/*

  * Licensed to the Apache Software Foundation (ASF) under one

  * or more contributor license agreements.  See the NOTICE file

  * distributed with this work for additional information

  * regarding copyright ownership.  The ASF licenses this file

  * to you 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.apache.myfaces.view.facelets.tag.jsf.core;

 import java.io.IOException;

 import java.io.Serializable;

 import javax.el.ELException;

 import javax.el.ValueExpression;

 import javax.faces.FacesException;

 import javax.faces.component.UIComponent;

 import javax.faces.component.UIViewRoot;

 import javax.faces.context.FacesContext;

 import javax.faces.event.AbortProcessingException;

 import javax.faces.event.PhaseEvent;

 import javax.faces.event.PhaseId;

 import javax.faces.event.PhaseListener;

 import javax.faces.view.facelets.ComponentHandler;

 import javax.faces.view.facelets.FaceletContext;

 import javax.faces.view.facelets.FaceletException;

 import javax.faces.view.facelets.TagAttribute;

 import javax.faces.view.facelets.TagAttributeException;

 import javax.faces.view.facelets.TagConfig;

 import javax.faces.view.facelets.TagException;

 import javax.faces.view.facelets.TagHandler;

 import org.apache.myfaces.buildtools.maven2.plugin.builder.annotation.JSFFaceletTag;

 import org.apache.myfaces.view.facelets.tag.jsf.ComponentSupport;

 import org.apache.myfaces.view.facelets.util.ReflectionUtil;

 @JSFFaceletTag(

         name = "f:phaseListener",

         bodyContent = "empty", 

         tagClass="org.apache.myfaces.taglib.core.PhaseListenerTag")

 public class PhaseListenerHandler extends TagHandler

 {

     private final static class LazyPhaseListener implements PhaseListener, Serializable

     {

         private static final long serialVersionUID = -6496143057319213401L;

         private final String type;

         private final ValueExpression binding;

         public LazyPhaseListener(String type, ValueExpression binding)

         {

             this.type = type;

             this.binding = binding;

         }

         private PhaseListener getInstance()

         {

             PhaseListener instance = null;

             FacesContext faces = FacesContext.getCurrentInstance();

             if (faces == null)

             {

                 return null;

             }

             if (this.binding != null)

             {

                 instance = (PhaseListener) binding.getValue(faces.getELContext());

             }

             if (instance == null && type != null)

             {

                 try

                 {

                     instance = (PhaseListener) ReflectionUtil.forName(this.type).newInstance();

                 }

                 catch (Exception e)

                 {

                     throw new AbortProcessingException("Couldn't Lazily instantiate PhaseListener", e);

                 }

                 if (this.binding != null)

                 {

                     binding.setValue(faces.getELContext(), instance);

                 }

             }

             return instance;

         }

         public void afterPhase(PhaseEvent event)

         {

             PhaseListener pl = this.getInstance();

             if (pl != null)

             {

                 pl.afterPhase(event);

             }

         }

         public void beforePhase(PhaseEvent event)

         {

             PhaseListener pl = this.getInstance();

             if (pl != null)

             {

                 pl.beforePhase(event);

             }

         }

         public PhaseId getPhaseId()

         {

             PhaseListener pl = this.getInstance();

             return (pl != null) ? pl.getPhaseId() : PhaseId.ANY_PHASE;

         }

     }

     private final TagAttribute binding;

     private final String listenerType;

     public PhaseListenerHandler(TagConfig config)

     {

         super(config);

         TagAttribute type = this.getAttribute("type");

         this.binding = this.getAttribute("binding");

         if (type != null)

         {

             if (!type.isLiteral())

             {

                 throw new TagAttributeException(type, "Must be a literal class name of type PhaseListener");

             }

             else

             {

                 // test it out

                 try

                 {

                     ReflectionUtil.forName(type.getValue());

                 }

                 catch (ClassNotFoundException e)

                 {

                     throw new TagAttributeException(type, "Couldn't qualify PhaseListener", e);

                 }

             }

             this.listenerType = type.getValue();

         }

         else

         {

             this.listenerType = null;

         }

     }

     public void apply(FaceletContext ctx, UIComponent parent) throws IOException, FacesException, FaceletException,

             ELException

     {

         if (ComponentHandler.isNew(parent))

         {

             UIViewRoot root = ComponentSupport.getViewRoot(ctx, parent);

             if (root == null)

             {

                 throw new TagException(this.tag, "UIViewRoot not available");

             }

             ValueExpression b = null;

             if (this.binding != null)

             {

                 b = this.binding.getValueExpression(ctx, PhaseListener.class);

             }

             PhaseListener pl = new LazyPhaseListener(this.listenerType, b);

             root.addPhaseListener(pl);

         }

     }

 }