Replace TimerTask with ScheduledExecutorService (#878)

Replace TimerTask with ScheduledExecutorService

src/main/java/org/java_websocket/AbstractWebSocket.java

@@ -26,13 +26,16 @@
 package org.java_websocket;
 
 import org.java_websocket.framing.CloseFrame;
+import org.java_websocket.util.NamedThreadFactory;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
 import java.util.ArrayList;
 import java.util.Collection;
-import java.util.Timer;
-import java.util.TimerTask;
+import java.util.concurrent.Executors;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.ScheduledFuture;
+import java.util.concurrent.TimeUnit;
 
 
 /**
@@ -60,21 +63,21 @@ public abstract class AbstractWebSocket extends WebSocketAdapter {
 	private boolean reuseAddr;
 
 	/**
-     * Attribute for a timer allowing to check for lost connections
-	 * @since 1.3.4
+     * Attribute for a service that triggers lost connection checking
+	 * @since 1.4.1
      */
-    private Timer connectionLostTimer;
+    private ScheduledExecutorService connectionLostCheckerService;
     /**
-     * Attribute for a timertask allowing to check for lost connections
-	 * @since 1.3.4
+     * Attribute for a task that checks for lost connections
+	 * @since 1.4.1
      */
-    private TimerTask connectionLostTimerTask;
+    private ScheduledFuture connectionLostCheckerFuture;
 
     /**
-     * Attribute for the lost connection check interval
+     * Attribute for the lost connection check interval in nanoseconds
 	 * @since 1.3.4
      */
-    private int connectionLostTimeout = 60;
+    private long connectionLostTimeout = TimeUnit.SECONDS.toNanos(60);
 
 	/**
 	 * Attribute to keep track if the WebSocket Server/Client is running/connected
@@ -89,12 +92,12 @@ public abstract class AbstractWebSocket extends WebSocketAdapter {
     /**
      * Get the interval checking for lost connections
      * Default is 60 seconds
-     * @return the interval
+     * @return the interval in seconds
 	 * @since 1.3.4
      */
     public int getConnectionLostTimeout() {
 		synchronized (syncConnectionLost) {
-			return connectionLostTimeout;
+			return (int) TimeUnit.NANOSECONDS.toSeconds(connectionLostTimeout);
 		}
     }
 
@@ -107,7 +110,7 @@ public int getConnectionLostTimeout() {
      */
     public void setConnectionLostTimeout( int connectionLostTimeout ) {
         synchronized (syncConnectionLost) {
-            this.connectionLostTimeout = connectionLostTimeout;
+            this.connectionLostTimeout = TimeUnit.SECONDS.toNanos(connectionLostTimeout);
             if (this.connectionLostTimeout <= 0) {
                 log.trace("Connection lost timer stopped");
                 cancelConnectionLostTimer();
@@ -139,7 +142,7 @@ public void setConnectionLostTimeout( int connectionLostTimeout ) {
      */
     protected void stopConnectionLostTimer() {
         synchronized (syncConnectionLost) {
-            if (connectionLostTimer != null || connectionLostTimerTask != null) {
+            if (connectionLostCheckerService != null || connectionLostCheckerFuture != null) {
                 this.websocketRunning = false;
                 log.trace("Connection lost timer stopped");
                 cancelConnectionLostTimer();
@@ -168,8 +171,8 @@ protected void startConnectionLostTimer() {
 	 */
 	private void restartConnectionLostTimer() {
 		cancelConnectionLostTimer();
-		connectionLostTimer = new Timer("WebSocketTimer");
-		connectionLostTimerTask = new TimerTask() {
+		connectionLostCheckerService = Executors.newSingleThreadScheduledExecutor(new NamedThreadFactory("connectionLostChecker"));
+		Runnable connectionLostChecker = new Runnable() {
 
 			/**
 			 * Keep the connections in a separate list to not cause deadlocks
@@ -180,31 +183,31 @@ public void run() {
 				connections.clear();
 				try {
 					connections.addAll( getConnections() );
-					long current = ( System.currentTimeMillis() - ( connectionLostTimeout * 1500 ) );
+					long minimumPongTime = (long) (System.nanoTime() - ( connectionLostTimeout * 1.5 ));
 					for( WebSocket conn : connections ) {
-						executeConnectionLostDetection(conn, current);
+						executeConnectionLostDetection(conn, minimumPongTime);
 					}
 				} catch ( Exception e ) {
 					//Ignore this exception
 				}
 				connections.clear();
 			}
 		};
-		connectionLostTimer.scheduleAtFixedRate( connectionLostTimerTask,1000L*connectionLostTimeout , 1000L*connectionLostTimeout );
 
+		connectionLostCheckerFuture = connectionLostCheckerService.scheduleAtFixedRate(connectionLostChecker, connectionLostTimeout, connectionLostTimeout, TimeUnit.NANOSECONDS);
 	}
 
 	/**
 	 * Send a ping to the endpoint or close the connection since the other endpoint did not respond with a ping
 	 * @param webSocket the websocket instance
-	 * @param current the current time in milliseconds
+	 * @param minimumPongTime the lowest/oldest allowable last pong time (in nanoTime) before we consider the connection to be lost
 	 */
-	private void executeConnectionLostDetection(WebSocket webSocket, long current) {
+	private void executeConnectionLostDetection(WebSocket webSocket, long minimumPongTime) {
 		if (!(webSocket instanceof WebSocketImpl)) {
 			return;
 		}
 		WebSocketImpl webSocketImpl = (WebSocketImpl) webSocket;
-		if( webSocketImpl.getLastPong() < current ) {
+		if( webSocketImpl.getLastPong() < minimumPongTime ) {
 			log.trace("Closing connection due to no pong received: {}", webSocketImpl);
 			webSocketImpl.closeConnection( CloseFrame.ABNORMAL_CLOSE, "The connection was closed because the other endpoint did not respond with a pong in time. For more information check: https://github.com/TooTallNate/Java-WebSocket/wiki/Lost-connection-detection" );
 		} else {
@@ -228,13 +231,13 @@ private void executeConnectionLostDetection(WebSocket webSocket, long current) {
 	 * @since 1.3.4
      */
     private void cancelConnectionLostTimer() {
-        if( connectionLostTimer != null ) {
-            connectionLostTimer.cancel();
-            connectionLostTimer = null;
+       if( connectionLostCheckerService != null ) {
+            connectionLostCheckerService.shutdownNow();
+            connectionLostCheckerService = null;
         }
-        if( connectionLostTimerTask != null ) {
-            connectionLostTimerTask.cancel();
-            connectionLostTimerTask = null;
+        if( connectionLostCheckerFuture != null ) {
+        	connectionLostCheckerFuture.cancel(false);
+            connectionLostCheckerFuture = null;
         }
     }
 

src/main/java/org/java_websocket/WebSocketImpl.java

@@ -151,7 +151,7 @@ public class WebSocketImpl implements WebSocket {
 	/**
 	 * Attribute, when the last pong was recieved
 	 */
-	private long lastPong = System.currentTimeMillis();
+	private long lastPong = System.nanoTime();
 
 	/**
 	 * Attribut to synchronize the write
@@ -802,7 +802,7 @@ long getLastPong() {
 	 * Update the timestamp when the last pong was received
 	 */
 	public void updateLastPong() {
-		this.lastPong = System.currentTimeMillis();
+		this.lastPong = System.nanoTime();
 	}
 
 	/**

src/main/java/org/java_websocket/util/NamedThreadFactory.java

@@ -0,0 +1,47 @@
+/*
+ *  Copyright (c) 2010-2019 Nathan Rajlich
+ *
+ * Permission is hereby granted, free of charge, to any person
+ * obtaining a copy of this software and associated documentation
+ * files (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following
+ * conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+ * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+ * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+ * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+package org.java_websocket.util;
+
+import java.util.concurrent.Executors;
+import java.util.concurrent.ThreadFactory;
+import java.util.concurrent.atomic.AtomicInteger;
+
+public class NamedThreadFactory implements ThreadFactory {
+        private final ThreadFactory defaultThreadFactory = Executors.defaultThreadFactory();
+        private final AtomicInteger threadNumber = new AtomicInteger(1);
+        private final String threadPrefix;
+
+        public NamedThreadFactory(String threadPrefix) {
+            this.threadPrefix = threadPrefix;
+        }
+
+        @Override
+        public Thread newThread(Runnable runnable) {
+            Thread thread = defaultThreadFactory.newThread(runnable);
+            thread.setName(threadPrefix + "-" + threadNumber);
+            return thread;
+        }
+}

src/test/java/org/java_websocket/issues/Issue666Test.java

@@ -80,7 +80,7 @@ public void onStart() {
 		}
 		for( Thread thread : mapAfter.values() ) {
 			String name = thread.getName();
-			if( !name.startsWith( "WebSocketSelector-" ) && !name.startsWith( "WebSocketWorker-" ) && !name.equals( "WebSocketTimer" ) ) {
+			if( !name.startsWith( "WebSocketSelector-" ) && !name.startsWith( "WebSocketWorker-" ) && !name.startsWith( "connectionLostChecker-" ) ) {
 				Assert.fail( "Thread not correctly named! Is: " + name );
 			}
 		}
@@ -145,7 +145,7 @@ public void onStart() {
 		}
 		for( Thread thread : mapAfter.values() ) {
 			String name = thread.getName();
-			if( !name.equals( "WebSocketTimer" ) && !name.startsWith( "WebSocketWriteThread-" ) && !name.startsWith( "WebSocketConnectReadThread-" )) {
+			if( !name.startsWith( "connectionLostChecker-" ) && !name.startsWith( "WebSocketWriteThread-" ) && !name.startsWith( "WebSocketConnectReadThread-" )) {
 				Assert.fail( "Thread not correctly named! Is: " + name );
 			}
 		}