/*
* Copyright 2002-2006 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.portlet.mvc;
import javax.portlet.ActionRequest;
import javax.portlet.ActionResponse;
import javax.portlet.RenderRequest;
import javax.portlet.RenderResponse;
import org.springframework.web.portlet.ModelAndView;
/**
* Base portlet Controller interface, representing a component that receives
* RenderRequest/RenderResponse and ActionRequest/ActionResponse like a
* <code>Portlet</code> but is able to participate in an MVC workflow.
*
* <p>Any implementation of the portlet Controller interface should be a
* <i>reusable, threadsafe</i> 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.</p>
*
* <p><b><a name="workflow">Workflow</a>:</b></p>
*
* <p>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 org.springframework.web.portlet.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 org.springframework.web.portlet.DispatcherPortlet DispatcherPortlet}
* which delegates requests to controllers. These method - and also this interface -
* should preferrably not be implemented by custom controllers <i>directly</i>, since
* abstract controllers also provided by this package already provide a lot of
* functionality for typical use cases in portlet applications. A few examples of
* those controllers:
* {@link AbstractController AbstractController},
* {@link AbstractCommandController AbstractCommandController},
* {@link AbstractFormController AbstractFormController},
* {@link SimpleFormController SimpleFormController}.</p>
*
* <p>So basically any <i>direct</i> 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.</p>
*
* @author William G. Thompson, Jr.
* @author John A. Lewis
* @since 2.0
* @see SimpleControllerHandlerAdapter
* @see AbstractController
* @see AbstractCommandController
* @see AbstractFormController
* @see SimpleFormController
* @see org.springframework.context.ApplicationContextAware
* @see org.springframework.context.ResourceLoaderAware
* @see org.springframework.web.portlet.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</code> 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;
}