public Double extractAmount(XAttribute attribute) {
		XAttribute attr = attribute.getAttributes().get(KEY_AMOUNT);
		if (attr == null) {
			return null;
		} else {
			return ((XAttributeContinuous) attr).getValue();
		}
	}
public Double extractAmount ( XAttribute attribute ) { XAttribute attr = attribute . getAttributes ( ) . get ( KEY_AMOUNT ) ; if ( attr == null ) { return null ; } else { return ( ( XAttributeContinuous ) attr ) . getValue ( ) ; } }
Retrieves the cost amount for an attribute, if set by this extension's
amount attribute.

@param attribute
Attribute element to retrieve cost amount for.
@return The requested cost amount.