The main concepts often act as objects existing more or less independently
from others. When adding more details, the focus generally moves from objects to
other kinds of language concepts such as their properties, connections in terms of
relationships, roles, or ports the objects may have in different connections, submodels,
and even links to other model elements expressed in other languages.
The selected language type (e.g., state machine) and its MOC help to determine
what kinds of additions are possible. You enrich the chosen base languages with
domain-speci?¬?c concepts and rules. To illustrate the use of alternative modeling
concepts, let??™s inspect another example from the watch case: Consider supporting a
new button pressing policy in the language. Instead of pressing a button only once to
start an operation in a watch, we have a new policy that is based on keeping the button
pressed for a longer time, like 3 seconds. How should that be expressed in the
language? It could have any of the following:
1. Its own modeling object: A long button press object in addition to the existing
short button press.
IDENTIFYING AND DEFINING MODELING CONCEPTS 241
2. A property of the current object: The current button concept in the language
can be speci?¬?ed as either a short press or a long press. If the short press is the
most typical case, the property could have the corresponding default value.
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