function __construct($BaseURI, $TraceName, $TraceSourceName, $ModelURI)
 {
     $this->TraceName = $TraceName;
     $this->BaseURI = $BaseURI;
     $this->TraceSourceName = $TraceSourceName;
     $this->TraceURI = $this->BaseURI . $this->TraceName;
     if ($ModelURI == null) {
         $trace = new Trace($this->TraceURI);
         $this->ModelURI = $trace->getModel();
     } else {
         $this->ModelURI = $ModelURI;
     }
 }