Glossary
This is a glossary of OSA terms. Each entry has a brief definition, a
link to the main defining page, and links to related terms. A list of
symbols used in the graphical representation of OSA models is in the
symbolary.
- Access Interaction
- An
access interaction is a shorthand for a bidirectional interaction with the
system being modeled. It is used to obtain information about objects, usually
regarding relationships and related objects.
- Action
- An action is a process in states or
a procedure in transitions that
allow states or transitions to do some processes.
- Add Interaction
- An add interaction adds an object that already exists in the model
to an object class. See also the create
interaction.
- Aggregation
- Aggregation models the is subpart of relationship set. It is used when one object class is made up of one or more component object classes.
- Association
- Association models the is member of relationship set. It is used when one object class is a set of objects from another object class.
- Bidirectional Interaction
- A bidirectional interaction is used when there are two one way interactions that are so closely related that they can be treated as being the same interaction.
- Cardinality Constraint
- See Object-class Cardinality
Constraint.
- Condition
- A condition is a logical statement about the state of the system, the state or existence of an object, or the existence of relationships between objects.
- Condition-Based Trigger
- See Condition.
- Constraint
- A constraint restricts possible occurences or allowable
combinations in relationship sets, interactions, object
classes, etc. There are
Co-occurrence Constraints,
Object-class Cardinality
Constraints,
Participation Constraints, and
General Constraints.
- Continuous Interaction
- A continuous interaction is one where the origin object is continuously sending information to the destination object.
- Co-occurrence
Constraint
- A co-occurrence
constraint specifies the minimum and maximum number of
times an object or combination of
objects can co-occur in the
relationships of a
relationship set with
another object or combination of objects.
- See also Constraint,
Object-class Cardinality
Constraint, and
Participation Constraint.
- Create Interaction
- A create interaction creates a new obect in the model. See also the
add interaction.
- Destroy Interaction
- A destroy interaction causes an existing
object to cease to exist as far as the
analysis model is concerned.
- Event
- An event is a change within the system, including the creation or deletion of objects or relationships, the starting or stopping of an activity, and the reception of messages.
- Event-Based Trigger
- See Event.
- Exception
-
An exception is a system event or
condition which is not part of normal
system behavior. For example, a printer running out of paper
during a print job is an exception.
- Final Transition
- A final tansition is a transition with no
subsequent state conjunction.
- General
Constraint
- A general constraint specifies any information constraining
relationship
set which cannot be specified as
co-occurrence constraint,
object-class cardinality
constraint, or
participation constraint.
- Generalization
- A generalization is an object class
which is a superset of another object class (or classes).
Generalization models the is a relationship set since members
of the specialization class (or classes) are always members of the
generalization class. This means that members of the specialization
class have all of the same properties of the generalization class
including relationships with other objects as well as behaviour.
Therefore, specialization plays an important role in the ORM, OBM, and
the OIM.
- See also Specialization.
-
High-Level Object Class
- A high-level object class is an
object class that
contains other object classes,
relationship sets,
constraint, and
notes.
- High-Level Interaction
- A high-level interaction is an interaction that is an abstraction of lower level interactions, objects, object classes, general interactions constraints, and notes.
- High-Level
Object Class
- A high-level object class is an object class that contains other object classes, relationship sets, constraints, and notes.
-
High-Level Relationship Set
- A high-level relationship set is a
relationship set that
is an abstraction containing other relationship sets,
object classes,
constraint, and
notes.
- High-Level State
- A high-level state is a state that is an abstraction of lower level states, transitions, constraints, and notes.
- High-Level Transition
- A high-level transition is a transition that is an abstraction of lower level transitions, states, constraints, and notes combined.
- High-Level View
- A high-level view is the view of an interaction with the "internal" details omitted.
- Homonym
- When two object classes appear in the
model with the same name, these are considered the
same object class.
- See also Synonym.
- Initial Transition
- An initial transition is a transition that
has no prior state conjunction on it.
- Interaction
- An interaction is any inter-object communication. It can be thought of as a
message between the participating objects.
- Intersection Constraint
- An intersection constraint is used when a
specialization object class
has more than one generalization object class and
shows that the specialization object class is the intersection of the
generalization object classes. In other words, any object in all of the
generalizations is also in the specialization.
- Lexical Object Class
- A lexical object class is a class whose members have a one-to-one mapping to their representation.
- Membership Condition
- A membership condition is a
constraint imposed on the object class by the
ORM. To be a member of an object class, an
object must satisfy the membership conditions for
that class. Over time, an object may be a member of different object classes.
This is referred to as class migration.
- Modify Interaction
- A modify interaction is an interaction that update some data in object.
- Mutual Exclusion
Constraint
- The mutual exclusion constraint indicates that the
specialization object classes
are pairwise disjoint. In other words, no
object
can be a member of more than one specialization object class.
- Notes
- Notes are explanatory text added to diagrams. They have no
semantic significance to the model.
- Object
- An object is any unique thing such as a person, place, or any
physical or conceptual thing.
- Object Class
- An object class is a set of objects
that have shared properties.
- Object-Class Cardinality
Constraint
- An object-class cardinality constraint restricts the number of
objects in an
object class.
- See also Constraint,
Co-occurrence
Constraint, and
Participation Constraint.
- Participation
Constraint
- A participation constraint defines the number of times an
object in an
object class
can participate in a connected
relationship set.
- See also Constraint,
Co-occurrence
Constraint, and
Object-Class
Cardinality Constraint.
- Partition Constraint
- The partition constraint indicates that every
object in a
generalization object class must also
be a member
of at least one of the specialization
object classes, and that the specialization object classes are
pairwise disjoint.
- Path Marker
- A path marker is used to apply a real-time constraint
to a part of a state net. They are shown on the diagram as identifiers in
braces ("{}") placed along directed arrows.
- Prior State
- A prior state is a state which preceeds a
transition. A state may be a prior
state of some transitions and a subsequent state of others.
- See also Subsequent State.
- Prior State Conjunction
- A transition may require more than one
state to be on before it begins. The set of prior states which
must be on is a prior state conjunction.
- See also Subsequent State Conjunction.
- Real-Time Constraint
- A real-time constraint is a maximum time in which something should be
completed. Real-time constraints are shown in diagrams inside braces
("{}") and may be applied to states,
triggers, actions, entire
transitions, or state nets (using
path markers).
-
Relational Object Class
- An object class which contains
relationship sets. Shown on
diagrams by drawing an
object class rectangle around a
relationship set and all participating object classes.
- Relationship
- A relationship establishes a logical connection among objects.
- Relationship
Set
- A relationship set is a set of similar relationships.
- Remove Interaction
- Remove deletes an object from an object class, but not necessarily from the analysis model.
- Role
- A role is a shorthand way of expressing a specialization.
- Specialization
- A specialization is an object class
which is a subset of another object class (or classes).
Specialization models the is a relationship set since members
of the specialization class (or classes) are always members of the
generalization class. This means that members of the specialization
class have all of the same properties of the generalization class
including relationships with other objects as well as behaviour.
Therefore, specialization plays an important role in the ORM, OBM, and
the OIM.
- See also Generalization.
- Synonym
- Synonyms are multiple names for a single
object class. These are shown in
the object class rectangle,
separated by a vertical bar ("|").
- State
- A state is the status, phase, situation, or activity of an object at any given point in time.
- State Net
- A state net is the representation of the states of an object and the flow of control within an object or between objects.
- Subsequent State
- A subsequent state is a state which follows a
transition. A state may be a prior
state of some transitions and a subsequent state of others.
- See also Prior State.
- Subsequent State
Conjunction
- A transition may turn on more than one
state when it finishes. The set of subsequent states which
are turned on is a subsequent state conjunction.
- See also Prior State Conjunction.
- Thread
- A thread is a flow of control or execution within an object's behavior.
- Time-constrained Interaction
- A time-constrained interaction is a time-critical interaction that must take place in a specified finite amount of time.
- Transition
- A transition is how an object changes state.
Transitions consist of a trigger description, an action description, and an optional transition
identifier.
- Trigger
- A trigger is a combination of events and conditions which may activate a state transition.
- Union Constraint
- The union constraint indicates that every
object in a
generalization object class must also
be a member of at least one of the
specialization object classes.
Go to the
OSA Tutorial
Created Tue Sep 13 12:41:11 1994 ...
Updated
Wed Nov 23 13:38:19 1994
by Paul E. Black
(black@lal.cs.byu.edu)