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 org.apache.maven.plugin.assembly.format.AssemblyFormattingException;

 import org.codehaus.plexus.interpolation.InterpolationException;

 import org.codehaus.plexus.interpolation.PropertiesBasedValueSource;

 import org.codehaus.plexus.interpolation.StringSearchInterpolator;

 import org.codehaus.plexus.util.IOUtil;

 import java.io.File;

 import java.io.FileInputStream;

 import java.io.FileNotFoundException;

 import java.io.IOException;

 import java.util.Enumeration;

 import java.util.Properties;

 /**

  * @author <a href="mailto:kenney@neonics.com">Kenney Westerhof</a>

  * @version $Id: PropertyUtils.java 999612 2010-09-21 20:34:50Z jdcasey $

  */

 public final class PropertyUtils

 {

     private PropertyUtils()

     {

         // prevent instantiation

     }

     /**

      * Reads a property file, resolving all internal variables.

      * 

      * @param propfile

      *            The property file to load

      * @param fail

      *            wheter to throw an exception when the file cannot be loaded or to return null

      * @param useSystemProps

      *            wheter to incorporate System.getProperties settings into the returned Properties object.

      * @return the loaded and fully resolved Properties object

      */

     public static Properties getInterpolatedPropertiesFromFile( final File propfile, final boolean fail,

                                                                 final boolean useSystemProps )

         throws IOException, AssemblyFormattingException

     {

         Properties props;

         if ( useSystemProps )

         {

             props = new Properties( System.getProperties() );

         }

         else

         {

             props = new Properties();

         }

         if ( propfile.exists() )

         {

             final FileInputStream inStream = new FileInputStream( propfile );

             try

             {

                 props.load( inStream );

             }

             finally

             {

                 IOUtil.close( inStream );

             }

         }

         else if ( fail )

         {

             throw new FileNotFoundException( propfile.toString() );

         }

         final StringSearchInterpolator interpolator = new StringSearchInterpolator();

         interpolator.addValueSource( new PropertiesBasedValueSource( props ) );

         for ( @SuppressWarnings( "rawtypes" )

         final Enumeration n = props.propertyNames(); n.hasMoreElements(); )

         {

             final String key = (String) n.nextElement();

             String value = props.getProperty( key );

             try

             {

                 value = interpolator.interpolate( value );

             }

             catch ( final InterpolationException e )

             {

                 throw new AssemblyFormattingException( "Failed to interpolate property value: '" + value

                                 + "' for key: '" + key + "'. Reason: " + e.getMessage(), e );

             }

             props.setProperty( key, value );

         }

         return props;

     }

 }