1 /*
   2  * Copyright (c) 2016, 2018, 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.awt.desktop;
  27 
  28 import java.awt.Desktop;
  29 import java.awt.GraphicsEnvironment;
  30 import java.awt.HeadlessException;
  31 
  32 /**
  33  * Event sent when the user session has been changed.
  34  *
  35  * Some systems may provide a reason of a user session change.
  36  *
  37  * @see UserSessionListener#userSessionActivated(UserSessionEvent)
  38  * @see UserSessionListener#userSessionDeactivated(UserSessionEvent)
  39  *
  40  * @since 9
  41  */
  42 public final class UserSessionEvent extends AppEvent {
  43 
  44     private static final long serialVersionUID = 6747138462796569055L;
  45 
  46     private final Reason reason;
  47 
  48     /**
  49      * Kinds of available reasons of user session change.
  50      */
  51     public static enum Reason {
  52         /**
  53          * The system does not provide a reason for a session change.
  54          */
  55         UNSPECIFIED,
  56 
  57         /**
  58          * The session was connected/disconnected to the console terminal.
  59          */
  60         CONSOLE,
  61 
  62         /**
  63          * The session was connected/disconnected to the remote terminal.
  64          */
  65         REMOTE,
  66 
  67         /**
  68          * The session has been locked/unlocked.
  69          */
  70         LOCK
  71     }
  72 
  73     /**
  74      * Constructs a {@code UserSessionEvent}.
  75      *
  76      * @param  reason the reason of the user session change
  77      * @throws HeadlessException if {@link GraphicsEnvironment#isHeadless()}
  78      *         returns {@code true}
  79      * @throws UnsupportedOperationException if Desktop API is not supported on
  80      *         the current platform
  81      * @see Desktop#isDesktopSupported()
  82      * @see java.awt.GraphicsEnvironment#isHeadless
  83      */
  84     public UserSessionEvent(Reason reason) {
  85         this.reason = reason;
  86     }
  87 
  88     /**
  89      * Gets a reason of the user session change.
  90      *
  91      * @return reason a reason
  92      * @see Reason#UNSPECIFIED
  93      * @see Reason#CONSOLE
  94      * @see Reason#REMOTE
  95      * @see Reason#LOCK
  96      */
  97     public Reason getReason() {
  98         return reason;
  99     }
 100 }