code: public void constructDocument(String filePath, MappedKeyEngineer<K,V> engineer)
  	{
  		//clear cache		
  		try
  		{
  			crawl(new File(filePath), engineer);	
  		}
  		finally
  		{
  			crawledPaths.clear();
  		}		
  	}
docs: Director method to construct a document
  @param filePath the file path the output
  @param engineer the strategy