use an executor instead

src/main/java/edu/jhuapl/trinity/App.java

@@ -476,7 +476,7 @@ public void start(Stage stage) throws IOException {
         if(enableHttp) {
             reh.startHttpService();
         }
-        
+
         setupMissionTimer(scene);
         //add helper tools and overlays
         circleSpinner = new CircleProgressIndicator();

src/main/java/edu/jhuapl/trinity/javafx/handlers/RestEventHandler.java

@@ -25,58 +25,76 @@
 import edu.jhuapl.trinity.messages.TrinityHttpServer;
 import javafx.application.Platform;
 import javafx.event.EventHandler;
+import javafx.scene.Scene;
 import javafx.scene.paint.Color;
 import javafx.scene.text.Font;
 
-import javafx.scene.Scene;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.Future;
+import java.util.logging.Logger;
 
 /**
  * @author Sean Phillips
  */
 public class RestEventHandler implements EventHandler<RestEvent> {
-    Scene scene;
-    TrinityHttpServer trinityHttpServer = null;
-    Thread serverThread = null;
-
+
+    private static final Logger LOGGER = Logger.getLogger(RestEventHandler.class.getName());
+
+    private final Scene scene;
+    private ExecutorService executor;
+    private Future<?> serverFuture;
+
+
     public RestEventHandler(Scene scene) {
         this.scene = scene;
+        this.executor = Executors.newSingleThreadExecutor();
     }
-    
+
     public void startHttpService() {
-        if(null == trinityHttpServer && null == serverThread) {
-            System.out.println("Creating Trinity HTTP Server...");
-            trinityHttpServer = new TrinityHttpServer(scene);
-            serverThread = new Thread(trinityHttpServer, "Trinity HTTP Server");
-            serverThread.setDaemon(true);
-            serverThread.start();        
-            Platform.runLater(() -> {
-                scene.getRoot().fireEvent(
-                    new CommandTerminalEvent("Creating Trinity HTTP Server...",
-                        new Font("Consolas", 20), Color.GREEN));
-            });
+        if (serverFuture != null && !serverFuture.isDone()) {
+            LOGGER.warning("Trinity HTTP Server is already running.");
+            return;
         }
+
+        LOGGER.info("Creating Trinity HTTP Server...");
+        serverFuture = executor.submit(new TrinityHttpServer(scene));
+
+        Platform.runLater(() -> {
+            scene.getRoot().fireEvent(
+                new CommandTerminalEvent("Creating Trinity HTTP Server...",
+                    new Font("Consolas", 20), Color.GREEN));
+        });
     }
+
     public void stopHttpService() {
-        if(null != trinityHttpServer && null != serverThread) {
-            Platform.runLater(() -> {
-                scene.getRoot().fireEvent(
-                    new CommandTerminalEvent("Stopping Trinity HTTP Server...",
-                        new Font("Consolas", 20), Color.YELLOW));
-            });
-            trinityHttpServer.stop(); //will kill future inside the runnable.
-            trinityHttpServer = null;
-            serverThread = null;
+        if (serverFuture == null || serverFuture.isDone()) {
+            LOGGER.warning("Trinity HTTP Server is not running.");
+            return;
         }
+        Platform.runLater(() -> {
+            scene.getRoot().fireEvent(
+                new CommandTerminalEvent("Stopping Trinity HTTP Server...",
+                    new Font("Consolas", 20), Color.YELLOW));
+        });
+
+        // Cancel the running task and interrupt if running
+        serverFuture.cancel(true);
+        // Disable new tasks from being submitted
+        executor.shutdown();
+        // Cancel currently executing tasks (if any)
+        executor.shutdownNow();
+
+        // Reset the executor service for future use
+        executor = Executors.newSingleThreadExecutor();
     }
 
     @Override
     public void handle(RestEvent t) {
-        if(t.getEventType() == RestEvent.START_RESTSERVER_THREAD) {
-            if(null == trinityHttpServer && null == serverThread)
-                startHttpService();
-        } else if(t.getEventType() == RestEvent.TERMINATE_RESTSERVER_THREAD) {
-            if(null != trinityHttpServer && null != serverThread)
-                stopHttpService();
+        if (t.getEventType() == RestEvent.START_RESTSERVER_THREAD) {
+            startHttpService();
+        } else if (t.getEventType() == RestEvent.TERMINATE_RESTSERVER_THREAD) {
+            stopHttpService();
         }
     }
 }

src/main/java/edu/jhuapl/trinity/messages/TrinityHttpServer.java

@@ -32,28 +32,20 @@
 public class TrinityHttpServer implements Runnable {
 
     private static final Logger LOGGER = Logger.getLogger(TrinityHttpServer.class.getName());
-    private static final String HTTP_HOST = "0.0.0.0";
-    private static final int HTTP_PORT = 8080;
+    private static final String DEFAULT_HTTP_HOST = "0.0.0.0";
+    private static final int DEFAULT_HTTP_PORT = 8080;
     private final Scene scene;
-    ChannelFuture future;
-    EventLoopGroup parentGroup;
-    EventLoopGroup childGroup;      
-    ServerBootstrap bootstrap;
-
+
     public TrinityHttpServer(Scene scene) {
         this.scene = scene;
     }
-    public void stop() {
-        future.cancel(true);
-        childGroup.shutdownGracefully();
-        parentGroup.shutdownGracefully();
-    }
+
     @Override
     public void run() {
-        parentGroup = new NioEventLoopGroup();
-        childGroup = new NioEventLoopGroup();
+        EventLoopGroup parentGroup = new NioEventLoopGroup();
+        EventLoopGroup childGroup = new NioEventLoopGroup();
         try {
-            bootstrap = new ServerBootstrap()
+            ServerBootstrap bootstrap = new ServerBootstrap()
                 .group(parentGroup, childGroup)
                 .channel(NioServerSocketChannel.class)
                 .childHandler(new ChannelInitializer<SocketChannel>() {
@@ -63,11 +55,11 @@ protected void initChannel(SocketChannel ch) {
                         ch.pipeline().addLast(new HttpObjectAggregator(Integer.MAX_VALUE));
                         ch.pipeline().addLast(new TrinityServerHandler(scene));
                     }
-            });
-            future = bootstrap.bind(HTTP_HOST, HTTP_PORT).sync();
+                });
+            ChannelFuture future = bootstrap.bind(DEFAULT_HTTP_HOST, DEFAULT_HTTP_PORT).sync();
             future.channel().closeFuture().sync();
         } catch (InterruptedException ex) {
-            LOGGER.log(Level.SEVERE, null, ex);
+            LOGGER.log(Level.WARNING, "Trinity HTTP Server Stopped.");
         } finally {
             childGroup.shutdownGracefully();
             parentGroup.shutdownGracefully();
@@ -79,7 +71,7 @@ public static class TrinityServerHandler extends SimpleChannelInboundHandler<Ful
         private static final Logger LOGGER = Logger.getLogger(TrinityServerHandler.class.getName());
 
         private final MessageProcessor processor;
-        
+
         public TrinityServerHandler(Scene scene) {
             this.processor = new MessageProcessor(scene);
         }
@@ -142,4 +134,4 @@ public boolean processMessage(String messageBody) {
             }
         }
     }
-}
+}

src/main/resources/edu/jhuapl/trinity/fxml/Data.fxml

@@ -60,7 +60,7 @@
                                         </HBox>
                                         <HBox alignment="CENTER_LEFT" layoutX="10.0" layoutY="169.0" spacing="10.0">
                                             <children>
-                                                <Label prefWidth="150.0" text="REST Injection Service" />
+                                                <Label prefWidth="150.0" text="HTTP Service" />
                                                 <ToggleButton fx:id="restInjectToggleButton" minWidth="100.0" mnemonicParsing="false" onAction="#toggleRestInject" text="Enable" />
                                                 <ProgressIndicator fx:id="restProgressIndicator" prefHeight="32.0" prefWidth="32.0" style="-fx-background-color: #00000000;" />
                                             </children>