/*
 * Copyright 2002-2012 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.jsf;

import java.util.Collection;

import javax.faces.context.FacesContext;
import javax.faces.event.PhaseEvent;
import javax.faces.event.PhaseId;
import javax.faces.event.PhaseListener;

import org.springframework.beans.factory.BeanFactoryUtils;
import org.springframework.beans.factory.ListableBeanFactory;
import org.springframework.web.context.WebApplicationContext;

JSF PhaseListener implementation that delegates to one or more Spring-managed
PhaseListener beans coming from the Spring root WebApplicationContext.
Configure this listener multicaster in your faces-config.xml file as follows: 
<application>
  ...
  <phase-listener>
    org.springframework.web.jsf.DelegatingPhaseListenerMulticaster
  </phase-listener>
  ...
</application>
 The multicaster will delegate all beforePhase and afterPhase events to all target PhaseListener beans. By default, those will simply be obtained by type: All beans in the Spring root WebApplicationContext that implement the PhaseListener interface will be fetched and invoked. 
Note: This multicaster's getPhaseId() method will always return ANY_PHASE. The phase id exposed by the target listener beans
will be ignored; all events will be propagated to all listeners.
This multicaster may be subclassed to change the strategy used to obtain the listener beans, or to change the strategy used to access the ApplicationContext (normally obtained via FacesContextUtils.getWebApplicationContext(FacesContext)). 
Author:
Juergen Hoeller, Colin Sampaleanu
Since:
1.2.7/**
 * JSF PhaseListener implementation that delegates to one or more Spring-managed
 * PhaseListener beans coming from the Spring root WebApplicationContext.
 *
 * <p>Configure this listener multicaster in your {@code faces-config.xml} file
 * as follows:
 *
 * <pre class="code">
 * &lt;application&gt;
 *   ...
 *   &lt;phase-listener&gt;
 *     org.springframework.web.jsf.DelegatingPhaseListenerMulticaster
 *   &lt;/phase-listener&gt;
 *   ...
 * &lt;/application&gt;</pre>
 *
 * The multicaster will delegate all {@code beforePhase} and {@code afterPhase}
 * events to all target PhaseListener beans. By default, those will simply be obtained
 * by type: All beans in the Spring root WebApplicationContext that implement the
 * PhaseListener interface will be fetched and invoked.
 *
 * <p>Note: This multicaster's {@code getPhaseId()} method will always return
 * {@code ANY_PHASE}. <b>The phase id exposed by the target listener beans
 * will be ignored; all events will be propagated to all listeners.</b>
 *
 * <p>This multicaster may be subclassed to change the strategy used to obtain
 * the listener beans, or to 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
 */
@SuppressWarnings("serial")
public class DelegatingPhaseListenerMulticaster implements PhaseListener {

	@Override
	public PhaseId getPhaseId() {
		return PhaseId.ANY_PHASE;
	}

	@Override
	public void beforePhase(PhaseEvent event) {
		for (PhaseListener listener : getDelegates(event.getFacesContext())) {
			listener.beforePhase(event);
		}
	}

	@Override
	public void afterPhase(PhaseEvent event) {
		for (PhaseListener listener : getDelegates(event.getFacesContext())) {
			listener.afterPhase(event);
		}
	}


	
Obtain the delegate PhaseListener beans from the Spring root WebApplicationContext.
Params:
facesContext – the current JSF context
See Also:
getBeanFactory
ListableBeanFactory.getBeansOfType(Class<Object>)
Returns:
a Collection of PhaseListener objects/**
	 * Obtain the delegate PhaseListener beans from the Spring root WebApplicationContext.
	 * @param facesContext the current JSF context
	 * @return a Collection of PhaseListener objects
	 * @see #getBeanFactory
	 * @see org.springframework.beans.factory.ListableBeanFactory#getBeansOfType(Class)
	 */
	protected Collection<PhaseListener> getDelegates(FacesContext facesContext) {
		ListableBeanFactory bf = getBeanFactory(facesContext);
		return BeanFactoryUtils.beansOfTypeIncludingAncestors(bf, PhaseListener.class, true, false).values();
	}

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

	
Retrieve the web application context to delegate bean name resolution to.
The default implementation delegates to FacesContextUtils.
Params:
facesContext – the current JSF context
See Also:
FacesContextUtils.getRequiredWebApplicationContext
Returns:
the Spring web application context (never null)/**
	 * Retrieve the web application context to delegate bean name resolution to.
	 * <p>The 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);
	}

}