Aspect-Oriented Software Development with Use Cases

AspectJ Reference: Diagrams and materials based on “Aspect-Oriented Software Development with Use Cases” by I. Jacobson and P.-W. Ng, 2005, Addison-Wesley

More?

• http://www.early-aspects.net/

Use Cases – Basic Ideas

• Overview

Use Cases & Aspects

• So far, our aspects have been about non-functional concerns

• Observations:– a use case usually refers to a function that a user

does with the system; usually a set of use cases model functional requirements (application use cases)

– use cases can also be used to model non-functional requirements (infrastructure use cases)

– a use case is a user task or a concern– a use case (whether application or infrastructure)

could correspond to an aspect!

Figure 3-1(incompletelist of use cases)

Figure 3-2(incompletelist of use caserealizationsfor the system)

Application Use Cases

:

Use case slices

From Use Cases to AspectsFigure 1-2

Figure 2-1

1. public aspect CheckInCustomer {2. ...3. public void Room.assignCustomer ()4. {5. // code to check in customer6. }7. public void Reservation.consume()8. {9. // code to consume reservation10. }11. public void Payment.createBill()12. {13. // code to generate an initial outstanding bill14. }15. ...16. }

Figure 4-3

Extension

Figure 4-4

Figure 4-5

Extension – con’t

Figure 6-1

Figure 6-3

Use Case: Handle Waiting List

Basic Flows

. . .

Extension Flows

EF1.Queue For Room

This extension flow occurs after UpdatingRoomAvailability yields No Rooms Available.

The system creates a pending reservation with a unique identifier for the selected Room type.

The system puts the pending reservation into a waiting list.

The system displays the unique identifier of the pending reservation to the customer.

The base use case terminates.

Extension Pointcuts

extension pointcut UpdatingRoomAvailability = Reserve Room.Update Room AvailabilityFigure 6-5

Inclusion

Figure 6-6

Figure 6-8

Generalization

Figure 6-9

Application Use Cases and Infrastructure Use Cases - Example

Functionalreqs

Non-functionalreqs

Application Use Cases and Infrastructure Use Cases – Example – con’t

Relationship between applicationuse cases and infrastructure usecase? “binding”e.g., “<Perform Transaction>” binds to“Reserve Room” &“<Actor>” binds to “Customer”

Note: a template

Use Case Slice• A use case slice is collects together the parts of classes and

operations (as represented via aspects), and (whole) classes, that are specific to a use case.

• What follows?– Example of 2 Application Use Cases and their Use Case SliceFig 13-3,12-3,12-7, 13-4, 13-6(Jacobson & Ng)– Example of an Infrastructure Use Case SliceFig 14-4,14-5;14-9 (Jacobson & Ng)

Representing a Use Case Slice in “UML”

Representing Aspects in “UML”

(MoreIn handout-Appendix A)

Basic interaction diagram

Elaboratedinteraction diagramfor reservingroom

Example 1: use case slicefor room reservation

Use Case SliceFor “Reserve Room”Use Case

Elaboratedinteraction diagramfor reservingroom

Example 1: use case slicefor room reservation

Basic interaction diagram

Elaboratedinteraction diagramfor handling waiting list

Example 2: use case slicefor handle waiting list

Elaboratedinteraction diagramfor handling waiting list

Use Case SliceFor “HandleWaiting List”Use Case

Example: Infrastructure Use case slice forAdding authorization checks

Basic interaction diagram

Basic interactionDiagram extendedWith authorization calls

Use case slice for “Handle Authorization”

For each use case slice,define corresponding classes and aspects.Form the system byputting together use case slices +non-use case slices (not shown)…

Aspects and Architecture

Driving and Managing Architectural Decisions with Aspects, Garcia et al., 2006

Aspects and Architecture

Driving and Managing Architectural Decisions with Aspects, Garcia et al., 2006

Aspects and Software Product Lines

• There are kernel, optional, variant features in products

• “Extensions” can be modelled and implemented via aspects – variations localised in aspects

• On-going: e.g., http://ample.holos.pt/, http://www.softeng.ox.ac.uk/aople/