jdk/src/java.desktop/share/classes/javax/accessibility/AccessibleValue.java

/*
 * Copyright (c) 1997, 2017, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

package javax.accessibility;

/**
 * The {@code AccessibleValue} interface should be supported by any object that
 * supports a numerical value (e.g., a scroll bar). This interface provides the
 * standard mechanism for an assistive technology to determine and set the
 * numerical value as well as get the minimum and maximum values. Applications
 * can determine if an object supports the {@code AccessibleValue} interface by
 * first obtaining its {@code AccessibleContext} (see {@link Accessible}) and
 * then calling the {@link AccessibleContext#getAccessibleValue} method. If the
 * return value is not {@code null}, the object supports this interface.
 *
 * @author Peter Korn
 * @author Hans Muller
 * @author Willie Walker
 * @see Accessible
 * @see Accessible#getAccessibleContext
 * @see AccessibleContext
 * @see AccessibleContext#getAccessibleValue
 */
public interface AccessibleValue {

    /**
     * Get the value of this object as a {@code Number}. If the value has not
     * been set, the return value will be {@code null}.
     *
     * @return value of the object
     * @see #setCurrentAccessibleValue
     */
    public Number getCurrentAccessibleValue();

    /**
     * Set the value of this object as a {@code Number}.
     *
     * @param  n the number to use for the value
     * @return {@code true} if the value was set; else {@code false}
     * @see #getCurrentAccessibleValue
     */
    public boolean setCurrentAccessibleValue(Number n);

    // /**
    // * Get the description of the value of this object.
    // *
    // * @return description of the value of the object
    // */
    // public String getAccessibleValueDescription();

    /**
     * Get the minimum value of this object as a {@code Number}.
     *
     * @return minimum value of the object; {@code null} if this object does not
     *         have a minimum value
     * @see #getMaximumAccessibleValue
     */
    public Number getMinimumAccessibleValue();

    /**
     * Get the maximum value of this object as a {@code Number}.
     *
     * @return maximum value of the object; {@code null} if this object does not
     *         have a maximum value
     * @see #getMinimumAccessibleValue
     */
    public Number getMaximumAccessibleValue();
}