/*

  * 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;

 import javax.el.ELException;

 import javax.faces.FacesException;

 import javax.faces.view.facelets.FaceletException;

 import java.io.IOException;

 import java.net.URL;

 import java.util.Map;

 import javax.faces.context.FacesContext;

 import javax.faces.view.facelets.Facelet;

 import javax.faces.view.facelets.FaceletContext;

 /**

  * FaceletFactory for producing Facelets relative to the context of the underlying implementation.

  * 

  * @author Jacob Hookom

  * @version $Id$

  */

 public abstract class FaceletFactory

 {

     private static ThreadLocal<FaceletFactory> instance = new ThreadLocal<FaceletFactory>();

     public final static String LAST_RESOURCE_RESOLVED = "oam.facelets.LAST_RESOURCE_RESOLVED";

     /**

      * Return a Facelet instance as specified by the file at the passed URI.

      * 

      * @param uri

      * @return

      * @throws IOException

      * @throws FaceletException

      * @throws FacesException

      * @throws ELException

      */

     public abstract Facelet getFacelet(FacesContext context, String uri) throws IOException;

     /**

      * Create a Facelet from the passed URL. This method checks if the cached Facelet needs to be refreshed before

      * returning. If so, uses the passed URL to build a new instance;

      * 

      * @param url

      *            source url

      * @return Facelet instance

      * @throws IOException

      * @throws FaceletException

      * @throws FacesException

      * @throws ELException

      */

     public abstract Facelet getFacelet(URL url) throws IOException, FaceletException, FacesException, ELException;

     /**

      * Create a Facelet from the passed URL, but take into account the context. This method is

      * useful in cases where the facelet instance must replace the one in the cache based on 

      * the context, instead take the one from the cache, like for example when the EL expression

      * cache is used.

      * 

      * @param url

      *            source url

      * @return Facelet instance

      * @throws IOException

      * @throws FaceletException

      * @throws FacesException

      * @throws ELException

      */

     public abstract Facelet getFacelet(FaceletContext ctx, URL url)

         throws IOException, FaceletException, FacesException, ELException;    

     /**

      * Return a Facelet instance as specified by the file at the passed URI. The returned facelet is used

      * to create view metadata in this form: 

      * <p>

      * UIViewRoot(in facet javax_faces_metadata(one or many UIViewParameter instances))

      * </p>

      * <p>

      * This method should be called from FaceletViewMetadata.createMetadataView(FacesContext context)  

      * </p>

      * 

      * @since 2.0

      * @param uri

      * @return

      * @throws IOException

      */

     public abstract Facelet getViewMetadataFacelet(

         FacesContext context, String uri) throws IOException;

     /**

      * Create a Facelet used to create view metadata from the passed URL. This method checks if the 

      * cached Facelet needs to be refreshed before returning. If so, uses the passed URL to build a new instance;

      * 

      * @since 2.0

      * @param url source url

      * @return Facelet instance

      * @throws IOException

      * @throws FaceletException

      * @throws FacesException

      * @throws ELException

      */

     public abstract Facelet getViewMetadataFacelet(URL url)

             throws IOException, FaceletException, FacesException, ELException;

     /**

      * Return a Facelet instance as specified by the file at the passed URI. The returned facelet is used

      * to create composite component metadata.

      * <p>

      * This method should be called from vdl.getComponentMetadata(FacesContext context)  

      * </p>

      * 

      * @since 2.0.1

      * @param uri

      * @return

      * @throws IOException

      */

     public abstract Facelet getCompositeComponentMetadataFacelet(FacesContext context, String uri) 

         throws IOException;

     /**

      * Create a Facelet used to create composite component metadata from the passed URL. This method checks if the 

      * cached Facelet needs to be refreshed before returning. If so, uses the passed URL to build a new instance.

      * 

      * @since 2.0.1

      * @param url source url

      * @return Facelet instance

      * @throws IOException

      * @throws FaceletException

      * @throws FacesException

      * @throws ELException

      */

     public abstract Facelet getCompositeComponentMetadataFacelet(URL url)

             throws IOException, FaceletException, FacesException, ELException;

     /**

      * Compile a component tag on the fly.

      * 

      * @param taglibURI

      * @param tagName

      * @param attributes

      * @return 

      */

     public abstract Facelet compileComponentFacelet(String taglibURI, String tagName, Map<String,Object> attributes);

     /**

      * Set the static instance

      * 

      * @param factory

      */

     public static final void setInstance(FaceletFactory factory)

     {

         if (factory == null)

         {

             instance.remove();

         }

         else

         {

             instance.set(factory);

         }

     }

     /**

      * Get the static instance

      * 

      * @return

      */

     public static final FaceletFactory getInstance()

     {

         return instance.get();

     }

 }