HandlerMappingIntrospector is a bean

Author: rstoyanchev

spring-webmvc/src/main/java/org/springframework/web/servlet/config/MvcNamespaceUtils.java

@@ -29,6 +29,7 @@
 import org.springframework.util.PathMatcher;
 import org.springframework.web.cors.CorsConfiguration;
 import org.springframework.web.servlet.handler.BeanNameUrlHandlerMapping;
+import org.springframework.web.servlet.handler.HandlerMappingIntrospector;
 import org.springframework.web.servlet.mvc.HttpRequestHandlerAdapter;
 import org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter;
 import org.springframework.web.util.UrlPathHelper;
@@ -57,11 +58,14 @@ abstract class MvcNamespaceUtils {
 
 	private static final String CORS_CONFIGURATION_BEAN_NAME = "mvcCorsConfigurations";
 
+	private static final String HANDLER_MAPPING_INTROSPECTOR_BEAN_NAME = "mvcHandlerMappingIntrospector";
+
 
 	public static void registerDefaultComponents(ParserContext parserContext, @Nullable Object source) {
 		registerBeanNameUrlHandlerMapping(parserContext, source);
 		registerHttpRequestHandlerAdapter(parserContext, source);
 		registerSimpleControllerHandlerAdapter(parserContext, source);
+		registerHandlerMappingIntrospector(parserContext, source);
 	}
 
 	/**
@@ -186,6 +190,21 @@ else if (corsConfigurations != null) {
 		return new RuntimeBeanReference(CORS_CONFIGURATION_BEAN_NAME);
 	}
 
+	/**
+	 * Registers  an {@link HandlerMappingIntrospector} under a well-known name
+	 * unless already registered.
+	 */
+	private static void registerHandlerMappingIntrospector(ParserContext parserContext, @Nullable Object source) {
+		if (!parserContext.getRegistry().containsBeanDefinition(HANDLER_MAPPING_INTROSPECTOR_BEAN_NAME)){
+			RootBeanDefinition beanDef = new RootBeanDefinition(HandlerMappingIntrospector.class);
+			beanDef.setSource(source);
+			beanDef.setRole(BeanDefinition.ROLE_INFRASTRUCTURE);
+			beanDef.setLazyInit(true);
+			parserContext.getRegistry().registerBeanDefinition(HANDLER_MAPPING_INTROSPECTOR_BEAN_NAME, beanDef);
+			parserContext.registerComponent(new BeanComponentDefinition(beanDef, HANDLER_MAPPING_INTROSPECTOR_BEAN_NAME));
+		}
+	}
+
 	/**
 	 * Find the {@code ContentNegotiationManager} bean created by or registered
 	 * with the {@code annotation-driven} element.

spring-webmvc/src/main/java/org/springframework/web/servlet/config/annotation/WebMvcConfigurationSupport.java

@@ -32,6 +32,7 @@
 import org.springframework.context.ApplicationContextAware;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
+import org.springframework.context.annotation.Lazy;
 import org.springframework.core.convert.converter.Converter;
 import org.springframework.format.Formatter;
 import org.springframework.format.FormatterRegistry;
@@ -82,6 +83,7 @@
 import org.springframework.web.servlet.handler.BeanNameUrlHandlerMapping;
 import org.springframework.web.servlet.handler.ConversionServiceExposingInterceptor;
 import org.springframework.web.servlet.handler.HandlerExceptionResolverComposite;
+import org.springframework.web.servlet.handler.HandlerMappingIntrospector;
 import org.springframework.web.servlet.mvc.Controller;
 import org.springframework.web.servlet.mvc.HttpRequestHandlerAdapter;
 import org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter;
@@ -1022,6 +1024,12 @@ protected final Map<String, CorsConfiguration> getCorsConfigurations() {
 	protected void addCorsMappings(CorsRegistry registry) {
 	}
 
+	@Bean @Lazy
+	public HandlerMappingIntrospector mvcHandlerMappingIntrospector() {
+		return new HandlerMappingIntrospector();
+	}
+
+
 
 	private static final class EmptyHandlerMapping extends AbstractHandlerMapping {
 

spring-webmvc/src/main/java/org/springframework/web/servlet/handler/HandlerMappingIntrospector.java

@@ -18,20 +18,23 @@
 
 import java.io.IOException;
 import java.util.ArrayList;
+import java.util.Collections;
 import java.util.List;
 import java.util.Map;
 import java.util.Properties;
-
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletRequestWrapper;
 
 import org.springframework.beans.factory.BeanFactoryUtils;
+import org.springframework.beans.factory.InitializingBean;
 import org.springframework.context.ApplicationContext;
+import org.springframework.context.ApplicationContextAware;
 import org.springframework.core.annotation.AnnotationAwareOrderComparator;
 import org.springframework.core.io.ClassPathResource;
 import org.springframework.core.io.Resource;
 import org.springframework.core.io.support.PropertiesLoaderUtils;
 import org.springframework.lang.Nullable;
+import org.springframework.util.Assert;
 import org.springframework.util.ClassUtils;
 import org.springframework.util.StringUtils;
 import org.springframework.web.cors.CorsConfiguration;
@@ -56,33 +59,66 @@
  * @author Rossen Stoyanchev
  * @since 4.3.1
  */
-public class HandlerMappingIntrospector implements CorsConfigurationSource {
+public class HandlerMappingIntrospector
+		implements CorsConfigurationSource, ApplicationContextAware, InitializingBean {
+
+	@Nullable
+	private ApplicationContext applicationContext;
+
+	@Nullable
+	private List<HandlerMapping> handlerMappings;
 
-	private final List<HandlerMapping> handlerMappings;
 
+	/**
+	 * Constructor for use with {@link ApplicationContextAware}.
+	 */
+	public HandlerMappingIntrospector() {
+	}
 
 	/**
 	 * Constructor that detects the configured {@code HandlerMapping}s in the
 	 * given {@code ApplicationContext} or falls back on
 	 * "DispatcherServlet.properties" like the {@code DispatcherServlet}.
 	 */
+	@Deprecated
 	public HandlerMappingIntrospector(ApplicationContext context) {
 		this.handlerMappings = initHandlerMappings(context);
 	}
 
 
-	private static List<HandlerMapping> initHandlerMappings(ApplicationContext context) {
+	/**
+	 * Return the configured HandlerMapping's.
+	 */
+	public List<HandlerMapping> getHandlerMappings() {
+		return this.handlerMappings;
+	}
+
+
+	@Override
+	public void setApplicationContext(ApplicationContext applicationContext) {
+		this.applicationContext = applicationContext;
+	}
+
+	@Override
+	public void afterPropertiesSet() {
+		if (this.handlerMappings == null) {
+			Assert.notNull(this.applicationContext, "No ApplicationContext");
+			this.handlerMappings = initHandlerMappings(this.applicationContext);
+		}
+	}
+
+	private static List<HandlerMapping> initHandlerMappings(ApplicationContext applicationContext) {
 		Map<String, HandlerMapping> beans = BeanFactoryUtils.beansOfTypeIncludingAncestors(
-				context, HandlerMapping.class, true, false);
+				applicationContext, HandlerMapping.class, true, false);
 		if (!beans.isEmpty()) {
 			List<HandlerMapping> mappings = new ArrayList<>(beans.values());
 			AnnotationAwareOrderComparator.sort(mappings);
-			return mappings;
+			return Collections.unmodifiableList(mappings);
 		}
-		return initDefaultHandlerMappings(context);
+		return Collections.unmodifiableList(initFallback(applicationContext));
 	}
 
-	private static List<HandlerMapping> initDefaultHandlerMappings(ApplicationContext context) {
+	private static List<HandlerMapping> initFallback(ApplicationContext applicationContext) {
 		Properties props;
 		String path = "DispatcherServlet.properties";
 		try {
@@ -99,7 +135,7 @@ private static List<HandlerMapping> initDefaultHandlerMappings(ApplicationContex
 		for (String name : names) {
 			try {
 				Class<?> clazz = ClassUtils.forName(name, DispatcherServlet.class.getClassLoader());
-				Object mapping = context.getAutowireCapableBeanFactory().createBean(clazz);
+				Object mapping = applicationContext.getAutowireCapableBeanFactory().createBean(clazz);
 				result.add((HandlerMapping) mapping);
 			}
 			catch (ClassNotFoundException ex) {
@@ -110,13 +146,6 @@ private static List<HandlerMapping> initDefaultHandlerMappings(ApplicationContex
 	}
 
 
-	/**
-	 * Return the configured HandlerMapping's.
-	 */
-	public List<HandlerMapping> getHandlerMappings() {
-		return this.handlerMappings;
-	}
-
 	/**
 	 * Find the {@link HandlerMapping} that would handle the given request and
 	 * return it as a {@link MatchableHandlerMapping} that can be used to test
@@ -129,6 +158,7 @@ public List<HandlerMapping> getHandlerMappings() {
 	 */
 	@Nullable
 	public MatchableHandlerMapping getMatchableHandlerMapping(HttpServletRequest request) throws Exception {
+		Assert.notNull(this.handlerMappings, "Handler mappings not initialized");
 		HttpServletRequest wrapper = new RequestAttributeChangeIgnoringWrapper(request);
 		for (HandlerMapping handlerMapping : this.handlerMappings) {
 			Object handler = handlerMapping.getHandler(wrapper);
@@ -146,6 +176,7 @@ public MatchableHandlerMapping getMatchableHandlerMapping(HttpServletRequest req
 	@Override
 	@Nullable
 	public CorsConfiguration getCorsConfiguration(HttpServletRequest request) {
+		Assert.notNull(this.handlerMappings, "Handler mappings not initialized");
 		HttpServletRequest wrapper = new RequestAttributeChangeIgnoringWrapper(request);
 		for (HandlerMapping handlerMapping : this.handlerMappings) {
 			HandlerExecutionChain handler = null;