https://github.com/spring-projects/spring-framework: Spring Web (Spring IO)
  • Juergen Hoeller 
/*
 * Copyright 2002-2018 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.lang.Nullable;
import org.springframework.web.context.WebApplicationContext;


JSF NavigationHandler implementation that delegates to a NavigationHandler
bean obtained from the Spring root WebApplicationContext.

Configure this handler proxy in your faces-config.xml file as follows: 
<application>
  ...
  <navigation-handler>
	   org.springframework.web.jsf.DelegatingNavigationHandlerProxy
  </navigation-handler>
  ...
</application>

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.

<bean name="jsfNavigationHandler" class="mypackage.MyNavigationHandler">
  <property name="myProperty" ref="myOtherBean"/>
</bean>

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 not supported
in such a scenario, since we can't inject the original handler in standard
JSF style (that is, as constructor argument).

For decorating the original NavigationHandler, make sure that your
target bean extends Spring's DecoratingNavigationHandler 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!

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 FacesContextUtils.getWebApplicationContext(FacesContext)). 
Author:Juergen Hoeller, Colin Sampaleanu
See Also:
Since:1.2.7
/**
 * 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} file
 * as follows:
 *
 * <pre class="code">
 * &lt;application&gt;
 *   ...
 *   &lt;navigation-handler&gt;
 * 	   org.springframework.web.jsf.DelegatingNavigationHandlerProxy
 *   &lt;/navigation-handler&gt;
 *   ...
 * &lt;/application&gt;</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 class="code">
 * &lt;bean name="jsfNavigationHandler" class="mypackage.MyNavigationHandler"&gt;
 *   &lt;property name="myProperty" ref="myOtherBean"/&gt;
 * &lt;/bean&gt;</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".

/**
	 * Default name of the target bean in the Spring application context:
	 * "jsfNavigationHandler".
	 */
	public static final String DEFAULT_TARGET_BEAN_NAME = "jsfNavigationHandler";

	@Nullable
	private NavigationHandler originalNavigationHandler;


	
Create a new DelegatingNavigationHandlerProxy.

/**
	 * Create a new DelegatingNavigationHandlerProxy.
	 */
	public DelegatingNavigationHandlerProxy() {
	}

	
Create a new DelegatingNavigationHandlerProxy.

Params:
  • originalNavigationHandler – the original NavigationHandler
/**
	 * 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.

The target bean needs to extend the JSF NavigationHandler class. If it extends Spring's DecoratingNavigationHandler, the overloaded handleNavigation method with the original NavigationHandler as argument will be used. Else, the standard handleNavigation method will be called. 
/**
	 * 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} method with the original NavigationHandler
	 * as argument will be used. Else, the standard {@code handleNavigation}
	 * method will be called.
	 */
	@Override
	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.

By default, a bean with the name "jsfNavigationHandler" is obtained
from the Spring root WebApplicationContext, for every invocation.

Params:
  • facesContext – the current JSF context
See Also:
Returns:the target NavigationHandler to delegate to
/**
	 * 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 getBeanFactory(facesContext).getBean(targetBeanName, NavigationHandler.class);
	}

	
Return the name of the target NavigationHandler bean in the BeanFactory.
Default is "jsfNavigationHandler".

Params:
  • facesContext – the current JSF context
Returns:the name of the target bean
/**
	 * 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.

Default implementation delegates to getWebApplicationContext. Can be overridden to provide an arbitrary BeanFactory reference to resolve against; usually, this will be a full Spring ApplicationContext. 
Params:
  • facesContext – the current JSF context
See Also:
Returns:the Spring BeanFactory (never null)
/**
	 * Retrieve the Spring BeanFactory to delegate bean name resolution to.
	 * <p>Default implementation delegates to {@code getWebApplicationContext}.
	 * 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})
	 * @see #getWebApplicationContext
	 */
	protected BeanFactory getBeanFactory(FacesContext facesContext) {
		return getWebApplicationContext(facesContext);
	}

	
Retrieve the web application context to delegate bean name resolution to.

Default implementation delegates to FacesContextUtils.

Params:
  • facesContext – the current JSF context
See Also:
Returns:the Spring web application context (never null)
/**
	 * 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})
	 * @see FacesContextUtils#getRequiredWebApplicationContext
	 */
	protected WebApplicationContext getWebApplicationContext(FacesContext facesContext) {
		return FacesContextUtils.getRequiredWebApplicationContext(facesContext);
	}

}