Supporting preventing system sleep for desktop

forge-gui-desktop/src/main/java/forge/GuiDesktop.java

@@ -49,6 +49,7 @@ import forge.toolbox.FSkin.SkinImage;
 import forge.util.BuildInfo;
 import forge.util.Callback;
 import forge.util.FileUtil;
+import forge.util.OperatingSystem;
 
 public class GuiDesktop implements IGuiBase {
     @Override
@@ -286,6 +287,6 @@ public class GuiDesktop implements IGuiBase {
 
     @Override
     public void preventSystemSleep(boolean preventSleep) {
-        
+        OperatingSystem.preventSystemSleep(preventSleep);
     }
 }

forge-gui-mobile-dev/src/forge/app/Main.java

@@ -12,6 +12,7 @@ import forge.Forge;
 import forge.assets.AssetsDownloader;
 import forge.interfaces.IDeviceAdapter;
 import forge.util.FileUtil;
+import forge.util.OperatingSystem;
 import forge.util.RestartUtil;
 import forge.util.Utils;
 
@@ -96,7 +97,7 @@ public class Main {
 
         @Override
         public void preventSystemSleep(boolean preventSleep) {
-            
+            OperatingSystem.preventSystemSleep(preventSleep);
         }
     }
 }

forge-gui/src/main/java/forge/util/OperatingSystem.java

@@ -1,5 +1,7 @@
 package forge.util;
 
+import forge.FThreads;
+
 public class OperatingSystem {
     private static String os = System.getProperty("os.name").toLowerCase();
 
@@ -18,4 +20,42 @@ public class OperatingSystem {
     public static boolean isSolaris() {
         return os.contains("sunos");
     }
+
+    //utility for preventing system from sleeping
+    private static boolean preventSleep;
+    private static java.util.concurrent.ScheduledFuture<?> delayedKeepAwakeTask;
+
+    public static void preventSystemSleep(boolean preventSleep0) {
+        if (preventSleep == preventSleep0) { return; }
+        preventSleep = preventSleep0;
+
+        if (delayedKeepAwakeTask != null) { //ensure current delayed task canceled if needed
+            delayedKeepAwakeTask.cancel(false);
+            delayedKeepAwakeTask = null;
+        }
+
+        if (preventSleep) { //ensure task scheduled from EDT thread
+            FThreads.invokeInEdtNowOrLater(keepSystemAwake);
+        }
+    }
+
+    private static Runnable keepSystemAwake = new Runnable() {
+        @Override
+        public void run() {
+            if (!preventSleep) { return; } //ensure this flag is still set
+
+            try {
+                //use robot to simulate user action so system standby timer resets
+                java.awt.Robot robot = new java.awt.Robot();
+                robot.keyPress(0xF002); //simulate F15 key press since that won't do anything noticable
+
+                delayedKeepAwakeTask = ThreadUtil.delay(30000, keepSystemAwake); //repeat every 30 seconds until flag cleared
+            }
+            catch (Exception e) {
+                preventSleep = false;
+                delayedKeepAwakeTask = null;
+                e.printStackTrace();
+            }
+        }
+    };
 }