/*
* Copyright 2002-2016 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.config.annotation;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;
import org.springframework.beans.factory.BeanFactoryUtils;
import org.springframework.beans.factory.BeanInitializationException;
import org.springframework.context.ApplicationContext;
import org.springframework.core.Ordered;
import org.springframework.util.CollectionUtils;
import org.springframework.util.ObjectUtils;
import org.springframework.web.accept.ContentNegotiationManager;
import org.springframework.web.servlet.View;
import org.springframework.web.servlet.ViewResolver;
import org.springframework.web.servlet.view.BeanNameViewResolver;
import org.springframework.web.servlet.view.ContentNegotiatingViewResolver;
import org.springframework.web.servlet.view.InternalResourceViewResolver;
import org.springframework.web.servlet.view.freemarker.FreeMarkerConfigurer;
import org.springframework.web.servlet.view.freemarker.FreeMarkerViewResolver;
import org.springframework.web.servlet.view.groovy.GroovyMarkupConfigurer;
import org.springframework.web.servlet.view.groovy.GroovyMarkupViewResolver;
import org.springframework.web.servlet.view.script.ScriptTemplateConfigurer;
import org.springframework.web.servlet.view.script.ScriptTemplateViewResolver;
import org.springframework.web.servlet.view.tiles3.TilesConfigurer;
import org.springframework.web.servlet.view.tiles3.TilesViewResolver;
/**
* Assist with the configuration of a chain of
* {@link org.springframework.web.servlet.ViewResolver ViewResolver} instances.
* This class is expected to be used via {@link WebMvcConfigurer#configureViewResolvers}.
*
* @author Sebastien Deleuze
* @author Rossen Stoyanchev
* @since 4.1
*/
public class ViewResolverRegistry {
private ContentNegotiatingViewResolver contentNegotiatingResolver;
private final List<ViewResolver> viewResolvers = new ArrayList<>(4);
private Integer order;
private ContentNegotiationManager contentNegotiationManager;
private ApplicationContext applicationContext;
protected void setContentNegotiationManager(ContentNegotiationManager contentNegotiationManager) {
this.contentNegotiationManager = contentNegotiationManager;
}
protected void setApplicationContext(ApplicationContext applicationContext) {
this.applicationContext = applicationContext;
}
/**
* Whether any view resolvers have been registered.
*/
public boolean hasRegistrations() {
return (this.contentNegotiatingResolver != null || !this.viewResolvers.isEmpty());
}
/**
* Enable use of a {@link ContentNegotiatingViewResolver} to front all other
* configured view resolvers and select among all selected Views based on
* media types requested by the client (e.g. in the Accept header).
* <p>If invoked multiple times the provided default views will be added to
* any other default views that may have been configured already.
* @see ContentNegotiatingViewResolver#setDefaultViews
*/
public void enableContentNegotiation(View... defaultViews) {
initContentNegotiatingViewResolver(defaultViews);
}
/**
* Enable use of a {@link ContentNegotiatingViewResolver} to front all other
* configured view resolvers and select among all selected Views based on
* media types requested by the client (e.g. in the Accept header).
* <p>If invoked multiple times the provided default views will be added to
* any other default views that may have been configured already.
*
* @see ContentNegotiatingViewResolver#setDefaultViews
*/
public void enableContentNegotiation(boolean useNotAcceptableStatus, View... defaultViews) {
initContentNegotiatingViewResolver(defaultViews);
this.contentNegotiatingResolver.setUseNotAcceptableStatusCode(useNotAcceptableStatus);
}
private void initContentNegotiatingViewResolver(View[] defaultViews) {
// ContentNegotiatingResolver in the registry: elevate its precedence!
this.order = (this.order != null ? this.order : Ordered.HIGHEST_PRECEDENCE);
if (this.contentNegotiatingResolver != null) {
if (!ObjectUtils.isEmpty(defaultViews)) {
if (!CollectionUtils.isEmpty(this.contentNegotiatingResolver.getDefaultViews())) {
List<View> views = new ArrayList<>(this.contentNegotiatingResolver.getDefaultViews());
views.addAll(Arrays.asList(defaultViews));
this.contentNegotiatingResolver.setDefaultViews(views);
}
}
}
else {
this.contentNegotiatingResolver = new ContentNegotiatingViewResolver();
this.contentNegotiatingResolver.setDefaultViews(Arrays.asList(defaultViews));
this.contentNegotiatingResolver.setViewResolvers(this.viewResolvers);
this.contentNegotiatingResolver.setContentNegotiationManager(this.contentNegotiationManager);
}
}
/**
* Register JSP view resolver using a default view name prefix of "/WEB-INF/"
* and a default suffix of ".jsp".
* <p>When this method is invoked more than once, each call will register a
* new ViewResolver instance. Note that since it's not easy to determine
* if a JSP exists without forwarding to it, using multiple JSP-based view
* resolvers only makes sense in combination with the "viewNames" property
* on the resolver indicating which view names are handled by which resolver.
*/
public UrlBasedViewResolverRegistration jsp() {
return jsp("/WEB-INF/", ".jsp");
}
/**
* Register JSP view resolver with the specified prefix and suffix.
* <p>When this method is invoked more than once, each call will register a
* new ViewResolver instance. Note that since it's not easy to determine
* if a JSP exists without forwarding to it, using multiple JSP-based view
* resolvers only makes sense in combination with the "viewNames" property
* on the resolver indicating which view names are handled by which resolver.
*/
public UrlBasedViewResolverRegistration jsp(String prefix, String suffix) {
InternalResourceViewResolver resolver = new InternalResourceViewResolver();
resolver.setPrefix(prefix);
resolver.setSuffix(suffix);
this.viewResolvers.add(resolver);
return new UrlBasedViewResolverRegistration(resolver);
}
/**
* Register Tiles 3.x view resolver.
* <p><strong>Note</strong> that you must also configure Tiles by adding a
* {@link org.springframework.web.servlet.view.tiles3.TilesConfigurer} bean.
*/
public UrlBasedViewResolverRegistration tiles() {
if (this.applicationContext != null && !hasBeanOfType(TilesConfigurer.class)) {
throw new BeanInitializationException("In addition to a Tiles view resolver " +
"there must also be a single TilesConfigurer bean in this web application context " +
"(or its parent).");
}
TilesRegistration registration = new TilesRegistration();
this.viewResolvers.add(registration.getViewResolver());
return registration;
}
/**
* Register a FreeMarker view resolver with an empty default view name
* prefix and a default suffix of ".ftl".
* <p><strong>Note</strong> that you must also configure FreeMarker by adding a
* {@link org.springframework.web.servlet.view.freemarker.FreeMarkerConfigurer} bean.
*/
public UrlBasedViewResolverRegistration freeMarker() {
if (this.applicationContext != null && !hasBeanOfType(FreeMarkerConfigurer.class)) {
throw new BeanInitializationException("In addition to a FreeMarker view resolver " +
"there must also be a single FreeMarkerConfig bean in this web application context " +
"(or its parent): FreeMarkerConfigurer is the usual implementation. " +
"This bean may be given any name.");
}
FreeMarkerRegistration registration = new FreeMarkerRegistration();
this.viewResolvers.add(registration.getViewResolver());
return registration;
}
/**
* Register a Groovy markup view resolver with an empty default view name
* prefix and a default suffix of ".tpl".
*/
public UrlBasedViewResolverRegistration groovy() {
if (this.applicationContext != null && !hasBeanOfType(GroovyMarkupConfigurer.class)) {
throw new BeanInitializationException("In addition to a Groovy markup view resolver " +
"there must also be a single GroovyMarkupConfig bean in this web application context " +
"(or its parent): GroovyMarkupConfigurer is the usual implementation. " +
"This bean may be given any name.");
}
GroovyMarkupRegistration registration = new GroovyMarkupRegistration();
this.viewResolvers.add(registration.getViewResolver());
return registration;
}
/**
* Register a script template view resolver with an empty default view name prefix and suffix.
* @since 4.2
*/
public UrlBasedViewResolverRegistration scriptTemplate() {
if (this.applicationContext != null && !hasBeanOfType(ScriptTemplateConfigurer.class)) {
throw new BeanInitializationException("In addition to a script template view resolver " +
"there must also be a single ScriptTemplateConfig bean in this web application context " +
"(or its parent): ScriptTemplateConfigurer is the usual implementation. " +
"This bean may be given any name.");
}
ScriptRegistration registration = new ScriptRegistration();
this.viewResolvers.add(registration.getViewResolver());
return registration;
}
/**
* Register a bean name view resolver that interprets view names as the names
* of {@link org.springframework.web.servlet.View} beans.
*/
public void beanName() {
BeanNameViewResolver resolver = new BeanNameViewResolver();
this.viewResolvers.add(resolver);
}
/**
* Register a {@link ViewResolver} bean instance. This may be useful to
* configure a custom (or 3rd party) resolver implementation. It may also be
* used as an alternative to other registration methods in this class when
* they don't expose some more advanced property that needs to be set.
*/
public void viewResolver(ViewResolver viewResolver) {
if (viewResolver instanceof ContentNegotiatingViewResolver) {
throw new BeanInitializationException(
"addViewResolver cannot be used to configure a ContentNegotiatingViewResolver. " +
"Please use the method enableContentNegotiation instead.");
}
this.viewResolvers.add(viewResolver);
}
/**
* ViewResolver's registered through this registry are encapsulated in an
* instance of {@link org.springframework.web.servlet.view.ViewResolverComposite
* ViewResolverComposite} and follow the order of registration.
* This property determines the order of the ViewResolverComposite itself
* relative to any additional ViewResolver's (not registered here) present in
* the Spring configuration
* <p>By default this property is not set, which means the resolver is ordered
* at {@link Ordered#LOWEST_PRECEDENCE} unless content negotiation is enabled
* in which case the order (if not set explicitly) is changed to
* {@link Ordered#HIGHEST_PRECEDENCE}.
*/
public void order(int order) {
this.order = order;
}
protected boolean hasBeanOfType(Class<?> beanType) {
return !ObjectUtils.isEmpty(BeanFactoryUtils.beanNamesForTypeIncludingAncestors(
this.applicationContext, beanType, false, false));
}
protected int getOrder() {
return (this.order != null ? this.order : Ordered.LOWEST_PRECEDENCE);
}
protected List<ViewResolver> getViewResolvers() {
if (this.contentNegotiatingResolver != null) {
return Collections.<ViewResolver>singletonList(this.contentNegotiatingResolver);
}
else {
return this.viewResolvers;
}
}
private static class TilesRegistration extends UrlBasedViewResolverRegistration {
public TilesRegistration() {
super(new TilesViewResolver());
}
}
private static class FreeMarkerRegistration extends UrlBasedViewResolverRegistration {
public FreeMarkerRegistration() {
super(new FreeMarkerViewResolver());
getViewResolver().setSuffix(".ftl");
}
}
private static class GroovyMarkupRegistration extends UrlBasedViewResolverRegistration {
public GroovyMarkupRegistration() {
super(new GroovyMarkupViewResolver());
getViewResolver().setSuffix(".tpl");
}
}
private static class ScriptRegistration extends UrlBasedViewResolverRegistration {
public ScriptRegistration() {
super(new ScriptTemplateViewResolver());
getViewResolver();
}
}
}