package ca.uhn.hl7v2.util;
   
   import java.io.File;
   
   import org.slf4j.Logger;
   import org.slf4j.LoggerFactory;
   
   /**
    * Used to access the hapi.home system property.  Note that the property 
   * is only checked (at most) once per session.  
   * @author Bryan Tripp
   */
  public class Home {
      
      private static File home;
      private static final Logger log = LoggerFactory.getLogger(Home.class);
      
      /** Creates a new instance of Home */
      public Home() {
      }
      
      /**
       * Returns a File object corresponding to the directory specified in 
       * the system property hapi.home.  The property is only checked the 
       * first time this method is called, so changes will not take place 
       * until a new VM is started.  
       * This method is guaranteed to return a directory.  If hapi.home is 
       * not set, or is set to a non-directory path, the current working directory will 
       * be used.  
       */
      public static File getHomeDirectory() {
          if (home == null) 
              setHomeDirectory();
          
          return home;
      }
      
      private synchronized static void setHomeDirectory() {
          String dir = System.getProperty("hapi.home", ".");
          home = new File(dir);
          
          if (!home.isDirectory()) {
              home = new File("."); 
              log.warn("The system property hapi.home is not a valid directory: {}.  Using . instead", dir);
          }
           
          log.info("hapi.home is set to " + home.getAbsolutePath());
      }
      
      public static void main(String[] args) {
          System.out.println("HOME: " + getHomeDirectory().getAbsolutePath());
      }
          
  }