/*
* Copyright 2002-2011 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.handler;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.springframework.web.method.HandlerMethod;
import org.springframework.web.servlet.ModelAndView;
/**
* Abstract base class for {@link org.springframework.web.servlet.HandlerExceptionResolver HandlerExceptionResolver}
* implementations that support handling exceptions from {@link HandlerMethod}s rather than handlers.
*
* @author Rossen Stoyanchev
* @since 3.1
*/
public class AbstractHandlerMethodExceptionResolver extends AbstractHandlerExceptionResolver {
/**
* Checks if the handler is a {@link HandlerMethod} instance and performs the check against the bean
* instance it contains. If the provided handler is not an instance of {@link HandlerMethod},
* {@code false} is returned instead.
*/
@Override
protected boolean shouldApplyTo(HttpServletRequest request, Object handler) {
if (handler == null) {
return super.shouldApplyTo(request, handler);
}
else if (handler instanceof HandlerMethod) {
HandlerMethod handlerMethod = (HandlerMethod) handler;
handler = handlerMethod.getBean();
return super.shouldApplyTo(request, handler);
}
else {
return false;
}
}
@Override
protected final ModelAndView doResolveException(HttpServletRequest request,
HttpServletResponse response,
Object handler,
Exception ex) {
return doResolveHandlerMethodException(request, response, (HandlerMethod) handler, ex);
}
/**
* Actually resolve the given exception that got thrown during on handler execution,
* returning a ModelAndView that represents a specific error page if appropriate.
* <p>May be overridden in subclasses, in order to apply specific exception checks.
* Note that this template method will be invoked <i>after</i> checking whether this
* resolved applies ("mappedHandlers" etc), so an implementation may simply proceed
* with its actual exception handling.
* @param request current HTTP request
* @param response current HTTP response
* @param handlerMethod the executed handler method, or <code>null</code> if none chosen at the time
* of the exception (for example, if multipart resolution failed)
* @param ex the exception that got thrown during handler execution
* @return a corresponding ModelAndView to forward to, or <code>null</code> for default processing
*/
protected ModelAndView doResolveHandlerMethodException(HttpServletRequest request,
HttpServletResponse response,
HandlerMethod handlerMethod,
Exception ex) {
return null;
}
}