001 /* AccessibleValue.java -- aids in accessibly controlling values 002 Copyright (C) 2002, 2005 Free Software Foundation, Inc. 003 004 This file is part of GNU Classpath. 005 006 GNU Classpath is free software; you can redistribute it and/or modify 007 it under the terms of the GNU General Public License as published by 008 the Free Software Foundation; either version 2, or (at your option) 009 any later version. 010 011 GNU Classpath is distributed in the hope that it will be useful, but 012 WITHOUT ANY WARRANTY; without even the implied warranty of 013 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 014 General Public License for more details. 015 016 You should have received a copy of the GNU General Public License 017 along with GNU Classpath; see the file COPYING. If not, write to the 018 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 019 02110-1301 USA. 020 021 Linking this library statically or dynamically with other modules is 022 making a combined work based on this library. Thus, the terms and 023 conditions of the GNU General Public License cover the whole 024 combination. 025 026 As a special exception, the copyright holders of this library give you 027 permission to link this library with independent modules to produce an 028 executable, regardless of the license terms of these independent 029 modules, and to copy and distribute the resulting executable under 030 terms of your choice, provided that you also meet, for each linked 031 independent module, the terms and conditions of the license of that 032 module. An independent module is a module which is not derived from 033 or based on this library. If you modify this library, you may extend 034 this exception to your version of the library, but you are not 035 obligated to do so. If you do not wish to do so, delete this 036 exception statement from your version. */ 037 038 039 package javax.accessibility; 040 041 /** 042 * If an object implements this interface then it must be able to control 043 * a numerical value. For example, a scroll bar has a position represented 044 * by a number. Accessibility software can use the implementations of this 045 * interface to change the associated value. 046 * 047 * <p>The <code>AccessibleContext.getAccessibleValue()</code> method should 048 * return <code>null</code> if an object does not implement this interface. 049 * 050 * @author Eric Blake (ebb9@email.byu.edu) 051 * @see Accessible 052 * @see AccessibleContext 053 * @see AccessibleContext#getAccessibleValue() 054 * @since 1.2 055 * @status updated to 1.4 056 */ 057 public interface AccessibleValue 058 { 059 /** 060 * Gets the current value of this object, or null if it has not been set. 061 * 062 * @return the current value, or null 063 * @see #setCurrentAccessibleValue(Number) 064 */ 065 Number getCurrentAccessibleValue(); 066 067 /** 068 * Sets the current value of this object. Returns true if the number 069 * successfully changed. 070 * 071 * @param number the new value 072 * @return true on success 073 */ 074 // XXX What happens if number is null? 075 boolean setCurrentAccessibleValue(Number number); 076 077 /** 078 * Gets the minimum value in the range of this object, or null if there is 079 * no minimum. 080 * 081 * @return the minimum 082 * @see #getMaximumAccessibleValue() 083 */ 084 Number getMinimumAccessibleValue(); 085 086 /** 087 * Gets the maximum value in the range of this object, or null if there is 088 * no maximum. 089 * 090 * @return the maximum 091 * @see #getMinimumAccessibleValue() 092 */ 093 Number getMaximumAccessibleValue(); 094 } // interface AccessibleValue