CS2002 - Week 5 - Sequence Diagrams

Question 1

Synchronous message

Answer 1

Sender waits until it has received a response message before continuing (close arrowhead)

Question 2

Asynchronous message

Answer 2

Sender continues without waiting for a response message (open arrowhead)

Question 3

Response message

Answer 3

May be omitted if content and location are obvious

Question 4

alt

Answer 4

alternative interaction, similar to switch statement in java, conditional branches with guards

Question 5

opt

Answer 5

optional interaction, similar to if statement without else branch

Question 6

loop

Answer 6

repeated interaction

Question 7

break

Answer 7

exception interaction, simple form of exception handling

Question 8

seq

Answer 8

weak order, interactions occur in strict sequence order

Question 9

strict

Answer 9

strict order, interactions occur in more restrictive order without parallelism or out-of-order execution, messages must follow vertical order

Question 10

par

Answer 10

concurrent interaction, allows parallel interactions, messages can interleave

Question 11

critical

Answer 11

atomic interaction, ensures interaction complete without interruption, messages can’t interleave

Question 12

ignore

Answer 12

irrelevant interaction, specifies messages that should be ignored and not shown in the diagram

Question 13

consider

Answer 13

relevant interaction, specifies which should be considered while ignoring others

Question 14

assert

Answer 14

asserted interaction, specifies an assertion that must always be true for sequence to proceed

Question 15

neg

Answer 15

invalid interaction

Question 16

Sequence diagram purpose

Answer 16

Shows interactions between objects in chronological order