/*
* Copyright 2002-2009 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;
import javax.portlet.ActionRequest;
import javax.portlet.ActionResponse;
import javax.portlet.EventRequest;
import javax.portlet.EventResponse;
import javax.portlet.RenderRequest;
import javax.portlet.RenderResponse;
import javax.portlet.ResourceRequest;
import javax.portlet.ResourceResponse;
/**
* Portlet MVC framework SPI interface, allowing parameterization of core MVC workflow.
*
* <p>Interface that must be implemented for each handler type to handle a request.
* This interface is used to allow the DispatcherPortlet to be indefinitely
* extensible. The DispatcherPortlet accesses all installed handlers through this
* interface, meaning that it does not contain code specific to any handler type.
*
* <p>Note that a handler can be of type Object. This is to enable handlers from
* other frameworks to be integrated with this framework without custom coding.
*
* <p>This interface is not intended for application developers. It is available
* to handlers who want to develop their own web workflow.
*
* <p>Note: Implementations can implement the Ordered interface to be able to
* specify a sorting order and thus a priority for getting applied by
* DispatcherPortlet. Non-Ordered instances get treated as lowest priority.
*
* @author John A. Lewis
* @since 2.0
* @see org.springframework.web.portlet.mvc.SimpleControllerHandlerAdapter
*/
public interface HandlerAdapter {
/**
* Given a handler instance, return whether or not this HandlerAdapter can
* support it. Typical HandlerAdapters will base the decision on the handler
* type. HandlerAdapters will usually only support one handler type each.
* <p>A typical implementation:
* <p><code>
* return (handler instanceof MyHandler);
* </code>
* @param handler handler object to check
* @return whether or not this object can use the given handler
*/
boolean supports(Object handler);
/**
* Use the given handler to handle this action request.
* The workflow that is required may vary widely.
* @param request current action request
* @param response current action response
* @param handler handler to use. This object must have previously been passed
* to the <code>supports</code> method of this interface, which must have
* returned true.
* @throws Exception in case of errors
* @see javax.portlet.Portlet#processAction
*/
void handleAction(ActionRequest request, ActionResponse response, Object handler) throws Exception;
/**
* Use the given handler to handle this render request.
* The workflow that is required may vary widely.
* @param request current render request
* @param response current render response
* @param handler handler to use. This object must have previously been passed
* to the <code>supports</code> method of this interface, which must have
* returned <code>true</code>.
* @throws Exception in case of errors
* @return ModelAndView object with the name of the view and the required
* model data, or <code>null</code> if the request has been handled directly
* @see javax.portlet.Portlet#render
*/
ModelAndView handleRender(RenderRequest request, RenderResponse response, Object handler) throws Exception;
/**
* Use the given handler to handle this resource request.
* The workflow that is required may vary widely.
* @param request current render request
* @param response current render response
* @param handler handler to use. This object must have previously been passed
* to the <code>supports</code> method of this interface, which must have
* returned <code>true</code>.
* @throws Exception in case of errors
* @return ModelAndView object with the name of the view and the required
* model data, or <code>null</code> if the request has been handled directly
* @see javax.portlet.ResourceServingPortlet#serveResource
*/
ModelAndView handleResource(ResourceRequest request, ResourceResponse response, Object handler) throws Exception;
/**
* Use the given handler to handle this event request.
* The workflow that is required may vary widely.
* @param request current action request
* @param response current action response
* @param handler handler to use. This object must have previously been passed
* to the <code>supports</code> method of this interface, which must have
* returned true.
* @throws Exception in case of errors
* @see javax.portlet.EventPortlet#processEvent
*/
void handleEvent(EventRequest request, EventResponse response, Object handler) throws Exception;
}
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