org.springframework.web.servlet.view.BeanNameViewResolver Maven / Gradle / Ivy
/*
* Copyright 2002-2020 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
*
* 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.view;
import java.util.Locale;
import org.springframework.beans.BeansException;
import org.springframework.context.ApplicationContext;
import org.springframework.core.Ordered;
import org.springframework.lang.Nullable;
import org.springframework.web.context.support.WebApplicationObjectSupport;
import org.springframework.web.servlet.View;
import org.springframework.web.servlet.ViewResolver;
/**
* A simple implementation of {@link org.springframework.web.servlet.ViewResolver}
* that interprets a view name as a bean name in the current application context,
* i.e. typically in the XML file of the executing {@code DispatcherServlet}
* or in a corresponding configuration class.
*
* Note: This {@code ViewResolver} implements the {@link Ordered} interface
* in order to allow for flexible participation in {@code ViewResolver} chaining.
* For example, some special views could be defined via this {@code ViewResolver}
* (giving it 0 as "order" value), while all remaining views could be resolved by
* a {@link UrlBasedViewResolver}.
*
* @author Juergen Hoeller
* @since 18.06.2003
* @see UrlBasedViewResolver
*/
public class BeanNameViewResolver extends WebApplicationObjectSupport implements ViewResolver, Ordered {
private int order = Ordered.LOWEST_PRECEDENCE; // default: same as non-Ordered
/**
* Specify the order value for this ViewResolver bean.
*
The default value is {@code Ordered.LOWEST_PRECEDENCE}, meaning non-ordered.
* @see org.springframework.core.Ordered#getOrder()
*/
public void setOrder(int order) {
this.order = order;
}
@Override
public int getOrder() {
return this.order;
}
@Override
@Nullable
public View resolveViewName(String viewName, Locale locale) throws BeansException {
ApplicationContext context = obtainApplicationContext();
if (!context.containsBean(viewName)) {
// Allow for ViewResolver chaining...
return null;
}
if (!context.isTypeMatch(viewName, View.class)) {
if (logger.isDebugEnabled()) {
logger.debug("Found bean named '" + viewName + "' but it does not implement View");
}
// Since we're looking into the general ApplicationContext here,
// let's accept this as a non-match and allow for chaining as well...
return null;
}
return context.getBean(viewName, View.class);
}
}