Midterm Study - UML Sequence

Question 1

What is a sequence (interaction) diagram?

Answer 1

Sequence diagrams show the explicit sequencing of messages. Showing the interactions between objects and flow of events in a single use case. It focuses on message details, used more frequently in industry. It is a depiction of the interaction among objects during certain periods of time.

Question 2

What does activation mean in a sequence diagram?

Answer 2

Activation is the time period during which an object performs an operation, represented by a thin rectangle on the lifeline of the object.

Question 3

What are messages in a sequence diagram?

Answer 3

Messages are means by which objects communicate with each other. Messaging is one of the defining features of the object oriented approach. Messages may hold value for objects to act upon.

Question 4

What are the three message types?

Answer 4

Synchronous Message: A type of message in which the caller (sender) has to wait for the receiving object to finish executing the called operation before it can resume execution itself Asynchronous Message: sender does not have to wait for receiver to complete called operation Simple Message: A message that transfers control from the sender to the recipient without describing the details of the communication

Question 5

What are the proper steps in developing a system sequence diagram?

Answer 5

1. Begin with detailed description of use case from fully developed form or activity diagrams. 2. Identify input messages 3. Describe message from external actor to system using message notation 4. Identify and add any special conditions on input message, including iteration and true/false conditions 5. Identify and add output return messages

Question 6

What does a first-cut sequence diagram look like?

Answer 6

Question 7

What does a partial three layer design look like?

Answer 7

Question 8

What does a complete three layer design look like?

Answer 8

Question 9

What are the 5 steps to draw a sequence diagram?

Answer 9

Step1: Define who will initiate the interaction

Step2: Draw the first message to a sub-system

Step3: Draw message to other sub-systems

Step4: Draw return message to actor

Step5: Send/Respond to anonymous actors