e3value user manual, first release

3.1 Value objects

A value object is a money- or non-money object that

Value objects should be countable, which means that it is meaningful to ask how many of them there are. Value objects have economic value, defined differently for money- and non-money objects.

A money object has a definite value that is known and agreed on by actors. If actor A pays f10 to actor B, then B receives f10 from A.1 Money objects are also called value-in-transfer  [6].

A non-money object may be a physical good (of the kind that you can touch or can drop on the floor), the outcome of a service, or an experience. The value of a non-money object for an actor depends on the increase in utility when the actor consumes or uses the value object. Different people may assign different value to non-money objects, and one person may even assign a different value at different times. For example, the value of a cold beer to me on a hot summer day is different from its value on a cold rainy day. The value of an non-money object is often called value-in-use [6].

A value object is represented by showing the name of the object next to a value transfer enclosed in square brackets (as [value object]). In figure 3.1, two value objects are represented: Money and Train trip. The name of a value object should express the economic utility of the object. It should explain why an object is of value to an actor.

All value objects have a valuation, which for money objects expresses the value in some currency. In this book we represent that currency by the symbol f, pronounced “Florin”.