/*
* Copyright 2002-2006 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.jsf;
import javax.faces.application.NavigationHandler;
import javax.faces.context.FacesContext;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.web.context.WebApplicationContext;
/**
* JSF NavigationHandler implementation that delegates to a NavigationHandler
* bean obtained from the Spring root WebApplicationContext.
*
* <p>Configure this handler proxy in your <code>faces-config.xml</code> file
* as follows:
*
* <pre>
* <application>
* ...
* <navigation-handler>
* org.springframework.web.jsf.DelegatingNavigationHandlerProxy
* </navigation-handler>
* ...
* </application></pre>
*
* By default, the Spring ApplicationContext will be searched for the NavigationHandler
* under the bean name "jsfNavigationHandler". In the simplest case, this is a plain
* Spring bean definition like the following. However, all of Spring's bean configuration
* power can be applied to such a bean, in particular all flavors of dependency injection.
*
* <pre>
* <bean name="jsfNavigationHandler" class="mypackage.MyNavigationHandler">
* <property name="myProperty" ref="myOtherBean"/>
* </bean></pre>
*
* The target NavigationHandler bean will typically extend the standard JSF
* NavigationHandler class. However, note that decorating the original
* NavigationHandler (the JSF provider's default handler) is <i>not</i> supported
* in such a scenario, since we can't inject the original handler in standard
* JSF style (that is, as constructor argument).
*
* <p>For <b>decorating the original NavigationHandler</b>, make sure that your
* target bean extends Spring's <b>DecoratingNavigationHandler</b> class. This
* allows to pass in the original handler as method argument, which this proxy
* automatically detects. Note that a DecoratingNavigationHandler subclass
* will still work as standard JSF NavigationHandler as well!
*
* <p>This proxy may be subclassed to change the bean name used to search for the
* navigation handler, change the strategy used to obtain the target handler,
* or change the strategy used to access the ApplicationContext (normally obtained
* via {@link FacesContextUtils#getWebApplicationContext(FacesContext)}).
*
* @author Juergen Hoeller
* @author Colin Sampaleanu
* @since 1.2.7
* @see DecoratingNavigationHandler
*/
public class DelegatingNavigationHandlerProxy extends NavigationHandler {
/**
* Default name of the target bean in the Spring application context:
* "jsfNavigationHandler"
*/
public final static String DEFAULT_TARGET_BEAN_NAME = "jsfNavigationHandler";
private NavigationHandler originalNavigationHandler;
/**
* Create a new DelegatingNavigationHandlerProxy.
*/
public DelegatingNavigationHandlerProxy() {
}
/**
* Create a new DelegatingNavigationHandlerProxy.
* @param originalNavigationHandler the original NavigationHandler
*/
public DelegatingNavigationHandlerProxy(NavigationHandler originalNavigationHandler) {
this.originalNavigationHandler = originalNavigationHandler;
}
/**
* Handle the navigation request implied by the specified parameters,
* through delegating to the target bean in the Spring application context.
* <p>The target bean needs to extend the JSF NavigationHandler class.
* If it extends Spring's DecoratingNavigationHandler, the overloaded
* <code>handleNavigation</code> method with the original NavigationHandler
* as argument will be used. Else, the standard <code>handleNavigation</code>
* method will be called.
*/
public void handleNavigation(FacesContext facesContext, String fromAction, String outcome) {
NavigationHandler handler = getDelegate(facesContext);
if (handler instanceof DecoratingNavigationHandler) {
((DecoratingNavigationHandler) handler).handleNavigation(
facesContext, fromAction, outcome, this.originalNavigationHandler);
}
else {
handler.handleNavigation(facesContext, fromAction, outcome);
}
}
/**
* Return the target NavigationHandler to delegate to.
* <p>By default, a bean with the name "jsfNavigationHandler" is obtained
* from the Spring root WebApplicationContext, for every invocation.
* @param facesContext the current JSF context
* @return the target NavigationHandler to delegate to
* @see #getTargetBeanName
* @see #getBeanFactory
*/
protected NavigationHandler getDelegate(FacesContext facesContext) {
String targetBeanName = getTargetBeanName(facesContext);
return (NavigationHandler) getBeanFactory(facesContext).getBean(targetBeanName, NavigationHandler.class);
}
/**
* Return the name of the target NavigationHandler bean in the BeanFactory.
* Default is "jsfNavigationHandler".
* @param facesContext the current JSF context
* @return the name of the target bean
*/
protected String getTargetBeanName(FacesContext facesContext) {
return DEFAULT_TARGET_BEAN_NAME;
}
/**
* Retrieve the Spring BeanFactory to delegate bean name resolution to.
* <p>Default implementation delegates to <code>getWebApplicationContext</code>.
* Can be overridden to provide an arbitrary BeanFactory reference to resolve
* against; usually, this will be a full Spring ApplicationContext.
* @param facesContext the current JSF context
* @return the Spring BeanFactory (never <code>null</code>)
* @see #getWebApplicationContext
*/
protected BeanFactory getBeanFactory(FacesContext facesContext) {
return getWebApplicationContext(facesContext);
}
/**
* Retrieve the web application context to delegate bean name resolution to.
* <p>Default implementation delegates to FacesContextUtils.
* @param facesContext the current JSF context
* @return the Spring web application context (never <code>null</code>)
* @see FacesContextUtils#getRequiredWebApplicationContext
*/
protected WebApplicationContext getWebApplicationContext(FacesContext facesContext) {
return FacesContextUtils.getRequiredWebApplicationContext(facesContext);
}
}