/*
 * @(#)AccessibleRelation.java	1.6 00/02/02
 *
 * Copyright 1999, 2000 Sun Microsystems, Inc. All Rights Reserved.
 * 
 * This software is the proprietary information of Sun Microsystems, Inc.  
 * Use is subject to license terms.
 * 
 */

package javax.accessibility;

import java.util.Vector;
import java.util.Locale;
import java.util.MissingResourceException;
import java.util.ResourceBundle;

/**
 * <P>Class AccessibleRelation describes a relation between the
 * object that implements the AccessibleRelation and one or more other
 * objects.  The actual relations that an object has with other
 * objects are defined as an AccessibleRelationSet, which is a composed
 * set of AccessibleRelations.
 * <p>The toDisplayString method allows you to obtain the localized string 
 * for a locale independent key from a predefined ResourceBundle for the 
 * keys defined in this class.
 * <p>The constants in this class present a strongly typed enumeration
 * of common object roles.  A public constructor for this class has been
 * purposely omitted and applications should use one of the constants
 * from this class.  If the constants in this class are not sufficient
 * to describe the role of an object, a subclass should be generated
 * from this class and it should provide constants in a similar manner.
 *
 * @version     1.6 @(#)AccessibleRelation.java	1.6
 * @author      Lynn Monsanto
 */
public class AccessibleRelation extends AccessibleBundle {

    /*
     * The group of objects that participate in the relation.
     * The relation may be one-to-one or one-to-many.  For
     * example, in the case of a LABEL_FOR relation, the target
     * vector would contain a list of objects labeled by the object
     * that implements this AccessibleRelation.  In the case of a 
     * MEMBER_OF relation, the target vector would contain all 
     * of the components that are members of the same group as the
     * object that implements this AccessibleRelation.
     */
    private Object [] target = new Object[0];                                

    /**
     * Indicates an object is a label for one or more target objects.
     * 
     * @see #getTarget
     * @see #CONTROLLER_FOR
     * @see #CONTROLLED_BY
     * @see #LABELED_BY
     * @see #MEMBER_OF
     */
    public static final String LABEL_FOR = new String("labelFor");

    /**
     * Indicates an object is labeled by one or more target objects.
     * 
     * @see #getTarget
     * @see #CONTROLLER_FOR
     * @see #CONTROLLED_BY
     * @see #LABEL_FOR
     * @see #MEMBER_OF
     */
    public static final String LABELED_BY = new String("labeledBy");

    /**
     * Indicates an object is a member of a group of one or more
     * target objects.
     * 
     * @see #getTarget
     * @see #CONTROLLER_FOR
     * @see #CONTROLLED_BY
     * @see #LABEL_FOR
     * @see #LABELED_BY
     */
    public static final String MEMBER_OF = new String("memberOf");

    /**
     * Indicates an object is a controller for one or more target
     * objects.
     * 
     * @see #getTarget
     * @see #CONTROLLED_BY
     * @see #LABEL_FOR
     * @see #LABELED_BY
     * @see #MEMBER_OF
     */
    public static final String CONTROLLER_FOR = new String("controllerFor");

    /**
     * Indicates an object is controlled by one or more target
     * objects.
     * 
     * @see #getTarget
     * @see #CONTROLLER_FOR
     * @see #LABEL_FOR
     * @see #LABELED_BY
     * @see #MEMBER_OF
     */
    public static final String CONTROLLED_BY = new String("controlledBy");

    /** 
     * Identifies that the target group for a label has changed
     */
    public static final String LABEL_FOR_PROPERTY = "labelForProperty";

    /** 
     * Identifies that the objects that are doing the labeling have changed
     */
    public static final String LABELED_BY_PROPERTY = "labeledByProperty";

    /** 
     * Identifies that group membership has changed. 
     */
    public static final String MEMBER_OF_PROPERTY = "memberOfProperty";

    /** 
     * Identifies that the controller for the target object has changed
     */
    public static final String CONTROLLER_FOR_PROPERTY = "controllerForProperty";

    /** 
     * Identifies that the target object that is doing the controlling has
     * changed
     */
    public static final String CONTROLLED_BY_PROPERTY = "controlledByProperty";

    /**
     * Create a new AccessibleRelation using the given locale independent key.
     * @param key the locale independent name of the relation.
     * @note The String should be a locale independent key for the relation.
     * It is not intended to be used as the actual String to display 
     * to the user.  To get the localized string, use toDisplayString.
     * @see AccessibleBundle#toDisplayString
     */
    public AccessibleRelation(String key) {
        this.key = key;
	this.target = null;
    }

    /**
     * Creates a new AccessibleRelation using the given locale independent key.
     * @param key the locale independent name of the relation.
     * @note The String should be a locale independent key for the relation.
     * It is not intended to be used as the actual String to display 
     * to the user.  To get the localized string, use toDisplayString.
     * @param target the target object for this relation
     * @see AccessibleBundle#toDisplayString
     */
    public AccessibleRelation(String key, Object target) {
        this.key = key;
	this.target = new Object[1];
	this.target[0] = target;
    }

    /**
     * Creates a new AccessibleRelation using the given locale independent key.
     * @param key the locale independent name of the relation.
     * @note The String should be a locale independent key for the relation.
     * It is not intended to be used as the actual String to display 
     * to the user.  To get the localized string, use toDisplayString.
     * @param target the target object(s) for this relation
     * @see AccessibleBundle#toDisplayString
     */
    public AccessibleRelation(String key, Object [] target) {
        this.key = key;
	this.target = target;
    }

    /**
     * Returns the key for this relation
     *
     * @return the key for this relation
     * 
     * @see #CONTROLLER_FOR
     * @see #CONTROLLED_BY
     * @see #LABEL_FOR
     * @see #LABELED_BY
     * @see #MEMBER_OF
     */
    public String getKey() {
	return this.key;
    }

    /**
     * Returns the target objects for this relation
     *
     * @return an array containing the target objects for this relation
     */
    public Object [] getTarget() {
        if (target == null) {
	    target = new Object[0];
	}
	Object [] retval = new Object[target.length];
	for (int i = 0; i < target.length; i++) {
	    retval[i] = target[i];
	}
	return retval;
    }

    /**
     * Sets the target object for this relation
     *
     * @param target the target object for this relation
     */
    public void setTarget(Object target) {
	this.target = new Object[1];
	this.target[0] = target;
    }

    /**
     * Sets the target objects for this relation
     *
     * @param target an array containing the target objects for this relation
     */
    public void setTarget(Object [] target) {
	this.target = target;
    }
}