
269             return AccessibleRole.SEPARATOR;
270         }
271     }
272 }
273
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