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PortletMVC4Spring Framework
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/**
 * Copyright (c) 2000-2020 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 com.liferay.portletmvc4spring.mvc;

import javax.portlet.ActionRequest;
import javax.portlet.ActionResponse;
import javax.portlet.RenderRequest;
import javax.portlet.RenderResponse;

import com.liferay.portletmvc4spring.ModelAndView;


/**
 * Base portlet Controller interface, representing a component that receives RenderRequest/RenderResponse and
 * ActionRequest/ActionResponse like a {@code Portlet} but is able to participate in an MVC workflow.
 *
 * Any implementation of the portlet Controller interface should be a reusable, threadsafe class, capable of
 * handling multiple portlet requests throughout the lifecycle of an application. To be able to configure Controller(s)
 * in an easy way, Controllers are usually JavaBeans.
 *
 * Workflow:
 *
 * After the DispatcherPortlet has received a request and has done its work to resolve locales, themes and suchlike,
 * it tries to resolve a Controller to handle that request, using a {@link com.liferay.portletmvc4spring.HandlerMapping
 * HandlerMapping}. When a Controller has been found, the {@link #handleRenderRequest handleRenderRequest} or {@link
 * #handleActionRequest handleActionRequest} method will be invoked, which is responsible for handling the actual
 * request and - if applicable - returning an appropriate ModelAndView. So actually, these method are the main
 * entrypoint for the {@link com.liferay.portletmvc4spring.DispatcherPortlet DispatcherPortlet} which delegates requests
 * to controllers.
 *
 * So basically any direct implementation of the Controller interface just handles
 * RenderRequests/ActionRequests and should return a ModelAndView, to be further used by the DispatcherPortlet. Any
 * additional functionality such as optional validation, form handling, etc should be obtained through extending one of
 * the abstract controller classes mentioned above.
 *
 * @author  William G. Thompson, Jr.
 * @author  John A. Lewis
 * @since   2.0
 * @see     ResourceAwareController
 * @see     EventAwareController
 * @see     SimpleControllerHandlerAdapter
 * @see     AbstractController
 * @see     com.liferay.portletmvc4spring.context.PortletContextAware
 */
public interface Controller {

	/**
	 * Process the action request. There is nothing to return.
	 *
	 * @param   request   current portlet action request
	 * @param   response  current portlet action response
	 *
	 * @throws  Exception  in case of errors
	 */
	void handleActionRequest(ActionRequest request, ActionResponse response) throws Exception;

	/**
	 * Process the render request and return a ModelAndView object which the DispatcherPortlet will render. A {@code
	 * null} return value is not an error: It indicates that this object completed request processing itself, thus there
	 * is no ModelAndView to render.
	 *
	 * @param   request   current portlet render request
	 * @param   response  current portlet render response
	 *
	 * @return  a ModelAndView to render, or null if handled directly
	 *
	 * @throws  Exception  in case of errors
	 */
	ModelAndView handleRenderRequest(RenderRequest request, RenderResponse response) throws Exception;

}