Information Technology Reference
In-Depth Information
An activity diagram focuses on the flow of activities involved in a single
process. Collaboration diagrams are another form of interaction diagram, which
focuses on object roles to describe a process. Component diagrams are physical
analogs of class diagrams, that is, they convey the actual distribution of a software
system across physical computer systems. Deployment diagrams show the con-
figuration of run-time processing nodes. An interface is a collection of operations
that define the way in which an external entity is to interact with a class or
package. A package is a collection of model elements. A note is simply a symbol
for relaying useful information about a UML model.
3.7 Exercises
1. Last chapter, we asked you to explain the difference between a class and an
object using examples. Now, present the same difference, this time using
models.
2. Think yet again about the
truck
class and its
vehicle
superclass that we
have used throughout this topic. Create a different subclass of
vehicle
with
at least two unique attributes and two unique methods. Finally, create an
instantiation (object) of this new class. Diagram your new class, depicting its
relationship with the
vehicle
superclass and the object you chose to create.
3. Consider the following sequence involved in starting the
monster_truck
object:
Step 1: Insert
key
into
ignition
and turn. Sends message to …
Step 2:
ignition_controller
performs calculations and sends message
to …
Step 2.1:
fuel_injector
injects fuel [if there is
fuel
] and sends message
to …
Step 2.2:
spark_plug
ignites [if there is
power
] and sends message to…
Step 3:
piston
, at which point the monster truck is started and the
igni-
tion
reverts back to its initial state.
At each step in this sequence, an object performs an action, and then sends
some message to the next object in the sequence. In the second step, a fork is
initiated and two separate transitions appear next, which then join again in the third
step. Each parallel process initiated after step two checks for some condition
(contained in brackets ([])), which must be true for the sequence to continue on. If
these conditions are met, the
piston
reacts. If not, it remains static. In either
case, the sequence ends after this step, when the
ignition
reverts to its inactive
state. Illustrate this sequence using a sequence diagram.
