/*
 * Copyright 2002-2010 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.config;

import org.springframework.beans.factory.config.BeanDefinition;
import org.springframework.beans.factory.parsing.BeanComponentDefinition;
import org.springframework.beans.factory.support.RootBeanDefinition;
import org.springframework.beans.factory.xml.ParserContext;
import org.springframework.web.servlet.handler.BeanNameUrlHandlerMapping;
import org.springframework.web.servlet.mvc.HttpRequestHandlerAdapter;
import org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter;

/**
 * Convenience methods for use in MVC namespace BeanDefinitionParsers.
 * 
 * @author Rossen Stoyanchev
 * @since 3.1
 */
abstract class MvcNamespaceUtils {

	private static final String BEAN_NAME_URL_HANDLER_MAPPING_BEAN_NAME = 
			BeanNameUrlHandlerMapping.class.getName();

	private static final String SIMPLE_CONTROLLER_HANDLER_ADAPTER_BEAN_NAME = 
			SimpleControllerHandlerAdapter.class.getName();

	private static final String HTTP_REQUEST_HANDLER_ADAPTER_BEAN_NAME = 
			HttpRequestHandlerAdapter.class.getName();

	public static void registerDefaultComponents(ParserContext parserContext, Object source) {
		registerBeanNameUrlHandlerMapping(parserContext, source);
		registerHttpRequestHandlerAdapter(parserContext, source);
		registerSimpleControllerHandlerAdapter(parserContext, source);
	}

	/**
	 * Registers  an {@link HttpRequestHandlerAdapter} under a well-known 
	 * name unless already registered.
	 */
	private static void registerBeanNameUrlHandlerMapping(ParserContext parserContext, Object source) {
		if (!parserContext.getRegistry().containsBeanDefinition(BEAN_NAME_URL_HANDLER_MAPPING_BEAN_NAME)){
			RootBeanDefinition beanNameMappingDef = new RootBeanDefinition(BeanNameUrlHandlerMapping.class);
			beanNameMappingDef.setSource(source);
			beanNameMappingDef.setRole(BeanDefinition.ROLE_INFRASTRUCTURE);
			beanNameMappingDef.getPropertyValues().add("order", 2);	// consistent with WebMvcConfigurationSupport
			parserContext.getRegistry().registerBeanDefinition(BEAN_NAME_URL_HANDLER_MAPPING_BEAN_NAME, beanNameMappingDef);
			parserContext.registerComponent(new BeanComponentDefinition(beanNameMappingDef, BEAN_NAME_URL_HANDLER_MAPPING_BEAN_NAME));
		}
	}

	/**
	 * Registers  an {@link HttpRequestHandlerAdapter} under a well-known 
	 * name unless already registered.
	 */
	private static void registerHttpRequestHandlerAdapter(ParserContext parserContext, Object source) {
		if (!parserContext.getRegistry().containsBeanDefinition(HTTP_REQUEST_HANDLER_ADAPTER_BEAN_NAME)) {
			RootBeanDefinition handlerAdapterDef = new RootBeanDefinition(HttpRequestHandlerAdapter.class);
			handlerAdapterDef.setSource(source);
			handlerAdapterDef.setRole(BeanDefinition.ROLE_INFRASTRUCTURE);
			parserContext.getRegistry().registerBeanDefinition(HTTP_REQUEST_HANDLER_ADAPTER_BEAN_NAME, handlerAdapterDef);
			parserContext.registerComponent(new BeanComponentDefinition(handlerAdapterDef, HTTP_REQUEST_HANDLER_ADAPTER_BEAN_NAME));
		}
	}
	
	/**
	 * Registers a {@link SimpleControllerHandlerAdapter} under a well-known 
	 * name unless already registered.
	 */
	private static void registerSimpleControllerHandlerAdapter(ParserContext parserContext, Object source) {
		if (!parserContext.getRegistry().containsBeanDefinition(SIMPLE_CONTROLLER_HANDLER_ADAPTER_BEAN_NAME)) {
			RootBeanDefinition handlerAdapterDef = new RootBeanDefinition(SimpleControllerHandlerAdapter.class);
			handlerAdapterDef.setSource(source);
			handlerAdapterDef.setRole(BeanDefinition.ROLE_INFRASTRUCTURE);
			parserContext.getRegistry().registerBeanDefinition(SIMPLE_CONTROLLER_HANDLER_ADAPTER_BEAN_NAME, handlerAdapterDef);
			parserContext.registerComponent(new BeanComponentDefinition(handlerAdapterDef, SIMPLE_CONTROLLER_HANDLER_ADAPTER_BEAN_NAME));
		}
	}

}
