Spring Framework example source code file (DefaultAnnotationHandlerMapping.java)

This example Spring Framework source code file (DefaultAnnotationHandlerMapping.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Spring Framework tags/keywords

abstractbeandefinition, abstractbeandefinition, class, configurableapplicationcontext, configurableapplicationcontext, defaultannotationhandlermapping, exception, http, httpservletrequest, linkedhashset, reflection, request, requestmapping, requestmapping, response, servlet, set, string, string, util

The Spring Framework DefaultAnnotationHandlerMapping.java source code

/*
 * Copyright 2002-2008 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.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.web.servlet.mvc.annotation;

import java.lang.reflect.Method;
import java.util.HashMap;
import java.util.LinkedHashSet;
import java.util.Map;
import java.util.Set;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;

import org.springframework.beans.factory.config.BeanDefinition;
import org.springframework.beans.factory.support.AbstractBeanDefinition;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.core.annotation.AnnotationUtils;
import org.springframework.stereotype.Controller;
import org.springframework.util.ReflectionUtils;
import org.springframework.util.StringUtils;
import org.springframework.web.HttpRequestMethodNotSupportedException;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.servlet.handler.AbstractDetectingUrlHandlerMapping;

/**
 * Implementation of the {@link org.springframework.web.servlet.HandlerMapping}
 * interface that maps handlers based on HTTP paths expressed through the
 * {@link RequestMapping} annotation at the type or method level.
 *
 * <p>Registered by default in {@link org.springframework.web.servlet.DispatcherServlet}
 * on Java 5+. <b>NOTE: If you define custom HandlerMapping beans in your
 * DispatcherServlet context, you need to add a DefaultAnnotationHandlerMapping bean
 * explicitly, since custom HandlerMapping beans replace the default mapping strategies.
 * Defining a DefaultAnnotationHandlerMapping also allows for registering custom
 * interceptors:
 *
 * <pre class="code">
 * <bean class="org.springframework.web.servlet.mvc.annotation.DefaultAnnotationHandlerMapping">
 *   <property name="interceptors">
 *     ...
 *   </property>
 * </bean></pre>
 *
 * Annotated controllers are usually marked with the {@link Controller} stereotype
 * at the type level. This is not strictly necessary when {@link RequestMapping} is
 * applied at the type level (since such a handler usually implements the
 * {@link org.springframework.web.servlet.mvc.Controller} interface). However,
 * {@link Controller} is required for detecting {@link RequestMapping} annotations
 * at the method level if {@link RequestMapping} is not present at the type level.
 *
 * <p>NOTE: Method-level mappings are only allowed to narrow the mapping
 * expressed at the class level (if any). HTTP paths need to uniquely map onto
 * specific handler beans, with any given HTTP path only allowed to be mapped
 * onto one specific handler bean (not spread across multiple handler beans).
 * It is strongly recommended to co-locate related handler methods into the same bean.
 *
 * <p>The {@link AnnotationMethodHandlerAdapter} is responsible for processing
 * annotated handler methods, as mapped by this HandlerMapping. For
 * {@link RequestMapping} at the type level, specific HandlerAdapters such as
 * {@link org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter} apply.
 *
 * @author Juergen Hoeller
 * @author Arjen Poutsma
 * @since 2.5
 * @see RequestMapping
 * @see AnnotationMethodHandlerAdapter
 */
public class DefaultAnnotationHandlerMapping extends AbstractDetectingUrlHandlerMapping {

	private boolean useDefaultSuffixPattern = true;

	private final Map<Class, RequestMapping> cachedMappings = new HashMap();


	/**
	 * Set whether to register paths using the default suffix pattern as well:
	 * i.e. whether "/users" should be registered as "/users.*" too.
	 * <p>Default is "true". Turn this convention off if you intend to interpret
	 * your <code>@RequestMapping paths strictly.
	 * <p>Note that paths which include a ".xxx" suffix already will not be
	 * transformed using the default suffix pattern in any case.
	 */
	public void setUseDefaultSuffixPattern(boolean useDefaultSuffixPattern) {
		this.useDefaultSuffixPattern = useDefaultSuffixPattern;
	}


	/**
	 * Checks for presence of the {@link org.springframework.web.bind.annotation.RequestMapping}
	 * annotation on the handler class and on any of its methods.
	 */
	protected String[] determineUrlsForHandler(String beanName) {
		ApplicationContext context = getApplicationContext();
		Class<?> handlerType = context.getType(beanName);
		RequestMapping mapping = AnnotationUtils.findAnnotation(handlerType, RequestMapping.class);

		if (mapping == null && context instanceof ConfigurableApplicationContext &&
				context.containsBeanDefinition(beanName)) {
			ConfigurableApplicationContext cac = (ConfigurableApplicationContext) context;
			BeanDefinition bd = cac.getBeanFactory().getMergedBeanDefinition(beanName);
			if (bd instanceof AbstractBeanDefinition) {
				AbstractBeanDefinition abd = (AbstractBeanDefinition) bd;
				if (abd.hasBeanClass()) {
					Class<?> beanClass = abd.getBeanClass();
					mapping = AnnotationUtils.findAnnotation(beanClass, RequestMapping.class);
				}
			}
		}

		if (mapping != null) {
			// @RequestMapping found at type level
			this.cachedMappings.put(handlerType, mapping);
			Set<String> urls = new LinkedHashSet();
			String[] paths = mapping.value();
			if (paths.length > 0) {
				// @RequestMapping specifies paths at type level
				for (String path : paths) {
					addUrlsForPath(urls, path);
				}
				return StringUtils.toStringArray(urls);
			}
			else {
				// actual paths specified by @RequestMapping at method level
				return determineUrlsForHandlerMethods(handlerType);
			}
		}
		else if (AnnotationUtils.findAnnotation(handlerType, Controller.class) != null) {
			// @RequestMapping to be introspected at method level
			return determineUrlsForHandlerMethods(handlerType);
		}
		else {
			return null;
		}
	}

	/**
	 * Derive URL mappings from the handler's method-level mappings.
	 * @param handlerType the handler type to introspect
	 * @return the array of mapped URLs
	 */
	protected String[] determineUrlsForHandlerMethods(Class<?> handlerType) {
		final Set<String> urls = new LinkedHashSet();
		ReflectionUtils.doWithMethods(handlerType, new ReflectionUtils.MethodCallback() {
			public void doWith(Method method) {
				RequestMapping mapping = method.getAnnotation(RequestMapping.class);
				if (mapping != null) {
					String[] mappedPaths = mapping.value();
					for (int i = 0; i < mappedPaths.length; i++) {
						addUrlsForPath(urls, mappedPaths[i]);
					}
				}
			}
		});
		return StringUtils.toStringArray(urls);
	}

	/**
	 * Add URLs and/or URL patterns for the given path.
	 * @param urls the Set of URLs for the current bean
	 * @param path the currently introspected path
	 */
	protected void addUrlsForPath(Set<String> urls, String path) {
		urls.add(path);
		if (this.useDefaultSuffixPattern && path.indexOf('.') == -1) {
			urls.add(path + ".*");
		}
	}


	/**
	 * Validate the given annotated handler against the current request.
	 * @see #validateMapping
	 */
	protected void validateHandler(Object handler, HttpServletRequest request) throws Exception {
		RequestMapping mapping = this.cachedMappings.get(handler.getClass());
		if (mapping == null) {
			mapping = AnnotationUtils.findAnnotation(handler.getClass(), RequestMapping.class);
		}
		if (mapping != null) {
			validateMapping(mapping, request);
		}
	}

	/**
	 * Validate the given type-level mapping metadata against the current request,
	 * checking HTTP request method and parameter conditions.
	 * @param mapping the mapping metadata to validate
	 * @param request current HTTP request
	 * @throws Exception if validation failed
	 */
	protected void validateMapping(RequestMapping mapping, HttpServletRequest request) throws Exception {
		RequestMethod[] mappedMethods = mapping.method();
		if (!ServletAnnotationMappingUtils.checkRequestMethod(mappedMethods, request)) {
			String[] supportedMethods = new String[mappedMethods.length];
			for (int i = 0; i < mappedMethods.length; i++) {
				supportedMethods[i] = mappedMethods[i].name();
			}
			throw new HttpRequestMethodNotSupportedException(request.getMethod(), supportedMethods);
		}

		String[] mappedParams = mapping.params();
		if (!ServletAnnotationMappingUtils.checkParameters(mappedParams, request)) {
			throw new ServletException("Parameter conditions {" +
					StringUtils.arrayToDelimitedString(mappedParams, ", ") +
					"} not met for request parameters: " + request.getParameterMap());
		}
	}

}