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. Some systems may provide a
  34  * reason of a user session change.
  35  *
  36  * @see UserSessionListener#userSessionActivated(UserSessionEvent)
  37  * @see UserSessionListener#userSessionDeactivated(UserSessionEvent)
  38  * @since 9
  39  */
  40 public final class UserSessionEvent extends AppEvent {
  41 
  42     /**
  43      * Use serialVersionUID from JDK 9 for interoperability.
  44      */
  45     private static final long serialVersionUID = 6747138462796569055L;
  46 
  47     /**
  48      * The reason of the user session change.
  49      */
  50     private final Reason reason;
  51 
  52     /**
  53      * Kinds of available reasons of user session change.
  54      */
  55     public static enum Reason {
  56         /**
  57          * The system does not provide a reason for a session change.
  58          */
  59         UNSPECIFIED,
  60 
  61         /**
  62          * The session was connected/disconnected to the console terminal.
  63          */
  64         CONSOLE,
  65 
  66         /**
  67          * The session was connected/disconnected to the remote terminal.
  68          */
  69         REMOTE,
  70 
  71         /**
  72          * The session has been locked/unlocked.
  73          */
  74         LOCK
  75     }
  76 
  77     /**
  78      * Constructs a {@code UserSessionEvent}.
  79      *
  80      * @param  reason the reason of the user session change
  81      * @throws HeadlessException if {@link GraphicsEnvironment#isHeadless()}
  82      *         returns {@code true}
  83      * @throws UnsupportedOperationException if Desktop API is not supported on
  84      *         the current platform
  85      * @see Desktop#isDesktopSupported()
  86      * @see java.awt.GraphicsEnvironment#isHeadless
  87      */
  88     public UserSessionEvent(Reason reason) {
  89         this.reason = reason;
  90     }
  91 
  92     /**
  93      * Gets a reason of the user session change.
  94      *
  95      * @return reason a reason
  96      * @see Reason#UNSPECIFIED
  97      * @see Reason#CONSOLE
  98      * @see Reason#REMOTE
  99      * @see Reason#LOCK
 100      */
 101     public Reason getReason() {
 102         return reason;
 103     }
 104 }