calling one function after another

hi guys

I have this code


public class PersonGrid extends VBox  
{
public var lookUp : PersonLookup = new PersonLookup() ;      

public function PersonGrid()
{

if (lookUp && lookUp.collection) {
Swiz.dispatchEvent(new ScreenEvent(ScreenEvent.PERSON_LOOKUP, Constants.DEFAULT_LOOKUP));
      }            
}


[Mediate(event="ScreenEvent.PERSON_LOOKUP_DATA_RECEIVED", properties="data")]
public function populateLookUp( data:Object ):void{
if (lookUp) {
lookUp.collection = data as ArrayCollection;
      }
}


public function setData(data:Object):void {
loadData(data);

     }
}


Currently setData(data) is called first and then populateLookUp() is called next.
My requirment is i want to check ONLY after populateLookUp() is called i want to call loadData();
Any idea how i can do that?            
thanks