/*
* 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.servlet.view;
import java.util.Locale;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.DisposableBean;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.beans.factory.NoSuchBeanDefinitionException;
import org.springframework.beans.factory.xml.ResourceEntityResolver;
import org.springframework.beans.factory.xml.XmlBeanDefinitionReader;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.core.Ordered;
import org.springframework.core.io.Resource;
import org.springframework.web.context.support.GenericWebApplicationContext;
import org.springframework.web.servlet.View;
/**
* Implementation of ViewResolver that uses bean definitions in an
* XML file, specified by resource location. The file will typically
* be located in the WEB-INF directory; default is "/WEB-INF/views.xml".
*
* <p>This ViewResolver does not support internationalization.
* Consider ResourceBundleViewResolver if you need to apply
* different view resources per locale.
*
* <p>Note: This ViewResolver implements the Ordered interface to allow for
* flexible participation in ViewResolver chaining. For example, some special
* views could be defined via this ViewResolver (giving it 0 as "order" value),
* while all remaining views could be resolved by a UrlBasedViewResolver.
*
* @author Juergen Hoeller
* @since 18.06.2003
* @see org.springframework.context.ApplicationContext#getResource
* @see ResourceBundleViewResolver
* @see UrlBasedViewResolver
*/
public class XmlViewResolver extends AbstractCachingViewResolver
implements Ordered, InitializingBean, DisposableBean {
/** Default if no other location is supplied */
public final static String DEFAULT_LOCATION = "/WEB-INF/views.xml";
private int order = Integer.MAX_VALUE; // default: same as non-Ordered
private Resource location;
private ConfigurableApplicationContext cachedFactory;
public void setOrder(int order) {
this.order = order;
}
public int getOrder() {
return order;
}
/**
* Set the location of the XML file that defines the view beans.
* <p>The default is "/WEB-INF/views.xml".
* @param location the location of the XML file.
*/
public void setLocation(Resource location) {
this.location = location;
}
/**
* Pre-initialize the factory from the XML file.
* Only effective if caching is enabled.
*/
public void afterPropertiesSet() throws BeansException {
if (isCache()) {
initFactory();
}
}
/**
* This implementation returns just the view name,
* as XmlViewResolver doesn't support localized resolution.
*/
@Override
protected Object getCacheKey(String viewName, Locale locale) {
return viewName;
}
@Override
protected View loadView(String viewName, Locale locale) throws BeansException {
BeanFactory factory = initFactory();
try {
return (View) factory.getBean(viewName, View.class);
}
catch (NoSuchBeanDefinitionException ex) {
// to allow for ViewResolver chaining
return null;
}
}
/**
* Initialize the view bean factory from the XML file.
* Synchronized because of access by parallel threads.
* @throws BeansException in case of initialization errors
*/
protected synchronized BeanFactory initFactory() throws BeansException {
if (this.cachedFactory != null) {
return this.cachedFactory;
}
Resource actualLocation = this.location;
if (actualLocation == null) {
actualLocation = getApplicationContext().getResource(DEFAULT_LOCATION);
}
// Create child ApplicationContext for views.
GenericWebApplicationContext factory = new GenericWebApplicationContext();
factory.setParent(getApplicationContext());
factory.setServletContext(getServletContext());
// Load XML resource with context-aware entity resolver.
XmlBeanDefinitionReader reader = new XmlBeanDefinitionReader(factory);
reader.setEnvironment(getApplicationContext().getEnvironment());
reader.setEntityResolver(new ResourceEntityResolver(getApplicationContext()));
reader.loadBeanDefinitions(actualLocation);
factory.refresh();
if (isCache()) {
this.cachedFactory = factory;
}
return factory;
}
/**
* Close the view bean factory on context shutdown.
*/
public void destroy() throws BeansException {
if (this.cachedFactory != null) {
this.cachedFactory.close();
}
}
}