Array assignment problems

Public & nbsp; function & nbsp; setParm ($ parameter, & nbsp; $ value) & nbsp ;{$ this-& gt; parameter [$ parameter] & nbsp; $ value; return & nbsp; $ this;} function & nbsp; geturl ($ type) {& nb array assignment

public function setParm($parameter, $value) {
$this->parameter[$parameter] = $value;
return $this;
}

function geturl($type){
     $this->setproductparm($type);
     return $this->getData();
     }  
   
private function setproductparm($urltype){
     $this->parameter=array();
     $this->type="";
     $this->setParm("Marketplace",self::marketplaceId);
     $this->version="2009-01-01";
     switch ($urltype){
        case "RequestReport":    
            $this->setParm("Action","RequestReport");
            $this->setParm("ReportType","_GET_MERCHANT_LISTINGS_DATA_");
        break;
        case "GetReportList":  
            $this->setParm("Action","GetReportList");   
            $this->setParm("ReportRequestIdList.Id.1",$this->ReportRequestId);
        break;
        case "GetReport":  
            $this->setParm("Action","GetReport");   
            $this->setParm("ReportId",$this->ReportId);  
        break;   
          
              
        }
        
     }

$ Url1 = $ aa-> geturl ("RequestReport ");
$ Url2 = $ aa-> geturl ("GetReportList ");
$ Url3 = $ aa-> geturl ("GetReport ");

I clearly cleared the array before each execution.
$ This-> parameter = array ();
However, in the output, each array contains the value assigned last time.
Results:
$ Url1: ReportType = _ GET_MERCHANT_LISTINGS_DATA _
$ Url2: ReportType = _ GET_MERCHANT_LISTINGS_DATA _ & ReportRequestIdList. Id.1 = 123456
$ Url3: ReportType = _ GET_MERCHANT_LISTINGS_DATA _ & ReportRequestIdList. Id.1 = 123456 & ReportId = 123456

Where is the problem ???
------ Solution ----------------------
You have not defined getData.
------ Solution ----------------------

// Check if the following method is correct.
GetData ();