Fix Sonar smells for websocket module

* Introduce `JavaUtils` for chaining properties setting
* Fix method complexity in the `ServerWebSocketContainer` using newly
introduced `JavaUtils`
* Make `JavaUtils` as `final`

Author: artembilan

spring-integration-core/src/main/java/org/springframework/integration/util/JavaUtils.java

@@ -0,0 +1,70 @@
+/*
+ * Copyright 2019 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.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.integration.util;
+
+import java.util.function.Consumer;
+
+/**
+ * Chained utility methods to simplify some Java repetitive code. Obtain a reference to
+ * the singleton {@link #INSTANCE} and then chain calls to the utility methods.
+ *
+ * @author Gary Russell
+ * @author Artem Bilan
+ *
+ * @since 5.1.3
+ */
+public final class JavaUtils {
+
+	/**
+	 * The singleton instance of this utility class.
+	 */
+	public static final JavaUtils INSTANCE = new JavaUtils();
+
+	private JavaUtils() {
+		super();
+	}
+
+	/**
+	 * Invoke {@link Consumer#accept(Object)} with the value if the condition is true.
+	 * @param condition the condition.
+	 * @param value the value.
+	 * @param consumer the consumer.
+	 * @param <T> the value type.
+	 * @return this.
+	 */
+	public <T> JavaUtils acceptIfCondition(boolean condition, T value, Consumer<T> consumer) {
+		if (condition) {
+			consumer.accept(value);
+		}
+		return this;
+	}
+
+	/**
+	 * Invoke {@link Consumer#accept(Object)} with the value if it is not null.
+	 * @param value the value.
+	 * @param consumer the consumer.
+	 * @param <T> the value type.
+	 * @return this.
+	 */
+	public <T> JavaUtils acceptIfNotNull(T value, Consumer<T> consumer) {
+		if (value != null) {
+			consumer.accept(value);
+		}
+		return this;
+	}
+
+}

spring-integration-websocket/src/main/java/org/springframework/integration/websocket/ClientWebSocketContainer.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2014-2017 the original author or authors.
+ * Copyright 2014-2019 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.
@@ -46,6 +46,7 @@
  *
  * @author Artem Bilan
  * @author Gary Russell
+ *
  * @since 4.1
  */
 public final class ClientWebSocketContainer extends IntegrationWebSocketContainer implements SmartLifecycle {
@@ -221,7 +222,7 @@ public void startInternal() {
 		}
 
 		@Override
-		public void stopInternal() throws Exception {
+		public void stopInternal() throws Exception { // NOSONAR honor super
 			if (this.syncClientLifecycle) {
 				((Lifecycle) this.client).stop();
 			}
@@ -236,7 +237,9 @@ public void stopInternal() throws Exception {
 
 		@Override
 		protected void openConnection() {
-			logger.info("Connecting to WebSocket at " + getUri());
+			if (logger.isInfoEnabled()) {
+				logger.info("Connecting to WebSocket at " + getUri());
+			}
 			ClientWebSocketContainer.this.headers.setSecWebSocketProtocol(getSubProtocols());
 			ListenableFuture<WebSocketSession> future =
 					this.client.doHandshake(ClientWebSocketContainer.this.webSocketHandler,
@@ -262,10 +265,9 @@ public void onFailure(Throwable t) {
 		}
 
 		@Override
-		protected void closeConnection() throws Exception {
+		protected void closeConnection() throws Exception { // NOSONAR
 			if (ClientWebSocketContainer.this.clientSession != null) {
-				ClientWebSocketContainer.this.closeSession(ClientWebSocketContainer.this.clientSession,
-						CloseStatus.NORMAL);
+				closeSession(ClientWebSocketContainer.this.clientSession, CloseStatus.NORMAL);
 			}
 		}
 

spring-integration-websocket/src/main/java/org/springframework/integration/websocket/IntegrationWebSocketContainer.java

@@ -27,6 +27,7 @@
 
 import org.springframework.beans.factory.DisposableBean;
 import org.springframework.util.Assert;
+import org.springframework.util.ReflectionUtils;
 import org.springframework.web.socket.CloseStatus;
 import org.springframework.web.socket.SubProtocolCapable;
 import org.springframework.web.socket.WebSocketHandler;
@@ -52,25 +53,31 @@
  *
  * @author Artem Bilan
  * @author Gary Russell
+ *
  * @since 4.1
+ *
  * @see org.springframework.integration.websocket.inbound.WebSocketInboundChannelAdapter
  * @see org.springframework.integration.websocket.outbound.WebSocketOutboundMessageHandler
  */
 public abstract class IntegrationWebSocketContainer implements DisposableBean {
 
-	protected final Log logger = LogFactory.getLog(this.getClass());
+	public static final int DEFAULT_SEND_TIME_LIMIT = 10 * 1000;
+
+	public static final int DEFAULT_SEND_BUFFER_SIZE = 512 * 1024;
 
-	protected final WebSocketHandler webSocketHandler = new IntegrationWebSocketHandler();
+	protected final Log logger = LogFactory.getLog(getClass()); // NOSONAR
 
-	protected final Map<String, WebSocketSession> sessions = new ConcurrentHashMap<String, WebSocketSession>();
+	protected final WebSocketHandler webSocketHandler = new IntegrationWebSocketHandler(); // NOSONAR
 
-	private final List<String> supportedProtocols = new ArrayList<String>();
+	protected final Map<String, WebSocketSession> sessions = new ConcurrentHashMap<>(); // NOSONAR
+
+	private final List<String> supportedProtocols = new ArrayList<>();
 
 	private volatile WebSocketListener messageListener;
 
-	private volatile int sendTimeLimit = 10 * 1000;
+	private volatile int sendTimeLimit = DEFAULT_SEND_TIME_LIMIT;
 
-	private volatile int sendBufferSizeLimit = 512 * 1024;
+	private volatile int sendBufferSizeLimit = DEFAULT_SEND_BUFFER_SIZE;
 
 	public void setSendTimeLimit(int sendTimeLimit) {
 		this.sendTimeLimit = sendTimeLimit;
@@ -98,7 +105,7 @@ public void addSupportedProtocols(String... protocols) {
 	}
 
 	public List<String> getSubProtocols() {
-		List<String> protocols = new ArrayList<String>();
+		List<String> protocols = new ArrayList<>();
 		if (this.messageListener != null) {
 			protocols.addAll(this.messageListener.getSubProtocols());
 		}
@@ -116,14 +123,16 @@ public WebSocketSession getSession(String sessionId) {
 		return session;
 	}
 
-	public void closeSession(WebSocketSession session, CloseStatus closeStatus) throws Exception {
+	public void closeSession(WebSocketSession session, CloseStatus closeStatus)
+			throws Exception { // NOSONAR
+
 		// Session may be unresponsive so clear first
 		session.close(closeStatus);
 		this.webSocketHandler.afterConnectionClosed(session, closeStatus);
 	}
 
 	@Override
-	public void destroy() throws Exception {
+	public void destroy() {
 		try {
 			// Notify sessions to stop flushing messages
 			for (WebSocketSession session : this.sessions.values()) {
@@ -159,45 +168,54 @@ public List<String> getSubProtocols() {
 		}
 
 		@Override
-		public void afterConnectionEstablished(WebSocketSession sessionToDecorate) throws Exception { // NOSONAR SF ifce
-			WebSocketSession session = new ConcurrentWebSocketSessionDecorator(sessionToDecorate,
-					IntegrationWebSocketContainer.this.sendTimeLimit,
-					IntegrationWebSocketContainer.this.sendBufferSizeLimit);
+		public void afterConnectionEstablished(WebSocketSession sessionToDecorate)
+				throws Exception { // NOSONAR
+
+			WebSocketSession session =
+					new ConcurrentWebSocketSessionDecorator(sessionToDecorate,
+							IntegrationWebSocketContainer.this.sendTimeLimit,
+							IntegrationWebSocketContainer.this.sendBufferSizeLimit);
 
 			IntegrationWebSocketContainer.this.sessions.put(session.getId(), session);
 			if (IntegrationWebSocketContainer.this.logger.isDebugEnabled()) {
-				IntegrationWebSocketContainer.this.logger.debug("Started WebSocket session = " + session.getId() + ", number of sessions = "
-						+ IntegrationWebSocketContainer.this.sessions.size());
+				IntegrationWebSocketContainer.this.logger.debug("Started WebSocket session = " 	+
+						session.getId() + ", number of sessions = "	+
+						IntegrationWebSocketContainer.this.sessions.size());
 			}
 			if (IntegrationWebSocketContainer.this.messageListener != null) {
 				IntegrationWebSocketContainer.this.messageListener.afterSessionStarted(session);
 			}
 		}
 
 		@Override
-		public void afterConnectionClosed(WebSocketSession session, CloseStatus closeStatus) throws Exception {
+		public void afterConnectionClosed(WebSocketSession session, CloseStatus closeStatus)
+				throws Exception { // NOSONAR
+
 			WebSocketSession removed = IntegrationWebSocketContainer.this.sessions.remove(session.getId());
-			if (removed != null) {
-				if (IntegrationWebSocketContainer.this.messageListener != null) {
-					IntegrationWebSocketContainer.this.messageListener.afterSessionEnded(session, closeStatus);
-				}
+			if (removed != null && IntegrationWebSocketContainer.this.messageListener != null) {
+				IntegrationWebSocketContainer.this.messageListener.afterSessionEnded(session, closeStatus);
 			}
 		}
 
 		@Override
-		public void handleTransportError(WebSocketSession session, Throwable exception) throws Exception {
+		public void handleTransportError(WebSocketSession session, Throwable exception)
+				throws Exception { // NOSONAR
+
 			IntegrationWebSocketContainer.this.sessions.remove(session.getId());
-			throw new Exception(exception);
+			ReflectionUtils.rethrowException(exception);
 		}
 
 		@Override
-		public void handleMessage(WebSocketSession session, WebSocketMessage<?> message) throws Exception {
+		public void handleMessage(WebSocketSession session, WebSocketMessage<?> message)
+				throws Exception { // NOSONAR
+
 			if (IntegrationWebSocketContainer.this.messageListener != null) {
 				IntegrationWebSocketContainer.this.messageListener.onMessage(session, message);
 			}
 			else if (IntegrationWebSocketContainer.this.logger.isInfoEnabled()) {
-				IntegrationWebSocketContainer.this.logger.info("This 'WebSocketHandlerContainer' isn't configured with 'WebSocketMessageListener'."
-						+ " Received messages are ignored. Current message is: " + message);
+				IntegrationWebSocketContainer.this.logger.info("This 'WebSocketHandlerContainer' isn't " +
+						"configured with 'WebSocketMessageListener'." +
+						" Received messages are ignored. Current message is: " + message);
 			}
 		}
 

spring-integration-websocket/src/main/java/org/springframework/integration/websocket/ServerWebSocketContainer.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2014-2016 the original author or authors.
+ * Copyright 2014-2019 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.
@@ -20,6 +20,7 @@
 
 import org.springframework.context.Lifecycle;
 import org.springframework.context.SmartLifecycle;
+import org.springframework.integration.util.JavaUtils;
 import org.springframework.scheduling.TaskScheduler;
 import org.springframework.util.Assert;
 import org.springframework.util.ObjectUtils;
@@ -46,6 +47,7 @@
  *
  * @author Artem Bilan
  * @author Gary Russell
+ *
  * @since 4.1
  */
 public class ServerWebSocketContainer extends IntegrationWebSocketContainer
@@ -142,47 +144,38 @@ public void registerWebSocketHandlers(WebSocketHandlerRegistry registry) {
 				.addInterceptors(this.interceptors)
 				.setAllowedOrigins(this.origins);
 
+		configureSockJsOptionsIfAny(registration);
+	}
+
+	private void configureSockJsOptionsIfAny(WebSocketHandlerRegistration registration) {
 		if (this.sockJsServiceOptions != null) {
 			SockJsServiceRegistration sockJsServiceRegistration = registration.withSockJS();
-			if (this.sockJsServiceOptions.webSocketEnabled != null) {
-				sockJsServiceRegistration.setWebSocketEnabled(this.sockJsServiceOptions.webSocketEnabled);
-			}
-			if (this.sockJsServiceOptions.clientLibraryUrl != null) {
-				sockJsServiceRegistration.setClientLibraryUrl(this.sockJsServiceOptions.clientLibraryUrl);
-			}
-			if (this.sockJsServiceOptions.disconnectDelay != null) {
-				sockJsServiceRegistration.setDisconnectDelay(this.sockJsServiceOptions.disconnectDelay);
-			}
-			if (this.sockJsServiceOptions.heartbeatTime != null) {
-				sockJsServiceRegistration.setHeartbeatTime(this.sockJsServiceOptions.heartbeatTime);
-			}
-			if (this.sockJsServiceOptions.httpMessageCacheSize != null) {
-				sockJsServiceRegistration.setHttpMessageCacheSize(this.sockJsServiceOptions.httpMessageCacheSize);
-			}
-			if (this.sockJsServiceOptions.heartbeatTime != null) {
-				sockJsServiceRegistration.setHeartbeatTime(this.sockJsServiceOptions.heartbeatTime);
-			}
-			if (this.sockJsServiceOptions.sessionCookieNeeded != null) {
-				sockJsServiceRegistration.setSessionCookieNeeded(this.sockJsServiceOptions.sessionCookieNeeded);
-			}
-			if (this.sockJsServiceOptions.streamBytesLimit != null) {
-				sockJsServiceRegistration.setStreamBytesLimit(this.sockJsServiceOptions.streamBytesLimit);
-			}
-			if (this.sockJsServiceOptions.transportHandlers != null) {
-				sockJsServiceRegistration.setTransportHandlers(this.sockJsServiceOptions.transportHandlers);
-			}
-			if (this.sockJsServiceOptions.taskScheduler != null) {
-				sockJsServiceRegistration.setTaskScheduler(this.sockJsServiceOptions.taskScheduler);
-			}
-			if (this.sockJsServiceOptions.messageCodec != null) {
-				sockJsServiceRegistration.setMessageCodec(this.sockJsServiceOptions.messageCodec);
-			}
-			if (this.sockJsServiceOptions.suppressCors != null) {
-				sockJsServiceRegistration.setSupressCors(this.sockJsServiceOptions.suppressCors);
-			}
-
+			JavaUtils.INSTANCE
+					.acceptIfNotNull(this.sockJsServiceOptions.webSocketEnabled,
+							sockJsServiceRegistration::setWebSocketEnabled)
+					.acceptIfNotNull(this.sockJsServiceOptions.clientLibraryUrl,
+							sockJsServiceRegistration::setClientLibraryUrl)
+					.acceptIfNotNull(this.sockJsServiceOptions.disconnectDelay,
+							sockJsServiceRegistration::setDisconnectDelay)
+					.acceptIfNotNull(this.sockJsServiceOptions.heartbeatTime,
+							sockJsServiceRegistration::setHeartbeatTime)
+					.acceptIfNotNull(this.sockJsServiceOptions.httpMessageCacheSize,
+							sockJsServiceRegistration::setHttpMessageCacheSize)
+					.acceptIfNotNull(this.sockJsServiceOptions.heartbeatTime,
+							sockJsServiceRegistration::setHeartbeatTime)
+					.acceptIfNotNull(this.sockJsServiceOptions.sessionCookieNeeded,
+							sockJsServiceRegistration::setSessionCookieNeeded)
+					.acceptIfNotNull(this.sockJsServiceOptions.streamBytesLimit,
+							sockJsServiceRegistration::setStreamBytesLimit)
+					.acceptIfNotNull(this.sockJsServiceOptions.transportHandlers,
+							sockJsServiceRegistration::setTransportHandlers)
+					.acceptIfNotNull(this.sockJsServiceOptions.taskScheduler,
+							sockJsServiceRegistration::setTaskScheduler)
+					.acceptIfNotNull(this.sockJsServiceOptions.messageCodec,
+							sockJsServiceRegistration::setMessageCodec)
+					.acceptIfNotNull(this.sockJsServiceOptions.suppressCors,
+							sockJsServiceRegistration::setSupressCors);
 		}
-
 	}
 
 	public void setAutoStartup(boolean autoStartup) {