adding properties to a custom components in Flex

I have a custom component and i want to add a property source[a property in the Flex property of lists, datagrids,trees]. so, i decided to checkout the one from the Adobe code.

it looks something like this :

public function g开发者_开发问答et source():XMLList
{
  return list? XMLListAdaptor(list).source : null;
}

public function set source():void
     {
      if(list)
      XMLListAdaptor(list).source = null;
     list = new XMLListAdaptor(s);
     }

now, I am interested in how to use the Adobe property in my custom component?