package org.apache.maven.wrapper;
   
   /*
    * 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.io.IOException;
  import java.io.InputStream;
  import java.nio.file.Files;
  import java.nio.file.Path;
  import java.util.HashMap;
  import java.util.Map;
  import java.util.Map.Entry;
  import java.util.Properties;
  import java.util.regex.Matcher;
  import java.util.regex.Pattern;
  
  /**
   * @author Hans Dockter
   */
  public class SystemPropertiesHandler
  {
  
      private static final Pattern SYSPROP_PATTERN = Pattern.compile( "systemProp\\.(.*)" );
  
      public static Map<String, String> getSystemProperties( Path propertiesFile )
      {
          Map<String, String> propertyMap = new HashMap<>();
          if ( !Files.isRegularFile( propertiesFile ) )
          {
              return propertyMap;
          }
          Properties properties = new Properties();
          try ( InputStream inStream = Files.newInputStream( propertiesFile ) )
          {
              properties.load( inStream );
          }
          catch ( IOException e )
          {
              throw new RuntimeException( "Error when loading properties file=" + propertiesFile, e );
          }
  
          for ( Entry<Object, Object> entrySet : properties.entrySet() )
          {
              Matcher matcher = SYSPROP_PATTERN.matcher( entrySet.getKey().toString() );
              if ( matcher.find() )
              {
                  String key = matcher.group( 1 );
                  if ( key.length() > 0 )
                  {
                      propertyMap.put( key, entrySet.getValue().toString() );
                  }
              }
          }
          return propertyMap;
      }
  }