1 /*
   2  * Copyright (c) 1997, 2005, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package java.rmi.activation;
  27 
  28 import java.rmi.MarshalledObject;
  29 import java.rmi.Remote;
  30 import java.rmi.RemoteException;
  31 import java.rmi.activation.UnknownGroupException;
  32 import java.rmi.activation.UnknownObjectException;
  33 
  34 /**
  35  * An <code>ActivationMonitor</code> is specific to an
  36  * <code>ActivationGroup</code> and is obtained when a group is
  37  * reported active via a call to
  38  * <code>ActivationSystem.activeGroup</code> (this is done
  39  * internally). An activation group is responsible for informing its
  40  * <code>ActivationMonitor</code> when either: its objects become active or
  41  * inactive, or the group as a whole becomes inactive.
  42  *
  43  * @author      Ann Wollrath
  44  * @see         Activator
  45  * @see         ActivationSystem
  46  * @see         ActivationGroup
  47  * @since       1.2
  48  */
  49 public interface ActivationMonitor extends Remote {
  50 
  51    /**
  52      * An activation group calls its monitor's
  53      * <code>inactiveObject</code> method when an object in its group
  54      * becomes inactive (deactivates).  An activation group discovers
  55      * that an object (that it participated in activating) in its VM
  56      * is no longer active, via calls to the activation group's
  57      * <code>inactiveObject</code> method. <p>
  58      *
  59      * The <code>inactiveObject</code> call informs the
  60      * <code>ActivationMonitor</code> that the remote object reference
  61      * it holds for the object with the activation identifier,
  62      * <code>id</code>, is no longer valid. The monitor considers the
  63      * reference associated with <code>id</code> as a stale reference.
  64      * Since the reference is considered stale, a subsequent
  65      * <code>activate</code> call for the same activation identifier
  66      * results in re-activating the remote object.<p>
  67      *
  68      * @param id the object's activation identifier
  69      * @exception UnknownObjectException if object is unknown
  70      * @exception RemoteException if remote call fails
  71      * @since 1.2
  72      */
  73     public void inactiveObject(ActivationID id)
  74         throws UnknownObjectException, RemoteException;
  75 
  76     /**
  77      * Informs that an object is now active. An <code>ActivationGroup</code>
  78      * informs its monitor if an object in its group becomes active by
  79      * other means than being activated directly (i.e., the object
  80      * is registered and "activated" itself).
  81      *
  82      * @param id the active object's id
  83      * @param obj the marshalled form of the object's stub
  84      * @exception UnknownObjectException if object is unknown
  85      * @exception RemoteException if remote call fails
  86      * @since 1.2
  87      */
  88     public void activeObject(ActivationID id,
  89                              MarshalledObject<? extends Remote> obj)
  90         throws UnknownObjectException, RemoteException;
  91 
  92     /**
  93      * Informs that the group is now inactive. The group will be
  94      * recreated upon a subsequent request to activate an object
  95      * within the group. A group becomes inactive when all objects
  96      * in the group report that they are inactive.
  97      *
  98      * @param id the group's id
  99      * @param incarnation the group's incarnation number
 100      * @exception UnknownGroupException if group is unknown
 101      * @exception RemoteException if remote call fails
 102      * @since 1.2
 103      */
 104     public void inactiveGroup(ActivationGroupID id,
 105                               long incarnation)
 106         throws UnknownGroupException, RemoteException;
 107 
 108 }