Source for javax.swing.JCheckBoxMenuItem

   1: /* JCheckBoxMenuItem.java --
   2:  Copyright (C) 2002, 2004, 2006, Free Software Foundation, Inc.
   3: 
   4:  This file is part of GNU Classpath.
   5: 
   6:  GNU Classpath is free software; you can redistribute it and/or modify
   7:  it under the terms of the GNU General Public License as published by
   8:  the Free Software Foundation; either version 2, or (at your option)
   9:  any later version.
  10: 
  11:  GNU Classpath is distributed in the hope that it will be useful, but
  12:  WITHOUT ANY WARRANTY; without even the implied warranty of
  13:  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14:  General Public License for more details.
  15: 
  16:  You should have received a copy of the GNU General Public License
  17:  along with GNU Classpath; see the file COPYING.  If not, write to the
  18:  Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  19:  02110-1301 USA.
  20: 
  21:  Linking this library statically or dynamically with other modules is
  22:  making a combined work based on this library.  Thus, the terms and
  23:  conditions of the GNU General Public License cover the whole
  24:  combination.
  25: 
  26:  As a special exception, the copyright holders of this library give you
  27:  permission to link this library with independent modules to produce an
  28:  executable, regardless of the license terms of these independent
  29:  modules, and to copy and distribute the resulting executable under
  30:  terms of your choice, provided that you also meet, for each linked
  31:  independent module, the terms and conditions of the license of that
  32:  module.  An independent module is a module which is not derived from
  33:  or based on this library.  If you modify this library, you may extend
  34:  this exception to your version of the library, but you are not
  35:  obligated to do so.  If you do not wish to do so, delete this
  36:  exception statement from your version. */
  37: 
  38: 
  39: package javax.swing;
  40: 
  41: import javax.accessibility.Accessible;
  42: import javax.accessibility.AccessibleContext;
  43: import javax.accessibility.AccessibleRole;
  44: 
  45: /**
  46:  * A menu item that displays a checkbox. Its behaviour is very similar to
  47:  * {@link JCheckBox}. Just like the <code>JCheckBox</code>, user can check
  48:  * and uncheck this menu item by clicking on it. Also
  49:  * {@link AbstractButton#setSelected} and {@link #setState} can be use used for
  50:  * the same purpose. <code>JCheckBoxMenuItem</code> uses
  51:  * <code>ToggleButtonModel</code> to keep track of its selection.
  52:  * 
  53:  * @author original author unknown
  54:  */
  55: public class JCheckBoxMenuItem
  56:     extends JMenuItem
  57:     implements SwingConstants, Accessible
  58: {
  59:   private static final long serialVersionUID = - 6676402307973384715L;
  60: 
  61:   /** name for the UI delegate for this menuItem. */
  62:   private static final String uiClassID = "CheckBoxMenuItemUI";
  63: 
  64:   /** Indicates whether this menu item is checked. */
  65:   private boolean state;
  66: 
  67:   /**
  68:    * This array contains text of this menu item if this menu item is in checked
  69:    * state and null it is not.
  70:    */
  71:   private Object[] selectedObjects = new Object[1];
  72: 
  73:   /**
  74:    * Creates a new JCheckBoxMenuItem object.
  75:    */
  76:   public JCheckBoxMenuItem()
  77:   {
  78:     this(null, null);
  79:   }
  80: 
  81:   /**
  82:    * Creates a new JCheckBoxMenuItem with given icon
  83:    * 
  84:    * @param icon Icon for this menu item
  85:    */
  86:   public JCheckBoxMenuItem(Icon icon)
  87:   {
  88:     this(null, icon);
  89:   }
  90: 
  91:   /**
  92:    * Creates a new JCheckBoxMenuItem with given label
  93:    * 
  94:    * @param text Label for this menu item
  95:    */
  96:   public JCheckBoxMenuItem(String text)
  97:   {
  98:     this(text, null);
  99:   }
 100: 
 101:   /**
 102:    * Creates a new JCheckBoxMenuItem using given action
 103:    * 
 104:    * @param action Action for this menu item.
 105:    */
 106:   public JCheckBoxMenuItem(Action action)
 107:   {
 108:     this();
 109:     setAction(action);
 110:   }
 111: 
 112:   /**
 113:    * Creates a new JCheckBoxMenuItem object with given label and icon
 114:    * 
 115:    * @param text Label for this menu item
 116:    * @param icon Icon for this menu item
 117:    */
 118:   public JCheckBoxMenuItem(String text, Icon icon)
 119:   {
 120:     this(text, icon, false);
 121:   }
 122: 
 123:   /**
 124:    * Creates a new JCheckBoxMenuItem object using specified label and marked as
 125:    * checked if given 'state' is true.
 126:    * 
 127:    * @param text Label for this menu item
 128:    * @param state <code>true</code> if this item should be in checked state
 129:    *          and <code>false</code> otherwise
 130:    */
 131:   public JCheckBoxMenuItem(String text, boolean state)
 132:   {
 133:     this(text, null, state);
 134:   }
 135: 
 136:   /**
 137:    * Creates a new JCheckBoxMenuItem object with given label, icon, and marked
 138:    * as checked if given 'state' is true.
 139:    * 
 140:    * @param text Label for this menu item
 141:    * @param icon icon for this menu item
 142:    * @param state <code>true</code> if this item should be in checked state
 143:    *          and false otherwise
 144:    */
 145:   public JCheckBoxMenuItem(String text, Icon icon, boolean state)
 146:   {
 147:     super(text, icon);
 148:     setModel(new JToggleButton.ToggleButtonModel());
 149:     this.state = state;
 150:     if (state == true)
 151:       this.setSelected(true);
 152:     setFocusable(false);
 153:   }
 154: 
 155:   /**
 156:    * This method returns a name to identify which look and feel class will be
 157:    * the UI delegate for the menuItem.
 158:    * 
 159:    * @return The Look and Feel classID. "JCheckBoxMenuItemUI"
 160:    */
 161:   public String getUIClassID()
 162:   {
 163:     return uiClassID;
 164:   }
 165: 
 166:   /**
 167:    * Returns checked state for this check box menu item.
 168:    * 
 169:    * @return Returns true if this menu item is in checked state and false
 170:    *         otherwise.
 171:    */
 172:   public boolean getState()
 173:   {
 174:     return state;
 175:   }
 176: 
 177:   /**
 178:    * Sets state for this check box menu item. If given 'state' is true, then
 179:    * mark menu item as checked, and uncheck this menu item otherwise.
 180:    * 
 181:    * @param state new state for this menu item
 182:    */
 183:   public synchronized void setState(boolean state)
 184:   {
 185:     this.state = state;
 186:   }
 187: 
 188:   /**
 189:    * This method returns array containing label of this menu item if it is
 190:    * selected and null otherwise.
 191:    * 
 192:    * @return Array containing label of this menu item if this menu item is
 193:    *         selected or null otherwise.
 194:    */
 195:   public Object[] getSelectedObjects()
 196:   {
 197:     if (state == true)
 198:       selectedObjects[0] = this.getText();
 199:     else
 200:       selectedObjects[0] = null;
 201: 
 202:     return selectedObjects;
 203:   }
 204: 
 205:   /**
 206:    * This method overrides JComponent.requestFocus with an empty implementation,
 207:    * since JCheckBoxMenuItems should not receive focus in general.
 208:    */
 209:   public void requestFocus()
 210:   {
 211:     // Should do nothing here
 212:   }
 213: 
 214:   /**
 215:    * Returns a string describing the attributes for the
 216:    * <code>JCheckBoxMenuItem</code> component, for use in debugging. The
 217:    * return value is guaranteed to be non-<code>null</code>, but the format
 218:    * of the string may vary between implementations.
 219:    * 
 220:    * @return A string describing the attributes of the
 221:    *         <code>JCheckBoxMenuItem</code>.
 222:    */
 223:   protected String paramString()
 224:   {
 225:     // calling super seems to be sufficient to match the reference
 226:     // implementation here...
 227:     return super.paramString();
 228:   }
 229: 
 230:   /**
 231:    * Returns the object that provides accessibility features for this
 232:    * <code>JCheckBoxMenuItem</code> component.
 233:    * 
 234:    * @return The accessible context (an instance of
 235:    *         {@link AccessibleJCheckBoxMenuItem}).
 236:    */
 237:   public AccessibleContext getAccessibleContext()
 238:   {
 239:     if (accessibleContext == null)
 240:       accessibleContext = new AccessibleJCheckBoxMenuItem();
 241: 
 242:     return accessibleContext;
 243:   }
 244: 
 245:   /**
 246:    * Provides the accessibility features for the <code>JCheckBoxMenuItem</code>
 247:    * component.
 248:    * 
 249:    * @see JCheckBoxMenuItem#getAccessibleContext()
 250:    */
 251:   protected class AccessibleJCheckBoxMenuItem
 252:       extends AccessibleJMenuItem
 253:   {
 254:     private static final long serialVersionUID = 1079958073579370777L;
 255: 
 256:     /**
 257:      * Creates a new <code>AccessibleJCheckBoxMenuItem</code> instance.
 258:      */
 259:     protected AccessibleJCheckBoxMenuItem()
 260:     {
 261:       // Nothing to do here.
 262:     }
 263: 
 264:     /**
 265:      * Returns the accessible role for the <code>JCheckBoxMenuItem</code>
 266:      * component.
 267:      * 
 268:      * @return {@link AccessibleRole#CHECK_BOX}.
 269:      */
 270:     public AccessibleRole getAccessibleRole()
 271:     {
 272:       return AccessibleRole.CHECK_BOX;
 273:     }
 274:   }
 275: }