libjava/javax/accessibility/AccessibleValue.java

   1 /* AccessibleValue.java -- aids in accessibly controlling values
   2    Copyright (C) 2002, 2005  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., 59 Temple Place, Suite 330, Boston, MA
  19 02111-1307 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.accessibility;
  40
  41 /**
  42  * If an object implements this interface then it must be able to control
  43  * a numerical value. For example, a scroll bar has a position represented
  44  * by a number. Accessibility software can use the implementations of this
  45  * interface to change the associated value.
  46  *
  47  * <p>The <code>AccessibleContext.getAccessibleValue()</code> method should
  48  * return <code>null</code> if an object does not implement this interface.
  49  *
  50  * @author Eric Blake (ebb9@email.byu.edu)
  51  * @see Accessible
  52  * @see AccessibleContext
  53  * @see AccessibleContext#getAccessibleValue()
  54  * @since 1.2
  55  * @status updated to 1.4
  56  */
  57 public interface AccessibleValue
  58 {
  59   /**
  60    * Gets the current value of this object, or null if it has not been set.
  61    *
  62    * @return the current value, or null
  63    * @see #setCurrentAccessibleValue(Number)
  64    */
  65   Number getCurrentAccessibleValue();
  66
  67   /**
  68    * Sets the current value of this object. Returns true if the number
  69    * successfully changed.
  70    *
  71    * @param number the new value
  72    * @return true on success
  73    */
  74   // XXX What happens if number is null?
  75   boolean setCurrentAccessibleValue(Number number);
  76
  77   /**
  78    * Gets the minimum value in the range of this object, or null if there is
  79    * no minimum.
  80    *
  81    * @return the minimum
  82    * @see #getMaximumAccessibleValue()
  83    */
  84   Number getMinimumAccessibleValue();
  85
  86   /**
  87    * Gets the maximum value in the range of this object, or null if there is
  88    * no maximum.
  89    *
  90    * @return the maximum
  91    * @see #getMinimumAccessibleValue()
  92    */
  93   Number getMaximumAccessibleValue();
  94 } // interface AccessibleValue