Atomic processing of create/remove of keepalive thread

Author: jpechane

src/main/java/com/github/shyiko/mysql/binlog/BinaryLogClient.java

@@ -163,6 +163,7 @@ public X509Certificate[] getAcceptedIssuers() {
     private volatile ExecutorService keepAliveThreadExecutor;
 
     private final Lock connectLock = new ReentrantLock();
+    private final Lock keepAliveThreadExecutorLock = new ReentrantLock();
 
     /**
      * Alias for BinaryLogClient("localhost", 3306, <no schema> = null, username, password).
@@ -735,46 +736,51 @@ public Thread newThread(Runnable runnable) {
                     return newNamedThread(runnable, "blc-keepalive-" + hostname + ":" + port);
                 }
             });
-        threadExecutor.submit(new Runnable() {
-            @Override
-            public void run() {
-                while (!threadExecutor.isShutdown()) {
-                    try {
-                        Thread.sleep(keepAliveInterval);
-                    } catch (InterruptedException e) {
-                        // expected in case of disconnect
-                    }
-                    if (threadExecutor.isShutdown()) {
-                        return;
-                    }
-                    boolean connectionLost = false;
-                    if (heartbeatInterval > 0) {
-                        connectionLost = System.currentTimeMillis() - eventLastSeen > keepAliveInterval;
-                    } else {
+        try {
+            keepAliveThreadExecutorLock.lock();
+            threadExecutor.submit(new Runnable() {
+                @Override
+                public void run() {
+                    while (!threadExecutor.isShutdown()) {
                         try {
-                            channel.write(new PingCommand());
-                        } catch (IOException e) {
-                            connectionLost = true;
+                            Thread.sleep(keepAliveInterval);
+                        } catch (InterruptedException e) {
+                            // expected in case of disconnect
                         }
-                    }
-                    if (connectionLost) {
-                        if (logger.isLoggable(Level.INFO)) {
-                            logger.info("Trying to restore lost connection to " + hostname + ":" + port);
+                        if (threadExecutor.isShutdown()) {
+                            return;
                         }
-                        try {
-                            terminateConnect();
-                            connect(connectTimeout);
-                        } catch (Exception ce) {
-                            if (logger.isLoggable(Level.WARNING)) {
-                                logger.warning("Failed to restore connection to " + hostname + ":" + port +
-                                    ". Next attempt in " + keepAliveInterval + "ms");
+                        boolean connectionLost = false;
+                        if (heartbeatInterval > 0) {
+                            connectionLost = System.currentTimeMillis() - eventLastSeen > keepAliveInterval;
+                        } else {
+                            try {
+                                channel.write(new PingCommand());
+                            } catch (IOException e) {
+                                connectionLost = true;
+                            }
+                        }
+                        if (connectionLost) {
+                            if (logger.isLoggable(Level.INFO)) {
+                                logger.info("Trying to restore lost connection to " + hostname + ":" + port);
+                            }
+                            try {
+                                terminateConnect();
+                                connect(connectTimeout);
+                            } catch (Exception ce) {
+                                if (logger.isLoggable(Level.WARNING)) {
+                                    logger.warning("Failed to restore connection to " + hostname + ":" + port +
+                                        ". Next attempt in " + keepAliveInterval + "ms");
+                                }
                             }
                         }
                     }
                 }
-            }
-        });
-        keepAliveThreadExecutor = threadExecutor;
+            });
+            keepAliveThreadExecutor = threadExecutor;
+        } finally {
+            keepAliveThreadExecutorLock.unlock();
+        }
     }
 
     private Thread newNamedThread(Runnable runnable, String threadName) {
@@ -784,7 +790,12 @@ private Thread newNamedThread(Runnable runnable, String threadName) {
     }
 
     boolean isKeepAliveThreadRunning() {
-        return keepAliveThreadExecutor != null && !keepAliveThreadExecutor.isShutdown();
+        try {
+            keepAliveThreadExecutorLock.lock();
+            return keepAliveThreadExecutor != null && !keepAliveThreadExecutor.isShutdown();
+        } finally {
+            keepAliveThreadExecutorLock.unlock();
+        }
     }
 
     /**
@@ -1134,14 +1145,19 @@ public void disconnect() throws IOException {
     }
 
     private void terminateKeepAliveThread() {
-        ExecutorService keepAliveThreadExecutor = this.keepAliveThreadExecutor;
-        if (keepAliveThreadExecutor == null) {
-            return;
-        }
-        keepAliveThreadExecutor.shutdownNow();
-        while (!awaitTerminationInterruptibly(keepAliveThreadExecutor,
-            Long.MAX_VALUE, TimeUnit.NANOSECONDS)) {
-            // ignore
+        try {
+            keepAliveThreadExecutorLock.lock();
+            ExecutorService keepAliveThreadExecutor = this.keepAliveThreadExecutor;
+            if (keepAliveThreadExecutor == null) {
+                return;
+            }
+            keepAliveThreadExecutor.shutdownNow();
+            while (!awaitTerminationInterruptibly(keepAliveThreadExecutor,
+                Long.MAX_VALUE, TimeUnit.NANOSECONDS)) {
+                // ignore
+            }
+        } finally {
+            keepAliveThreadExecutorLock.unlock();
         }
     }