/*

 * Copyright (c) 1997, 2005, 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 java.rmi.activation;

import java.rmi.MarshalledObject;

import java.rmi.Remote;

import java.rmi.RemoteException;

import java.rmi.activation.UnknownGroupException;

import java.rmi.activation.UnknownObjectException;

/**

 * An <code>ActivationMonitor</code> is specific to an

 * <code>ActivationGroup</code> and is obtained when a group is

 * reported active via a call to

 * <code>ActivationSystem.activeGroup</code> (this is done

 * internally). An activation group is responsible for informing its

 * <code>ActivationMonitor</code> when either: its objects become active or

 * inactive, or the group as a whole becomes inactive.

 *

 * @author      Ann Wollrath

 * @see         Activator

 * @see         ActivationSystem

 * @see         ActivationGroup

 * @since       1.2

 */

public interface ActivationMonitor extends Remote {

   /**

     * An activation group calls its monitor's

     * <code>inactiveObject</code> method when an object in its group

     * becomes inactive (deactivates).  An activation group discovers

     * that an object (that it participated in activating) in its VM

     * is no longer active, via calls to the activation group's

     * <code>inactiveObject</code> method. <p>

     *

     * The <code>inactiveObject</code> call informs the

     * <code>ActivationMonitor</code> that the remote object reference

     * it holds for the object with the activation identifier,

     * <code>id</code>, is no longer valid. The monitor considers the

     * reference associated with <code>id</code> as a stale reference.

     * Since the reference is considered stale, a subsequent

     * <code>activate</code> call for the same activation identifier

     * results in re-activating the remote object.<p>

     *

     * @param id the object's activation identifier

     * @exception UnknownObjectException if object is unknown

     * @exception RemoteException if remote call fails

     * @since 1.2

     */

    public void inactiveObject(ActivationID id)

        throws UnknownObjectException, RemoteException;

    /**

     * Informs that an object is now active. An <code>ActivationGroup</code>

     * informs its monitor if an object in its group becomes active by

     * other means than being activated directly (i.e., the object

     * is registered and "activated" itself).

     *

     * @param id the active object's id

     * @param obj the marshalled form of the object's stub

     * @exception UnknownObjectException if object is unknown

     * @exception RemoteException if remote call fails

     * @since 1.2

     */

    public void activeObject(ActivationID id,

                             MarshalledObject<? extends Remote> obj)

        throws UnknownObjectException, RemoteException;

    /**

     * Informs that the group is now inactive. The group will be

     * recreated upon a subsequent request to activate an object

     * within the group. A group becomes inactive when all objects

     * in the group report that they are inactive.

     *

     * @param id the group's id

     * @param incarnation the group's incarnation number

     * @exception UnknownGroupException if group is unknown

     * @exception RemoteException if remote call fails

     * @since 1.2

     */

    public void inactiveGroup(ActivationGroupID id,

                              long incarnation)

        throws UnknownGroupException, RemoteException;

}