package org.apache.maven.plugin.assembly.utils;

 /*

  * 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 java.util.Properties;

 /**

  * @version $Id: PrefixedPropertiesInterpolationValueSource.java 629920 2008-02-21 18:46:13Z jdcasey $

  */

 public class PrefixedPropertiesInterpolationValueSource

     extends PropertiesInterpolationValueSource

 {

     private final String prefix;

     public PrefixedPropertiesInterpolationValueSource( String prefix, Properties properties )

     {

         super( properties );

         this.prefix = prefix;

     }

     public Object getValue( String expression )

     {

         if ( ( expression == null ) || !expression.startsWith( prefix ) )

         {

             return null;

         }

         String realExpr = expression.substring( prefix.length() );

         if ( realExpr.startsWith( "." ) )

         {

             realExpr = realExpr.substring( 1 );

         }

         return super.getValue( realExpr );

     }

 }