There a 2 hasValue methods in DataHolder:

• hasValue that returns true if there is a value, even empty
• and hasNonEmptyValue that returns true if there is a non empty value, and false otherwise

The most common use case is to figure out if there is a non empty value, so we should change these methods to have:

• hasValue that returns true if there is a non empty value, and false otherwise
• and hasValueOrEmpty that returns true if there is a value, even empty