org.springframework.web.servlet.mvc.method.annotation.ViewMethodReturnValueHandler Maven / Gradle / Ivy
/*
* Copyright 2002-2019 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
*
* https://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.mvc.method.annotation;
import org.springframework.core.MethodParameter;
import org.springframework.lang.Nullable;
import org.springframework.web.context.request.NativeWebRequest;
import org.springframework.web.method.support.HandlerMethodReturnValueHandler;
import org.springframework.web.method.support.ModelAndViewContainer;
import org.springframework.web.servlet.RequestToViewNameTranslator;
import org.springframework.web.servlet.SmartView;
import org.springframework.web.servlet.View;
/**
* Handles return values that are of type {@link View}.
*
* A {@code null} return value is left as-is leaving it to the configured
* {@link RequestToViewNameTranslator} to select a view name by convention.
*
*
A {@link View} return type has a set purpose. Therefore this handler
* should be configured ahead of handlers that support any return value type
* annotated with {@code @ModelAttribute} or {@code @ResponseBody} to ensure
* they don't take over.
*
* @author Rossen Stoyanchev
* @since 3.1
*/
public class ViewMethodReturnValueHandler implements HandlerMethodReturnValueHandler {
@Override
public boolean supportsReturnType(MethodParameter returnType) {
return View.class.isAssignableFrom(returnType.getParameterType());
}
@Override
public void handleReturnValue(@Nullable Object returnValue, MethodParameter returnType,
ModelAndViewContainer mavContainer, NativeWebRequest webRequest) throws Exception {
if (returnValue instanceof View) {
View view = (View) returnValue;
mavContainer.setView(view);
if (view instanceof SmartView && ((SmartView) view).isRedirectView()) {
mavContainer.setRedirectModelScenario(true);
}
}
else if (returnValue != null) {
// should not happen
throw new UnsupportedOperationException("Unexpected return type: " +
returnType.getParameterType().getName() + " in method: " + returnType.getMethod());
}
}
}