/*
 * Copyright 1997-2004 Sun Microsystems, Inc.  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.  Sun designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
 * CA 95054 USA or visit www.sun.com if you need additional information or
 * have any questions.
 */

package java.beans.beancontext;

import java.util.EventObject;

import java.beans.beancontext.BeanContext;
import java.beans.beancontext.BeanContextEvent;

import java.util.Arrays;
import java.util.Collection;
import java.util.Iterator;

/**
 * A <code>BeanContextMembershipEvent</code> encapsulates
 * the list of children added to, or removed from,
 * the membership of a particular <code>BeanContext</code>.
 * An instance of this event is fired whenever a successful
 * add(), remove(), retainAll(), removeAll(), or clear() is
 * invoked on a given <code>BeanContext</code> instance.
 * Objects interested in receiving events of this type must
 * implement the <code>BeanContextMembershipListener</code>
 * interface, and must register their intent via the
 * <code>BeanContext</code>'s
 * <code>addBeanContextMembershipListener(BeanContextMembershipListener bcml)
 * </code> method.
 *
 * @author      Laurence P. G. Cable
 * @since       1.2
 * @see         java.beans.beancontext.BeanContext
 * @see         java.beans.beancontext.BeanContextEvent
 * @see         java.beans.beancontext.BeanContextMembershipListener
 */
public class BeanContextMembershipEvent extends BeanContextEvent {

    /**
     * Contruct a BeanContextMembershipEvent
     *
     * @param bc        The BeanContext source
     * @param changes   The Children affected
     * @throws NullPointerException if <CODE>changes</CODE> is <CODE>null</CODE>
     */

    public BeanContextMembershipEvent(BeanContext bc, Collection changes) {
        super(bc);

        if (changes == null) throw new NullPointerException(
            "BeanContextMembershipEvent constructor:  changes is null.");

        children = changes;
    }

    /**
     * Contruct a BeanContextMembershipEvent
     *
     * @param bc        The BeanContext source
     * @param changes   The Children effected
     * @exception       NullPointerException if changes associated with this
     *                  event are null.
     */

    public BeanContextMembershipEvent(BeanContext bc, Object[] changes) {
        super(bc);

        if (changes == null) throw new NullPointerException(
            "BeanContextMembershipEvent:  changes is null.");

        children = Arrays.asList(changes);
    }

    /**
     * Gets the number of children affected by the notification.
     * @return the number of children affected by the notification
     */
    public int size() { return children.size(); }

    /**
     * Is the child specified affected by the event?
     * @return <code>true</code> if affected, <code>false</code>
     * if not
     */
    public boolean contains(Object child) {
        return children.contains(child);
    }

    /**
     * Gets the array of children affected by this event.
     * @return the array of children affected
     */
    public Object[] toArray() { return children.toArray(); }

    /**
     * Gets the array of children affected by this event.
     * @return the array of children effected
     */
    public Iterator iterator() { return children.iterator(); }

    /*
     * fields
     */

   /**
    * The list of children affected by this
    * event notification.
    */
    protected Collection children;
}