Consistent volatile access to running flag in Lifecycle implementations

Issue: SPR-16596
Issue: SPR-16488

(cherry picked from commit d4a8f76)

Author: jhoeller

Diff for: spring-jms/src/main/java/org/springframework/jms/listener/AbstractJmsListeningContainer.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2018 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -76,7 +76,7 @@ public abstract class AbstractJmsListeningContainer extends JmsDestinationAccess
 
 	private boolean active = false;
 
-	private boolean running = false;
+	private volatile boolean running = false;
 
 	private final List<Object> pausedTasks = new LinkedList<Object>();
 
@@ -344,9 +344,7 @@ protected void doStop() throws JMSException {
 	 */
 	@Override
 	public final boolean isRunning() {
-		synchronized (this.lifecycleMonitor) {
-			return (this.running && runningAllowed());
-		}
+		return (this.running && runningAllowed());
 	}
 
 	/**

Diff for: spring-messaging/src/main/java/org/springframework/messaging/simp/annotation/support/SimpAnnotationMethodMessageHandler.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2017 the original author or authors.
+ * Copyright 2002-2018 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -111,10 +111,10 @@ public class SimpAnnotationMethodMessageHandler extends AbstractMethodMessageHan
 
 	private MessageHeaderInitializer headerInitializer;
 
-	private final Object lifecycleMonitor = new Object();
-
 	private volatile boolean running = false;
 
+	private final Object lifecycleMonitor = new Object();
+
 
 	/**
 	 * Create an instance of SimpAnnotationMethodMessageHandler with the given
@@ -298,9 +298,7 @@ public final void stop(Runnable callback) {
 
 	@Override
 	public final boolean isRunning() {
-		synchronized (this.lifecycleMonitor) {
-			return this.running;
-		}
+		return this.running;
 	}
 
 

Diff for: spring-messaging/src/main/java/org/springframework/messaging/simp/broker/AbstractBrokerMessageHandler.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2017 the original author or authors.
+ * Copyright 2002-2018 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -153,9 +153,7 @@ public int getPhase() {
 	@Override
 	public void start() {
 		synchronized (this.lifecycleMonitor) {
-			if (logger.isInfoEnabled()) {
-				logger.info("Starting...");
-			}
+			logger.info("Starting...");
 			this.clientInboundChannel.subscribe(this);
 			this.brokerChannel.subscribe(this);
 			if (this.clientInboundChannel instanceof InterceptableChannel) {
@@ -173,9 +171,7 @@ protected void startInternal() {
 	@Override
 	public void stop() {
 		synchronized (this.lifecycleMonitor) {
-			if (logger.isInfoEnabled()) {
-				logger.info("Stopping...");
-			}
+			logger.info("Stopping...");
 			stopInternal();
 			this.clientInboundChannel.unsubscribe(this);
 			this.brokerChannel.unsubscribe(this);
@@ -206,9 +202,7 @@ public final void stop(Runnable callback) {
 	 */
 	@Override
 	public final boolean isRunning() {
-		synchronized (this.lifecycleMonitor) {
-			return this.running;
-		}
+		return this.running;
 	}
 
 	/**

Diff for: spring-messaging/src/main/java/org/springframework/messaging/simp/user/UserDestinationMessageHandler.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2018 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -64,10 +64,10 @@ public class UserDestinationMessageHandler implements MessageHandler, SmartLifec
 
 	private MessageHeaderInitializer headerInitializer;
 
-	private final Object lifecycleMonitor = new Object();
-
 	private volatile boolean running = false;
 
+	private final Object lifecycleMonitor = new Object();
+
 
 	/**
 	 * Create an instance with the given client and broker channels subscribing
@@ -180,9 +180,7 @@ public final void stop(Runnable callback) {
 
 	@Override
 	public final boolean isRunning() {
-		synchronized (this.lifecycleMonitor) {
-			return this.running;
-		}
+		return this.running;
 	}
 
 

Diff for: spring-tx/src/main/java/org/springframework/jca/endpoint/GenericMessageEndpointManager.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2018 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -156,7 +156,7 @@ public class GenericMessageEndpointManager implements SmartLifecycle, Initializi
 
 	private int phase = Integer.MAX_VALUE;
 
-	private boolean running = false;
+	private volatile boolean running = false;
 
 	private final Object lifecycleMonitor = new Object();
 
@@ -318,9 +318,7 @@ public void stop(Runnable callback) {
 	 */
 	@Override
 	public boolean isRunning() {
-		synchronized (this.lifecycleMonitor) {
-			return this.running;
-		}
+		return this.running;
 	}
 
 	/**

Diff for: spring-websocket/src/main/java/org/springframework/web/socket/client/ConnectionManagerSupport.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2018 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -38,15 +38,14 @@ public abstract class ConnectionManagerSupport implements SmartLifecycle {
 
 	protected final Log logger = LogFactory.getLog(getClass());
 
-
 	private final URI uri;
 
 	private boolean autoStartup = false;
 
-	private boolean running = false;
-
 	private int phase = Integer.MAX_VALUE;
 
+	private volatile boolean running = false;
+
 	private final Object lifecycleMonitor = new Object();
 
 
@@ -161,9 +160,7 @@ protected void stopInternal() throws Exception {
 	 */
 	@Override
 	public boolean isRunning() {
-		synchronized (this.lifecycleMonitor) {
-			return this.running;
-		}
+		return this.running;
 	}
 
 

Diff for: spring-websocket/src/main/java/org/springframework/web/socket/client/jetty/JettyWebSocketClient.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2017 the original author or authors.
+ * Copyright 2002-2018 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -60,8 +60,6 @@ public class JettyWebSocketClient extends AbstractWebSocketClient implements Lif
 
 	private final org.eclipse.jetty.websocket.client.WebSocketClient client;
 
-	private final Object lifecycleMonitor = new Object();
-
 	private AsyncListenableTaskExecutor taskExecutor = new SimpleAsyncTaskExecutor();
 
 
@@ -99,47 +97,33 @@ public AsyncListenableTaskExecutor getTaskExecutor() {
 		return this.taskExecutor;
 	}
 
-	@Override
-	public boolean isRunning() {
-		synchronized (this.lifecycleMonitor) {
-			return this.client.isStarted();
-		}
-	}
 
 	@Override
 	public void start() {
-		synchronized (this.lifecycleMonitor) {
-			if (!isRunning()) {
-				try {
-					if (logger.isInfoEnabled()) {
-						logger.info("Starting Jetty WebSocketClient");
-					}
-					this.client.start();
-				}
-				catch (Exception ex) {
-					throw new IllegalStateException("Failed to start Jetty client", ex);
-				}
-			}
+		try {
+			this.client.start();
+		}
+		catch (Exception ex) {
+			throw new IllegalStateException("Failed to start Jetty WebSocketClient", ex);
 		}
 	}
 
 	@Override
 	public void stop() {
-		synchronized (this.lifecycleMonitor) {
-			if (isRunning()) {
-				try {
-					if (logger.isInfoEnabled()) {
-						logger.info("Stopping Jetty WebSocketClient");
-					}
-					this.client.stop();
-				}
-				catch (Exception ex) {
-					logger.error("Error stopping Jetty WebSocketClient", ex);
-				}
-			}
+		try {
+			this.client.stop();
+		}
+		catch (Exception ex) {
+			logger.error("Failed to stop Jetty WebSocketClient", ex);
 		}
 	}
 
+	@Override
+	public boolean isRunning() {
+		return this.client.isStarted();
+	}
+
+
 	@Override
 	public ListenableFuture<WebSocketSession> doHandshake(WebSocketHandler webSocketHandler,
 			String uriTemplate, Object... uriVars) {

Diff for: spring-websocket/src/main/java/org/springframework/web/socket/messaging/SubProtocolWebSocketHandler.java

@@ -102,10 +102,10 @@ public class SubProtocolWebSocketHandler
 
 	private final Stats stats = new Stats();
 
-	private final Object lifecycleMonitor = new Object();
-
 	private volatile boolean running = false;
 
+	private final Object lifecycleMonitor = new Object();
+
 
 	/**
 	 * Create a new {@code SubProtocolWebSocketHandler} for the given inbound and outbound channels.
@@ -279,9 +279,7 @@ public final void stop(Runnable callback) {
 
 	@Override
 	public final boolean isRunning() {
-		synchronized (this.lifecycleMonitor) {
-			return this.running;
-		}
+		return this.running;
 	}
 
 

Diff for: spring-websocket/src/main/java/org/springframework/web/socket/messaging/WebSocketStompClient.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2018 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -72,17 +72,16 @@ public class WebSocketStompClient extends StompClientSupport implements SmartLif
 
 	private static final Log logger = LogFactory.getLog(WebSocketStompClient.class);
 
-
 	private final WebSocketClient webSocketClient;
 
 	private int inboundMessageSizeLimit = 64 * 1024;
 
 	private boolean autoStartup = true;
 
-	private boolean running = false;
-
 	private int phase = Integer.MAX_VALUE;
 
+	private volatile boolean running = false;
+
 
 	/**
 	 * Class constructor. Sets {@link #setDefaultHeartbeat} to "0,0" but will

Diff for: spring-websocket/src/main/java/org/springframework/web/socket/server/support/AbstractHandshakeHandler.java

@@ -186,10 +186,6 @@ public String[] getSupportedProtocols() {
 		return StringUtils.toStringArray(this.supportedProtocols);
 	}
 
-	@Override
-	public boolean isRunning() {
-		return this.running;
-	}
 
 	@Override
 	public void start() {
@@ -219,6 +215,11 @@ protected void doStop() {
 		}
 	}
 
+	@Override
+	public boolean isRunning() {
+		return this.running;
+	}
+
 
 	@Override
 	public final boolean doHandshake(ServerHttpRequest request, ServerHttpResponse response,

Diff for: spring-websocket/src/main/java/org/springframework/web/socket/server/support/WebSocketHttpRequestHandler.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2015 the original author or authors.
+ * Copyright 2002-2018 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -21,7 +21,6 @@
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
-
 import javax.servlet.ServletContext;
 import javax.servlet.ServletException;
 import javax.servlet.http.HttpServletRequest;
@@ -119,10 +118,6 @@ public void setServletContext(ServletContext servletContext) {
 		}
 	}
 
-	@Override
-	public boolean isRunning() {
-		return this.running;
-	}
 
 	@Override
 	public void start() {
@@ -144,6 +139,11 @@ public void stop() {
 		}
 	}
 
+	@Override
+	public boolean isRunning() {
+		return this.running;
+	}
+
 
 	@Override
 	public void handleRequest(HttpServletRequest servletRequest, HttpServletResponse servletResponse)