Make ErrorPageRegistry first class concern

Create ErrorPageRegistry and ErrorPageRegistrar interfaces that allow
error page registration to be a first class concern.

Prior to this commit ErrorPageFilter needed to implement
ConfigurableEmbeddedServletContainer in order to receive ErrorPage
registrations.

Closes gh-5789

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/web/EmbeddedServletContainerAutoConfiguration.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2015 the original author or authors.
+ * Copyright 2012-2016 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.
@@ -37,12 +37,13 @@ import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnWebApplication;
 import org.springframework.boot.autoconfigure.condition.SearchStrategy;
-import org.springframework.boot.autoconfigure.web.EmbeddedServletContainerAutoConfiguration.EmbeddedServletContainerCustomizerBeanPostProcessorRegistrar;
+import org.springframework.boot.autoconfigure.web.EmbeddedServletContainerAutoConfiguration.BeanPostProcessorsRegistrar;
 import org.springframework.boot.context.embedded.EmbeddedServletContainerCustomizerBeanPostProcessor;
 import org.springframework.boot.context.embedded.EmbeddedServletContainerFactory;
 import org.springframework.boot.context.embedded.jetty.JettyEmbeddedServletContainerFactory;
 import org.springframework.boot.context.embedded.tomcat.TomcatEmbeddedServletContainerFactory;
 import org.springframework.boot.context.embedded.undertow.UndertowEmbeddedServletContainerFactory;
+import org.springframework.boot.web.servlet.ErrorPageRegistrarBeanPostProcessor;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.context.annotation.Import;
@@ -61,7 +62,7 @@ import org.springframework.util.ObjectUtils;
 @AutoConfigureOrder(Ordered.HIGHEST_PRECEDENCE)
 @Configuration
 @ConditionalOnWebApplication
-@Import(EmbeddedServletContainerCustomizerBeanPostProcessorRegistrar.class)
+@Import(BeanPostProcessorsRegistrar.class)
 public class EmbeddedServletContainerAutoConfiguration {
 
 	/**
@@ -114,7 +115,7 @@ public class EmbeddedServletContainerAutoConfiguration {
 	 * Registers a {@link EmbeddedServletContainerCustomizerBeanPostProcessor}. Registered
 	 * via {@link ImportBeanDefinitionRegistrar} for early registration.
 	 */
-	public static class EmbeddedServletContainerCustomizerBeanPostProcessorRegistrar
+	public static class BeanPostProcessorsRegistrar
 			implements ImportBeanDefinitionRegistrar, BeanFactoryAware {
 
 		private ConfigurableListableBeanFactory beanFactory;
@@ -141,6 +142,13 @@ public class EmbeddedServletContainerAutoConfiguration {
 								EmbeddedServletContainerCustomizerBeanPostProcessor.class));
 
 			}
+			if (ObjectUtils.isEmpty(this.beanFactory.getBeanNamesForType(
+					ErrorPageRegistrarBeanPostProcessor.class, true, false))) {
+				registry.registerBeanDefinition("errorPageRegistrarBeanPostProcessor",
+						new RootBeanDefinition(
+								ErrorPageRegistrarBeanPostProcessor.class));
+
+			}
 		}
 
 	}

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/web/ErrorMvcAutoConfiguration.java

@@ -39,9 +39,10 @@ import org.springframework.boot.autoconfigure.condition.ConditionalOnWebApplicat
 import org.springframework.boot.autoconfigure.condition.SearchStrategy;
 import org.springframework.boot.autoconfigure.condition.SpringBootCondition;
 import org.springframework.boot.autoconfigure.template.TemplateAvailabilityProvider;
-import org.springframework.boot.context.embedded.ConfigurableEmbeddedServletContainer;
 import org.springframework.boot.context.embedded.EmbeddedServletContainerCustomizer;
 import org.springframework.boot.web.servlet.ErrorPage;
+import org.springframework.boot.web.servlet.ErrorPageRegistrar;
+import org.springframework.boot.web.servlet.ErrorPageRegistry;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.ConditionContext;
 import org.springframework.context.annotation.Conditional;
@@ -257,8 +258,7 @@ public class ErrorMvcAutoConfiguration {
 	 * {@link EmbeddedServletContainerCustomizer} that configures the container's error
 	 * pages.
 	 */
-	private static class ErrorPageCustomizer
-			implements EmbeddedServletContainerCustomizer, Ordered {
+	private static class ErrorPageCustomizer implements ErrorPageRegistrar, Ordered {
 
 		private final ServerProperties properties;
 
@@ -267,9 +267,10 @@ public class ErrorMvcAutoConfiguration {
 		}
 
 		@Override
-		public void customize(ConfigurableEmbeddedServletContainer container) {
-			container.addErrorPages(new ErrorPage(this.properties.getServletPrefix()
-					+ this.properties.getError().getPath()));
+		public void registerErrorPages(ErrorPageRegistry errorPageRegistry) {
+			ErrorPage errorPage = new ErrorPage(this.properties.getServletPrefix()
+					+ this.properties.getError().getPath());
+			errorPageRegistry.addErrorPages(errorPage);
 		}
 
 		@Override

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/websocket/WebSocketContainerCustomizer.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2015 the original author or authors.
+ * Copyright 2012-2016 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.
@@ -16,13 +16,9 @@
 
 package org.springframework.boot.autoconfigure.websocket;
 
-import org.apache.commons.logging.Log;
-import org.apache.commons.logging.LogFactory;
-
 import org.springframework.boot.context.embedded.ConfigurableEmbeddedServletContainer;
 import org.springframework.boot.context.embedded.EmbeddedServletContainerCustomizer;
 import org.springframework.boot.context.embedded.EmbeddedServletContainerFactory;
-import org.springframework.boot.context.web.NonEmbeddedServletContainerFactory;
 import org.springframework.core.Ordered;
 import org.springframework.core.ResolvableType;
 
@@ -39,8 +35,6 @@ import org.springframework.core.ResolvableType;
 public abstract class WebSocketContainerCustomizer<T extends EmbeddedServletContainerFactory>
 		implements EmbeddedServletContainerCustomizer, Ordered {
 
-	private Log logger = LogFactory.getLog(getClass());
-
 	@Override
 	public int getOrder() {
 		return 0;
@@ -49,12 +43,6 @@ public abstract class WebSocketContainerCustomizer<T extends EmbeddedServletCont
 	@SuppressWarnings("unchecked")
 	@Override
 	public void customize(ConfigurableEmbeddedServletContainer container) {
-		if (container instanceof NonEmbeddedServletContainerFactory) {
-			this.logger.info("NonEmbeddedServletContainerFactory "
-					+ "detected. Websockets support should be native so this "
-					+ "normally is not a problem.");
-			return;
-		}
 		if (getContainerType().isAssignableFrom(container.getClass())) {
 			doCustomize((T) container);
 		}

spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/web/RemappedErrorViewIntegrationTests.java

@@ -21,13 +21,13 @@ import org.junit.runner.RunWith;
 
 import org.springframework.boot.autoconfigure.PropertyPlaceholderAutoConfiguration;
 import org.springframework.boot.builder.SpringApplicationBuilder;
-import org.springframework.boot.context.embedded.ConfigurableEmbeddedServletContainer;
-import org.springframework.boot.context.embedded.EmbeddedServletContainerCustomizer;
 import org.springframework.boot.context.embedded.LocalServerPort;
 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.servlet.ErrorPage;
+import org.springframework.boot.web.servlet.ErrorPageRegistrar;
+import org.springframework.boot.web.servlet.ErrorPageRegistry;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.context.annotation.Import;
 import org.springframework.stereotype.Controller;
@@ -76,7 +76,7 @@ public class RemappedErrorViewIntegrationTests {
 			EmbeddedServletContainerAutoConfiguration.class,
 			DispatcherServletAutoConfiguration.class, ErrorMvcAutoConfiguration.class })
 	@Controller
-	public static class TestConfiguration implements EmbeddedServletContainerCustomizer {
+	public static class TestConfiguration implements ErrorPageRegistrar {
 
 		@RequestMapping("/")
 		public String home() {
@@ -84,8 +84,8 @@ public class RemappedErrorViewIntegrationTests {
 		}
 
 		@Override
-		public void customize(ConfigurableEmbeddedServletContainer container) {
-			container.addErrorPages(new ErrorPage("/spring/error"));
+		public void registerErrorPages(ErrorPageRegistry errorPageRegistry) {
+			errorPageRegistry.addErrorPages(new ErrorPage("/spring/error"));
 		}
 
 		// For manual testing