package org.apache.maven.plugin.war;

 /*

  * Copyright 2001-2005 The Apache Software Foundation.

  *

  * Licensed 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.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 390314 2006-03-31 04:04:35Z brett $

  * @todo this is duplicated from the resources plugin - migrate to plexus-utils

  */

 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 loadPropertyFile( File propfile, boolean fail, boolean useSystemProps )

         throws IOException

     {

         Properties props = new Properties();

         if ( useSystemProps )

         {

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

         }

         if ( propfile.exists() )

         {

             FileInputStream inStream = new FileInputStream( propfile );

             try

             {

                 props.load( inStream );

             }

             finally

             {

                 IOUtil.close( inStream );

             }

         }

         else if ( fail )

         {

             throw new FileNotFoundException( propfile.toString() );

         }

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

         {

             String k = (String) n.nextElement();

             props.setProperty( k, PropertyUtils.getPropertyValue( k, props ) );

         }

         return props;

     }

     /**

      * Retrieves a property value, replacing values like ${token}

      * using the Properties to look them up.

      * <p/>

      * It will leave unresolved properties alone, trying for System

      * properties, and implements reparsing (in the case that

      * the value of a property contains a key), and will

      * not loop endlessly on a pair like

      * test = ${test}.

      */

     private static String getPropertyValue( String k, Properties p )

     {

         // This can also be done using InterpolationFilterReader,

         // but it requires reparsing the file over and over until

         // it doesn't change.

         String v = p.getProperty( k );

         String ret = "";

         int idx, idx2;

         while ( ( idx = v.indexOf( "${" ) ) >= 0 )

         {

             // append prefix to result

             ret += v.substring( 0, idx );

             // strip prefix from original

             v = v.substring( idx + 2 );

             // if no matching } then bail

             if ( ( idx2 = v.indexOf( '}' ) ) < 0 )

             {

                 break;

             }

             // strip out the key and resolve it

             // resolve the key/value for the ${statement}

             String nk = v.substring( 0, idx2 );

             v = v.substring( idx2 + 1 );

             String nv = p.getProperty( nk );

             // try global environment..

             if ( nv == null )

             {

                 nv = System.getProperty( nk );

             }

             // if the key cannot be resolved,

             // leave it alone ( and don't parse again )

             // else prefix the original string with the

             // resolved property ( so it can be parsed further )

             // taking recursion into account.

             if ( nv == null || nv.equals( k ) )

             {

                 ret += "${" + nk + "}";

             }

             else

             {

                 v = nv + v;

             }

         }

         return ret + v;

     }

 }