Requirements  

Engineering

"Basic Patterns"

Software Engineering

​Dr. Jose María Alvarez-Rodríguez

Examples of Patterns

• No unique

• No all

• They should be adapted depending on the  context

  • Domain
  • Requirement type
  • ...

• They need a domain vocabulary: concepts and relationships

• ...

Pattern #1

<system>  shall <action> 

• The <system> can be the whole system, a subsystem or a component.
  • Car, braking subsystem, brake pedal, etc.
• The action or capability  in simple future.

The car  shall speed up.

Pattern #2

<sytem> shall <action> <entity>

The car  shall brake when the brake pedal is pressed

Pattern #3

<system> shall allow <entity> to be  <state_X>

• ...
• The <state_X> represents a domain verb or concept.

The car shall allow the engine to be idle.

Pattern #4

<system> shall be <entity>

The car  shall be idle.

Pattern #5

<system> shall have <entity>

The car shall have a brake pedal.

Pattern #6

<system> shall have <quality_factor>  

by at least <quantity> <unit>

The heating subsystem shall have an availability

by at least 4 hours.

• Magnitude and unit of measurement

Pattern #7

<system> shall have <quality_factor>  

of a maximum <quantity> <unit>

The heating subsytem  shall have an availability of a maximum  6 hours.

Pattern #8

<system> shall not <action>​ 

• Negative requirements! (potentially infinite!)

The car shall not hibernate.

Pattern #9

<system> shall not <action> <entity>

The car shall not speed up when the brake pedal is pressed.

Pattern #10

<system> shall not allow <entity> to be in  <state_X>

The car shall not allow drivers to be driving without the seat-belt.

Pattern #11

<system> shall not allow  <action> <entity>

The car shall not allow changes in the engine controller.

Pattern #12

<user> shall be able to perform <action>

The driver shall be able to change the gear manually.

Pattern #13

<system> shall be in <state_X> <quantity> <unit>

The engine shall be in idle state after 5 minutes.

...more patterns?...

Design

• Domain
• Need
• Vocabulary
• Type of requirement
• ...

Credits

• CESAR (Cost-efficient methods and processes for safety relevant embedded systems) Project, entregable D_SP2_R3.3_M3_Vol2: http://www.cesarproject.eu/

• Requirements Quality Suite. The Reuse Company Inc.