code: @Override
    public Integer getId() {
      try {
        return ProcessUtils.readPid(ProcessUtils.findPidFile(getDirectory()));
      }
      catch (Throwable cause) {
        if (cause instanceof PidUnknownException) {
          throw (PidUnknownException) cause;
        }
  
        throw new PidUnknownException("Process ID (PID) cannot be determined", cause);
      }
    }
docs: Returns the identifier of the {@link Process} (PID).
  
  @return an integer value containing the {@link Process} ID (PID).
  @throws PidUnknownException if the {@link Process} ID (PID) cannot be determined.
  @see org.cp.elements.lang.Identifiable#getId()
  @see org.cp.elements.process.util.ProcessUtils#findPidFile(File)
  @see org.cp.elements.process.util.ProcessUtils#readPid(File)
  @see #getDirectory()