Definition

Properties describe a particular aspect of an Entity. A Property is defined by a name and a value, which can be limited to some field. There are two main types of Properties: numeric ones and non-numeric ones.

we haven't found some useful example where a 'null' value could be useful, so 'null' value is tested against.

Implementation:

abstract class Property { Property( String name) throws IllegalArgument; // IllegalArgument if null value final String getName(); Object getValue(); }