code: private StringBuilder sourceControl(StringBuilder mapping){
  		
  		if(getMts() == ALL_FIELDS && !sourceType().isPrimitive()){
  			StringBuilder write = write("   if(",getSource(),"!=null){",newLine,
  										      sharedCode(mapping)	   ,newLine,
  										"   }");
  			
  			if(!destinationType().isPrimitive() && !avoidSet)
  					write.append(write("else{"					   ,newLine,
  										 setDestination("null")    ,newLine,
  										"   }"					   ,newLine));
  			else    write.append(newLine);
  			
  			return write;
  		} 
  		else return write(sharedCode(mapping),newLine);
  	}
docs: This method is used when the MappingType of Source is setting to ALL.
  @param mapping
  @return a StringBuilder that contains the mapping enriched with source controls