Fix Sonar smells for HTTP & WebFlux modules (#2810)

* Fix Sonar smells for HTTP & WebFlux modules

* * Fix more HTTP Sonar smells

* * Remove unused import
* Fix complexity in the `IntegrationMBeanExporter.enhanceSourceMonitor()`

* * Remove unused `IntegrationMBeanExporter.getField()` method

* * Remove unused import in the `IntegrationMBeanExporter`

Author: artembilan

spring-integration-http/src/main/java/org/springframework/integration/http/inbound/BaseHttpInboundEndpoint.java

@@ -28,7 +28,6 @@
 import org.springframework.http.HttpEntity;
 import org.springframework.http.HttpHeaders;
 import org.springframework.http.HttpMethod;
-import org.springframework.http.HttpRequest;
 import org.springframework.http.HttpStatus;
 import org.springframework.integration.context.OrderlyShutdownCapable;
 import org.springframework.integration.expression.ExpressionUtils;
@@ -51,20 +50,20 @@
  */
 public class BaseHttpInboundEndpoint extends MessagingGatewaySupport implements OrderlyShutdownCapable {
 
-	protected static final boolean jaxb2Present = // NOSONAR lower case static
+	protected static final boolean JAXB_PRESENT =
 			ClassUtils.isPresent("javax.xml.bind.Binder",
 					BaseHttpInboundEndpoint.class.getClassLoader());
 
-	protected static final boolean romeToolsPresent = // NOSONAR lower case static
+	protected static final boolean ROME_TOOLS_PRESENT =
 			ClassUtils.isPresent("com.rometools.rome.feed.atom.Feed",
 					BaseHttpInboundEndpoint.class.getClassLoader());
 
-	protected static final List<HttpMethod> nonReadableBodyHttpMethods = // NOSONAR lower case static
+	protected static final List<HttpMethod> NON_READABLE_BODY_HTTP_METHODS =
 			Arrays.asList(HttpMethod.GET, HttpMethod.HEAD, HttpMethod.OPTIONS);
 
-	protected final boolean expectReply;
+	protected final AtomicInteger activeCount = new AtomicInteger(); // NOSONAR
 
-	protected final AtomicInteger activeCount = new AtomicInteger();
+	private final boolean expectReply;
 
 	private ResolvableType requestPayloadType = null;
 
@@ -268,13 +267,12 @@ protected void onInit() {
 	}
 
 	private void validateSupportedMethods() {
-		if (this.requestPayloadType != null
-				&& CollectionUtils.containsAny(nonReadableBodyHttpMethods,
-				Arrays.asList(getRequestMapping().getMethods()))) {
-			if (logger.isWarnEnabled()) {
-				logger.warn("The 'requestPayloadType' attribute will have no relevance for one " +
-						"of the specified HTTP methods '" + nonReadableBodyHttpMethods + "'");
-			}
+		if (this.requestPayloadType != null && logger.isWarnEnabled() &&
+				CollectionUtils.containsAny(NON_READABLE_BODY_HTTP_METHODS,
+						Arrays.asList(getRequestMapping().getMethods()))) {
+
+			logger.warn("The 'requestPayloadType' attribute will have no relevance for one " +
+					"of the specified HTTP methods '" + NON_READABLE_BODY_HTTP_METHODS + "'");
 		}
 	}
 
@@ -329,11 +327,11 @@ public String getComponentType() {
 
 	/**
 	 * Checks if the request has a readable body (not a GET, HEAD, or OPTIONS request).
-	 * @param request the HTTP request to check the method
+	 * @param httpMethod the HTTP method to check
 	 * @return true or false if HTTP request can contain the body
 	 */
-	protected boolean isReadable(HttpRequest request) {
-		return !(CollectionUtils.containsInstance(nonReadableBodyHttpMethods, request.getMethod()));
+	protected boolean isReadable(HttpMethod httpMethod) {
+		return !(CollectionUtils.containsInstance(NON_READABLE_BODY_HTTP_METHODS, httpMethod));
 	}
 
 }

spring-integration-http/src/main/java/org/springframework/integration/http/inbound/HttpRequestHandlingController.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2019 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.
@@ -45,9 +45,9 @@
  * <p>
  * This endpoint will have request/reply behavior by default. That can be overridden by passing <code>false</code> to
  * the constructor. In the request/reply case, the core map will be passed to the view, and it will contain either the
- * reply Message or payload depending on the value of {@link #extractReplyPayload} (true by default, meaning just the
- * payload). The corresponding key in the map is determined by the {@link #replyKey} property (with a default of
- * "reply").
+ * reply Message or payload depending on the value of {@link #setExtractReplyPayload(boolean)}
+ * (true by default, meaning just the payload).
+ * The corresponding key in the map is determined by the {@link #replyKey} property (with a default of "reply").
  *
  * @author Mark Fisher
  * @author Gary Russell
@@ -72,15 +72,15 @@ public class HttpRequestHandlingController extends HttpRequestHandlingEndpointSu
 	 */
 	public static final String DEFAULT_ERRORS_KEY = "errors";
 
-	private volatile Expression viewExpression;
+	private Expression viewExpression;
 
-	private volatile StandardEvaluationContext evaluationContext;
+	private StandardEvaluationContext evaluationContext;
 
-	private volatile String replyKey = DEFAULT_REPLY_KEY;
+	private String replyKey = DEFAULT_REPLY_KEY;
 
-	private volatile String errorsKey = DEFAULT_ERRORS_KEY;
+	private String errorsKey = DEFAULT_ERRORS_KEY;
 
-	private volatile String errorCode = DEFAULT_ERROR_CODE;
+	private String errorCode = DEFAULT_ERROR_CODE;
 
 	public HttpRequestHandlingController() {
 		this(true);
@@ -157,7 +157,7 @@ public final ModelAndView handleRequest(HttpServletRequest servletRequest, HttpS
 
 			RequestEntity<Object> httpEntity = prepareRequestEntity(request);
 
-			Message<?> replyMessage = doHandleRequest(servletRequest, httpEntity, servletResponse);
+			Message<?> replyMessage = doHandleRequest(servletRequest, httpEntity);
 			ServletServerHttpResponse response = new ServletServerHttpResponse(servletResponse);
 			if (replyMessage != null) {
 				Object reply = setupResponseAndConvertReply(response, replyMessage);