Update information on WebApplicationContext hierarchy

Issue: SPR-16041

spring-webflux/src/main/java/org/springframework/web/reactive/support/AbstractAnnotationConfigDispatcherHandlerInitializer.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2017 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.
@@ -20,13 +20,11 @@ import org.springframework.context.ApplicationContext;
 import org.springframework.context.annotation.AnnotationConfigApplicationContext;
 import org.springframework.http.server.reactive.ServletHttpHandlerAdapter;
 import org.springframework.util.ObjectUtils;
-import org.springframework.web.reactive.DispatcherHandler;
 
 /**
- * Base class for {@link org.springframework.web.WebApplicationInitializer}
- * implementations that register a {@link DispatcherHandler} configured with annotated
- * {@link org.springframework.context.annotation.Configuration @Configuration} classes in the
- * servlet context, wrapping it in a {@link ServletHttpHandlerAdapter}.
+ * {@link org.springframework.web.WebApplicationInitializer WebApplicationInitializer}
+ * to register a {@code DispatcherHandler}, wrapping it in a
+ * {@link ServletHttpHandlerAdapter}, and use Java-based Spring configuration.
  *
  * <p>Concrete implementations are required to implement {@link #getConfigClasses()}.
  * Further template and customization methods are provided by
@@ -38,6 +36,7 @@ import org.springframework.web.reactive.DispatcherHandler;
 public abstract class AbstractAnnotationConfigDispatcherHandlerInitializer
 		extends AbstractDispatcherHandlerInitializer {
 
+
 	/**
 	 * {@inheritDoc}
 	 * <p>This implementation creates an {@link AnnotationConfigApplicationContext},
@@ -45,19 +44,18 @@ public abstract class AbstractAnnotationConfigDispatcherHandlerInitializer
 	 */
 	@Override
 	protected ApplicationContext createApplicationContext() {
-		AnnotationConfigApplicationContext servletAppContext = new AnnotationConfigApplicationContext();
+		AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext();
 		Class<?>[] configClasses = getConfigClasses();
 		if (!ObjectUtils.isEmpty(configClasses)) {
-			servletAppContext.register(configClasses);
+			context.register(configClasses);
 		}
-		return servletAppContext;
+		return context;
 	}
 
 	/**
-	 * Specify {@link org.springframework.context.annotation.Configuration @Configuration}
-	 * and/or {@link org.springframework.stereotype.Component @Component} classes to be
-	 * provided to the {@linkplain #createApplicationContext() application context}.
-	 * @return the configuration classes for the dispatcher servlet application context
+	 * Specify {@code @Configuration} and/or {@code @Component} classes for
+	 * the {@linkplain #createApplicationContext() application context}.
+	 * @return the configuration for the application context
 	 */
 	protected abstract Class<?>[] getConfigClasses();
 

spring-webflux/src/main/java/org/springframework/web/reactive/support/AbstractDispatcherHandlerInitializer.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2017 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.
@@ -34,16 +34,15 @@ import org.springframework.web.server.adapter.HttpWebHandlerAdapter;
 
 /**
  * Base class for {@link org.springframework.web.WebApplicationInitializer}
- * implementations that register a {@link DispatcherHandler} in the servlet context, wrapping it in
- * a {@link ServletHttpHandlerAdapter}.
+ * implementations that register a {@link DispatcherHandler} in the servlet
+ * context, wrapping it in a {@link ServletHttpHandlerAdapter}.
  *
- * <p>Concrete implementations are required to implement
- * {@link #createApplicationContext()}, which gets invoked from
- * {@link #registerDispatcherHandler(ServletContext)}. Further customization can be achieved by
- * overriding {@link #customizeRegistration(ServletRegistration.Dynamic)}.
+ * <p>Most applications should consider extending the Spring Java config, sub-class
+ * {@link AbstractAnnotationConfigDispatcherHandlerInitializer}.
  *
  * @author Arjen Poutsma
  * @since 5.0
+ * @see AbstractServletHttpHandlerAdapterInitializer
  */
 public abstract class AbstractDispatcherHandlerInitializer implements WebApplicationInitializer {
 

spring-webflux/src/main/java/org/springframework/web/reactive/support/AbstractServletHttpHandlerAdapterInitializer.java

@@ -27,16 +27,15 @@ import org.springframework.web.WebApplicationInitializer;
 
 /**
  * Base class for {@link org.springframework.web.WebApplicationInitializer}
- * implementations that register a {@link ServletHttpHandlerAdapter} in the servlet context.
+ * implementations that register a {@link ServletHttpHandlerAdapter} in the
+ * servlet context.
  *
- * <p>Concrete implementations are required to implement
- * {@link #createHttpHandler()}, as well as {@link #getServletMappings()},
- * both of which get invoked from {@link #registerHandlerAdapter(ServletContext)}.
- * Further customization can be achieved by overriding
- * {@link #customizeRegistration(ServletRegistration.Dynamic)}.
+ * <p>See {@link AbstractDispatcherHandlerInitializer} if registering a
+ * {@link org.springframework.web.reactive.DispatcherHandler DispatcherHandler}.
  *
  * @author Arjen Poutsma
  * @since 5.0
+ * @see AbstractDispatcherHandlerInitializer
  */
 public abstract class AbstractServletHttpHandlerAdapterInitializer implements WebApplicationInitializer {
 
@@ -67,12 +66,12 @@ public abstract class AbstractServletHttpHandlerAdapterInitializer implements We
 		Assert.hasLength(servletName, "getServletName() must not return empty or null");
 
 		HttpHandler httpHandler = createHttpHandler();
-		Assert.notNull(httpHandler,
-				"createHttpHandler() did not return a HttpHandler for servlet [" + servletName + "]");
+		Assert.notNull(httpHandler, "createHttpHandler() did not return a HttpHandler" +
+				"for servlet [" + servletName + "]");
 
 		ServletHttpHandlerAdapter servlet = createServlet(httpHandler);
-		Assert.notNull(servlet,
-				"createHttpHandler() did not return a ServletHttpHandlerAdapter for servlet [" + servletName + "]");
+		Assert.notNull(servlet, "createHttpHandler() did not return a ServletHttpHandlerAdapter " +
+				"for servlet [" + servletName + "]");
 
 		ServletRegistration.Dynamic registration = servletContext.addServlet(servletName, servlet);
 		Assert.notNull(registration,
@@ -102,8 +101,8 @@ public abstract class AbstractServletHttpHandlerAdapterInitializer implements We
 
 	/**
 	 * Create a {@link ServletHttpHandlerAdapter}  with the specified .
-	 * <p>Default implementation returns a {@code ServletHttpHandlerAdapter} with the provided
-	 * {@code httpHandler}.
+	 * <p>Default implementation returns a {@code ServletHttpHandlerAdapter}
+	 * with the provided {@code httpHandler}.
 	 */
 	protected ServletHttpHandlerAdapter createServlet(HttpHandler httpHandler) {
 		return new ServletHttpHandlerAdapter(httpHandler);