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    1   /*
    2    * Copyright (c) 1997, 2006, 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 javax.swing;
   27   
   28   import javax.swing.plaf;
   29   import javax.accessibility;
   30   
   31   import java.io.ObjectOutputStream;
   32   import java.io.ObjectInputStream;
   33   import java.io.IOException;
   34   
   35   
   36   /**
   37    * <code>JSeparator</code> provides a general purpose component for
   38    * implementing divider lines - most commonly used as a divider
   39    * between menu items that breaks them up into logical groupings.
   40    * Instead of using <code>JSeparator</code> directly,
   41    * you can use the <code>JMenu</code> or <code>JPopupMenu</code>
   42    * <code>addSeparator</code> method to create and add a separator.
   43    * <code>JSeparator</code>s may also be used elsewhere in a GUI
   44    * wherever a visual divider is useful.
   45    *
   46    * <p>
   47    *
   48    * For more information and examples see
   49    * <a
   50    href="http://java.sun.com/docs/books/tutorial/uiswing/components/menu.html">How to Use Menus</a>,
   51    * a section in <em>The Java Tutorial.</em>
   52    * <p>
   53    * <strong>Warning:</strong> Swing is not thread safe. For more
   54    * information see <a
   55    * href="package-summary.html#threading">Swing's Threading
   56    * Policy</a>.
   57    * <p>
   58    * <strong>Warning:</strong>
   59    * Serialized objects of this class will not be compatible with
   60    * future Swing releases. The current serialization support is
   61    * appropriate for short term storage or RMI between applications running
   62    * the same version of Swing.  As of 1.4, support for long term storage
   63    * of all JavaBeans<sup><font size="-2">TM</font></sup>
   64    * has been added to the <code>java.beans</code> package.
   65    * Please see {@link java.beans.XMLEncoder}.
   66    *
   67    * @beaninfo
   68    *      attribute: isContainer false
   69    *    description: A divider between menu items.
   70    *
   71    * @author Georges Saab
   72    * @author Jeff Shapiro
   73    */
   74   public class JSeparator extends JComponent implements SwingConstants, Accessible
   75   {
   76       /**
   77        * @see #getUIClassID
   78        * @see #readObject
   79        */
   80       private static final String uiClassID = "SeparatorUI";
   81   
   82       private int orientation = HORIZONTAL;
   83   
   84       /** Creates a new horizontal separator. */
   85       public JSeparator()
   86       {
   87           this( HORIZONTAL );
   88       }
   89   
   90       /**
   91        * Creates a new separator with the specified horizontal or
   92        * vertical orientation.
   93        *
   94        * @param orientation an integer specifying
   95        *          <code>SwingConstants.HORIZONTAL</code> or
   96        *          <code>SwingConstants.VERTICAL</code>
   97        * @exception IllegalArgumentException if <code>orientation</code>
   98        *          is neither <code>SwingConstants.HORIZONTAL</code> nor
   99        *          <code>SwingConstants.VERTICAL</code>
  100        */
  101       public JSeparator( int orientation )
  102       {
  103           checkOrientation( orientation );
  104           this.orientation = orientation;
  105           setFocusable(false);
  106           updateUI();
  107       }
  108   
  109       /**
  110        * Returns the L&F object that renders this component.
  111        *
  112        * @return the SeparatorUI object that renders this component
  113        */
  114       public SeparatorUI getUI() {
  115           return (SeparatorUI)ui;
  116       }
  117   
  118       /**
  119        * Sets the L&F object that renders this component.
  120        *
  121        * @param ui  the SeparatorUI L&F object
  122        * @see UIDefaults#getUI
  123        * @beaninfo
  124        *        bound: true
  125        *       hidden: true
  126        *    attribute: visualUpdate true
  127        *  description: The UI object that implements the Component's LookAndFeel.
  128        */
  129       public void setUI(SeparatorUI ui) {
  130           super.setUI(ui);
  131       }
  132   
  133       /**
  134        * Resets the UI property to a value from the current look and feel.
  135        *
  136        * @see JComponent#updateUI
  137        */
  138       public void updateUI() {
  139           setUI((SeparatorUI)UIManager.getUI(this));
  140       }
  141   
  142   
  143       /**
  144        * Returns the name of the L&F class that renders this component.
  145        *
  146        * @return the string "SeparatorUI"
  147        * @see JComponent#getUIClassID
  148        * @see UIDefaults#getUI
  149        */
  150       public String getUIClassID() {
  151           return uiClassID;
  152       }
  153   
  154   
  155       /**
  156        * See <code>readObject</code> and <code>writeObject</code> in
  157        * <code>JComponent</code> for more
  158        * information about serialization in Swing.
  159        */
  160       private void writeObject(ObjectOutputStream s) throws IOException {
  161           s.defaultWriteObject();
  162           if (getUIClassID().equals(uiClassID)) {
  163               byte count = JComponent.getWriteObjCounter(this);
  164               JComponent.setWriteObjCounter(this, --count);
  165               if (count == 0 && ui != null) {
  166                   ui.installUI(this);
  167               }
  168           }
  169       }
  170   
  171       /**
  172        * Returns the orientation of this separator.
  173        *
  174        * @return   The value of the orientation property, one of the
  175        *           following constants defined in <code>SwingConstants</code>:
  176        *           <code>VERTICAL</code>, or
  177        *           <code>HORIZONTAL</code>.
  178        *
  179        * @see SwingConstants
  180        * @see #setOrientation
  181        */
  182       public int getOrientation() {
  183           return this.orientation;
  184       }
  185   
  186       /**
  187        * Sets the orientation of the separator.
  188        * The default value of this property is HORIZONTAL.
  189        * @param orientation  either <code>SwingConstants.HORIZONTAL</code>
  190        *                  or <code>SwingConstants.VERTICAL</code>
  191        * @exception IllegalArgumentException  if <code>orientation</code>
  192        *          is neither <code>SwingConstants.HORIZONTAL</code>
  193        *          nor <code>SwingConstants.VERTICAL</code>
  194        *
  195        * @see SwingConstants
  196        * @see #getOrientation
  197        * @beaninfo
  198        *        bound: true
  199        *    preferred: true
  200        *         enum: HORIZONTAL SwingConstants.HORIZONTAL
  201        *               VERTICAL   SwingConstants.VERTICAL
  202        *    attribute: visualUpdate true
  203        *  description: The orientation of the separator.
  204        */
  205       public void setOrientation( int orientation ) {
  206           if (this.orientation == orientation) {
  207               return;
  208           }
  209           int oldValue = this.orientation;
  210           checkOrientation( orientation );
  211           this.orientation = orientation;
  212           firePropertyChange("orientation", oldValue, orientation);
  213           revalidate();
  214           repaint();
  215       }
  216   
  217       private void checkOrientation( int orientation )
  218       {
  219           switch ( orientation )
  220           {
  221               case VERTICAL:
  222               case HORIZONTAL:
  223                   break;
  224               default:
  225                   throw new IllegalArgumentException( "orientation must be one of: VERTICAL, HORIZONTAL" );
  226           }
  227       }
  228   
  229   
  230       /**
  231        * Returns a string representation of this <code>JSeparator</code>.
  232        * This method
  233        * is intended to be used only for debugging purposes, and the
  234        * content and format of the returned string may vary between
  235        * implementations. The returned string may be empty but may not
  236        * be <code>null</code>.
  237        *
  238        * @return  a string representation of this <code>JSeparator</code>
  239        */
  240       protected String paramString() {
  241           String orientationString = (orientation == HORIZONTAL ?
  242                                       "HORIZONTAL" : "VERTICAL");
  243   
  244           return super.paramString() +
  245           ",orientation=" + orientationString;
  246       }
  247   
  248   /////////////////
  249   // Accessibility support
  250   ////////////////
  251   
  252       /**
  253        * Gets the AccessibleContext associated with this JSeparator.
  254        * For separators, the AccessibleContext takes the form of an
  255        * AccessibleJSeparator.
  256        * A new AccessibleJSeparator instance is created if necessary.
  257        *
  258        * @return an AccessibleJSeparator that serves as the
  259        *         AccessibleContext of this JSeparator
  260        */
  261       public AccessibleContext getAccessibleContext() {
  262           if (accessibleContext == null) {
  263               accessibleContext = new AccessibleJSeparator();
  264           }
  265           return accessibleContext;
  266       }
  267   
  268       /**
  269        * This class implements accessibility support for the
  270        * <code>JSeparator</code> class.  It provides an implementation of the
  271        * Java Accessibility API appropriate to separator user-interface elements.
  272        * <p>
  273        * <strong>Warning:</strong>
  274        * Serialized objects of this class will not be compatible with
  275        * future Swing releases. The current serialization support is
  276        * appropriate for short term storage or RMI between applications running
  277        * the same version of Swing.  As of 1.4, support for long term storage
  278        * of all JavaBeans<sup><font size="-2">TM</font></sup>
  279        * has been added to the <code>java.beans</code> package.
  280        * Please see {@link java.beans.XMLEncoder}.
  281        */
  282       protected class AccessibleJSeparator extends AccessibleJComponent {
  283   
  284           /**
  285            * Get the role of this object.
  286            *
  287            * @return an instance of AccessibleRole describing the role of the
  288            * object
  289            */
  290           public AccessibleRole getAccessibleRole() {
  291               return AccessibleRole.SEPARATOR;
  292           }
  293       }
  294   }

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