1 /*
   2  * Copyright (c) 2019, 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 sun.awt;
  27 
  28 import java.awt.GraphicsEnvironment;
  29 import java.awt.Toolkit;
  30 import java.security.AccessController;
  31 import java.security.PrivilegedAction;
  32 
  33 public class PlatformGraphicsInfo {
  34 
  35     public static GraphicsEnvironment createGE() {
  36         return new X11GraphicsEnvironment();
  37     }
  38 
  39     public static Toolkit createToolkit() {
  40         return new sun.awt.X11.XToolkit();
  41     }
  42 
  43     /**
  44       * Called from java.awt.GraphicsEnvironment when
  45       * to check if on this platform, the JDK should default to
  46       * headless mode, in the case the application did specify
  47       * a value for the java.awt.headless system property.
  48       */
  49     public static boolean getDefaultHeadlessProperty() {
  50         return
  51             AccessController.doPrivileged((PrivilegedAction<Boolean>) () -> {
  52 
  53                final String display = System.getenv("DISPLAY");
  54                return  display == null || display.trim().isEmpty();
  55             });
  56     }
  57 
  58     /**
  59       * Called from java.awt.GraphicsEnvironment when
  60       * getDefaultHeadlessProperty() has returned true, and
  61       * the application has called an API that requires headful.
  62       */
  63     public static String getDefaultHeadlessMessage() {
  64         return
  65             "\nNo X11 DISPLAY variable was set,\n" +
  66             "but this program performed an operation which requires it.";
  67     }
  68 }