How to model validation rules and messages?

[Werner Schoenmaekers]

We have a classes "Car" and "Wheel", they are connected with an association.
"Car" has attribute "Fuel tank" of type integer.  It must be between 1 and 100 liters.

Questions:
- Where and how do model the "between 1 and 100" rule?
- Where do I model the message which must be shown to the user if he enters f.e. 200.

The goal is to generate a document where we have:

Class: Car
Association Wheel
Attribute: Fuel tank
    Constraint: between 1 and 100
    User message: "Please enter a value between 1 and 100".

How this is shown in the document is less important ( how many columns etc... ), but these 3 specs must be shown under "Car".

[Eve]

From the description you've given (and assuming you're not otherwise using Attribute Constraints) I would put it on the Attribute Constraints using the Description as the User message.