package org.apache.maven.shared.model.fileset.mappers;

 /*

  * 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.

  */

 import org.apache.maven.shared.model.fileset.Mapper;

 import org.codehaus.plexus.util.IOUtil;

 import java.io.IOException;

 import java.io.InputStream;

 import java.util.Properties;

 /**

  * Element to define a FileNameMapper.

  *

  * @version $Id: org.apache.maven.shared.model.fileset.mappers.MapperUtil.html 886882 2013-11-16 21:55:43Z hboutemy $

  */

 public final class MapperUtil

 {

     private static final String MAPPER_PROPERTIES = "mapper.properties";

     private static Properties implementations;

     private MapperUtil()

     {

         // nop

     }

     /**

      * Initializes a properties object to store the built-in classnames.

      */

     private static void initializeBuiltIns()

     {

         if ( implementations == null )

         {

             Properties props = new Properties();

             ClassLoader cloader = Thread.currentThread().getContextClassLoader();

             InputStream stream = null;

             try

             {

                 stream = cloader.getResourceAsStream( MAPPER_PROPERTIES );

                 if ( stream == null )

                 {

                     throw new IllegalStateException( "Cannot find classpath resource: " + MAPPER_PROPERTIES );

                 }

                 try

                 {

                     props.load( stream );

                 }

                 catch ( IOException e )

                 {

                     throw new IllegalStateException( "Cannot find classpath resource: " + MAPPER_PROPERTIES );

                 }

             }

             finally

             {

                 IOUtil.close( stream );

             }

         }

     }

     /**

      * Returns a fully configured FileNameMapper implementation.

      *

      * @param mapper

      * @return

      * @throws MapperException

      */

     public static FileNameMapper getFileNameMapper( Mapper mapper )

         throws MapperException

     {

         if ( mapper == null )

         {

             return null;

         }

         initializeBuiltIns();

         String type = mapper.getType();

         String classname = mapper.getClassname();

         if ( type == null && classname == null )

         {

             throw new MapperException( "nested mapper or " + "one of the attributes type or classname is required" );

         }

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

         {

             throw new MapperException( "must not specify both type and classname attribute" );

         }

         if ( type != null )

         {

             classname = implementations.getProperty( type );

         }

         try

         {

             FileNameMapper m = (FileNameMapper) Class.forName( classname ).newInstance();

             m.setFrom( mapper.getFrom() );

             m.setTo( mapper.getTo() );

             return m;

         }

         catch ( ClassNotFoundException e )

         {

             throw new MapperException( "Cannot find mapper implementation: " + classname, e );

         }

         catch ( InstantiationException e )

         {

             throw new MapperException( "Cannot load mapper implementation: " + classname, e );

         }

         catch ( IllegalAccessException e )

         {

             throw new MapperException( "Cannot load mapper implementation: " + classname, e );

         }

     }

 }