Restructure embedded web server packages

Rework `org.springframework.boot.context.embedded` to relocate classes
to `org.springframework.boot.web`. Packages are now organized around
the following areas:

Packages for shared concerns, for example the `WebServer` interface
to start/stop a server and the common configuration elements:
- org.springframework.boot.web.context
- org.springframework.boot.web.server

Servlet specific packages:
- org.springframework.boot.web.servlet.server
- org.springframework.boot.web.servlet.context
- org.springframework.boot.web.servlet.filter

Reactive specific packages:
- org.springframework.boot.web.reactive.context
- org.springframework.boot.web.reactive.server

Embedded server implementations (both reactive and servlet):
- org.springframework.boot.web.embedded

In addition:

- Rename `EmbeddedServletContainerFactory` to `ServletWebServerFactory`
  to align with the `ReactiveWebServerFactory`.
- Rename `EmbeddedWebApplicationContext` to
  `ServletWebServerApplicationContext` and
- Rename `EmbeddedReactiveWebApplicationContext` to
  `ReactiveWebServerApplicationContext`.
- Add checkstyle rules to restrict imports.
- Fixup all affected code to use the correct imports and local names.

Fixes gh-8532

spring-boot-devtools/src/test/java/org/springframework/boot/devtools/autoconfigure/LocalDevToolsAutoConfigurationTests.java

@@ -33,10 +33,8 @@ import org.thymeleaf.spring5.templateresolver.SpringResourceTemplateResolver;
 import org.springframework.beans.factory.NoSuchBeanDefinitionException;
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.thymeleaf.ThymeleafAutoConfiguration;
-import org.springframework.boot.autoconfigure.web.EmbeddedServletContainerAutoConfiguration;
 import org.springframework.boot.autoconfigure.web.ResourceProperties;
-import org.springframework.boot.context.embedded.EmbeddedWebApplicationContext;
-import org.springframework.boot.context.embedded.tomcat.TomcatEmbeddedServletContainer;
+import org.springframework.boot.autoconfigure.web.ServletWebServerFactoryAutoConfiguration;
 import org.springframework.boot.devtools.classpath.ClassPathChangedEvent;
 import org.springframework.boot.devtools.classpath.ClassPathFileSystemWatcher;
 import org.springframework.boot.devtools.filewatch.ChangedFiles;
@@ -45,6 +43,8 @@ import org.springframework.boot.devtools.restart.FailureHandler;
 import org.springframework.boot.devtools.restart.MockRestartInitializer;
 import org.springframework.boot.devtools.restart.MockRestarter;
 import org.springframework.boot.devtools.restart.Restarter;
+import org.springframework.boot.web.embedded.tomcat.TomcatWebServer;
+import org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext;
 import org.springframework.context.ConfigurableApplicationContext;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
@@ -243,8 +243,8 @@ public class LocalDevToolsAutoConfigurationTests {
 	@Test
 	public void devToolsSwitchesJspServletToDevelopmentMode() {
 		this.context = initializeAndRun(Config.class);
-		TomcatEmbeddedServletContainer tomcatContainer = (TomcatEmbeddedServletContainer) ((EmbeddedWebApplicationContext) this.context)
-				.getEmbeddedWebServer();
+		TomcatWebServer tomcatContainer = (TomcatWebServer) ((ServletWebServerApplicationContext) this.context)
+				.getWebServer();
 		Container context = tomcatContainer.getTomcat().getHost().findChildren()[0];
 		StandardWrapper jspServletWrapper = (StandardWrapper) context.findChild("jsp");
 		EmbeddedServletOptions options = (EmbeddedServletOptions) ReflectionTestUtils
@@ -277,14 +277,14 @@ public class LocalDevToolsAutoConfigurationTests {
 	}
 
 	@Configuration
-	@Import({ EmbeddedServletContainerAutoConfiguration.class,
+	@Import({ ServletWebServerFactoryAutoConfiguration.class,
 			LocalDevToolsAutoConfiguration.class, ThymeleafAutoConfiguration.class })
 	public static class Config {
 
 	}
 
 	@Configuration
-	@Import({ EmbeddedServletContainerAutoConfiguration.class,
+	@Import({ ServletWebServerFactoryAutoConfiguration.class,
 			LocalDevToolsAutoConfiguration.class, ThymeleafAutoConfiguration.class })
 	public static class ConfigWithMockLiveReload {
 
@@ -296,7 +296,7 @@ public class LocalDevToolsAutoConfigurationTests {
 	}
 
 	@Configuration
-	@Import({ EmbeddedServletContainerAutoConfiguration.class,
+	@Import({ ServletWebServerFactoryAutoConfiguration.class,
 			LocalDevToolsAutoConfiguration.class, ResourceProperties.class })
 	public static class WebResourcesConfig {
 

spring-boot-devtools/src/test/java/org/springframework/boot/devtools/integrationtest/HttpTunnelIntegrationTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2016 the original author or authors.
+ * Copyright 2012-2017 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.
@@ -23,8 +23,6 @@ import org.junit.Test;
 import org.junit.runner.RunWith;
 
 import org.springframework.beans.factory.annotation.Autowired;
-import org.springframework.boot.context.embedded.EmbeddedServletContainerFactory;
-import org.springframework.boot.context.embedded.tomcat.TomcatEmbeddedServletContainerFactory;
 import org.springframework.boot.devtools.remote.server.AccessManager;
 import org.springframework.boot.devtools.remote.server.Dispatcher;
 import org.springframework.boot.devtools.remote.server.DispatcherFilter;
@@ -42,6 +40,8 @@ import org.springframework.boot.devtools.tunnel.server.TargetServerConnection;
 import org.springframework.boot.test.context.SpringBootTest;
 import org.springframework.boot.test.context.SpringBootTest.WebEnvironment;
 import org.springframework.boot.test.web.client.TestRestTemplate;
+import org.springframework.boot.web.embedded.tomcat.TomcatServletWebServerFactory;
+import org.springframework.boot.web.servlet.server.ServletWebServerFactory;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.http.HttpStatus;
@@ -95,8 +95,8 @@ public class HttpTunnelIntegrationTests {
 		private int httpServerPort = SocketUtils.findAvailableTcpPort();
 
 		@Bean
-		public EmbeddedServletContainerFactory container() {
-			return new TomcatEmbeddedServletContainerFactory(this.httpServerPort);
+		public ServletWebServerFactory container() {
+			return new TomcatServletWebServerFactory(this.httpServerPort);
 		}
 
 		@Bean

spring-boot-devtools/src/test/java/org/springframework/boot/devtools/remote/client/RemoteClientConfigurationTests.java

@@ -28,8 +28,6 @@ import org.junit.rules.ExpectedException;
 
 import org.springframework.beans.factory.BeanCreationException;
 import org.springframework.beans.factory.NoSuchBeanDefinitionException;
-import org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext;
-import org.springframework.boot.context.embedded.tomcat.TomcatEmbeddedServletContainerFactory;
 import org.springframework.boot.devtools.autoconfigure.OptionalLiveReloadServer;
 import org.springframework.boot.devtools.classpath.ClassPathChangedEvent;
 import org.springframework.boot.devtools.classpath.ClassPathFileSystemWatcher;
@@ -43,6 +41,8 @@ import org.springframework.boot.devtools.restart.RestartScopeInitializer;
 import org.springframework.boot.devtools.tunnel.client.TunnelClient;
 import org.springframework.boot.test.rule.OutputCapture;
 import org.springframework.boot.test.util.EnvironmentTestUtils;
+import org.springframework.boot.web.embedded.tomcat.TomcatServletWebServerFactory;
+import org.springframework.boot.web.servlet.context.AnnotationConfigServletWebServerApplicationContext;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.http.server.ServerHttpRequest;
@@ -71,7 +71,7 @@ public class RemoteClientConfigurationTests {
 	@Rule
 	public ExpectedException thrown = ExpectedException.none();
 
-	private AnnotationConfigEmbeddedWebApplicationContext context;
+	private AnnotationConfigServletWebServerApplicationContext context;
 
 	private static int remotePort = SocketUtils.findAvailableTcpPort();
 
@@ -149,7 +149,7 @@ public class RemoteClientConfigurationTests {
 	}
 
 	private void configure(String remoteUrl, boolean setSecret, String... pairs) {
-		this.context = new AnnotationConfigEmbeddedWebApplicationContext();
+		this.context = new AnnotationConfigServletWebServerApplicationContext();
 		new RestartScopeInitializer().initialize(this.context);
 		this.context.register(Config.class, RemoteClientConfiguration.class);
 		String remoteUrlProperty = "remoteUrl:" + remoteUrl + ":"
@@ -167,8 +167,8 @@ public class RemoteClientConfigurationTests {
 	static class Config {
 
 		@Bean
-		public TomcatEmbeddedServletContainerFactory tomcat() {
-			return new TomcatEmbeddedServletContainerFactory(remotePort);
+		public TomcatServletWebServerFactory tomcat() {
+			return new TomcatServletWebServerFactory(remotePort);
 		}
 
 		@Bean