Agenda

• Design a Use Case
• Use Case Realization-Design
• Interaction Diagrams in Design
• Modeling Concurrency
• Subsystem Interactions

Design a Use Case

Use Case Realization-Design

• "Use case-realization-design" are collaborations of design objects and design classes that realize a use case.
• Use case realization in design will involve design classes, interfaces, and components rather than analysis classes.
• The process of creation of use case realizations in design is likely to uncover new non-functional requirements and new design classes.
• Use case realization-design help you find central mechanisms (e.g., database management) that are applied consistently throughout the system development.

Interaction Diagrams in Design

In design you may

• refine key analysis interaction diagrams, or
• create new ones to illustrate central mechanisms such as object persistence.

The analysis interaction diagram.

A typical sequence diagram for AddCourse use case in the early stage of design

• GUI (not modeled very deeply yet)
• operations specified to be implemented, explicit constructor
• persistence - central mechanism  for the whole application

Application Functional Components

Application Distribution Points?

Distribution Points

Software Architectural Patterns

• Data Flow Systems
  • Batch Sequential
  • Pipes and Filters
• Call and Return Systems
  • Main Program and Subroutines
  • Object-Oriented Systems
  • Hierarchical Layers
• Independent Components
  • Communicating Processes (C/S)
  • Event Systems
  • Service-oriented
  • P2P
• Data-Centered System
  • Transactional Database Systems (Repository)
  • Blackboards
  • Space-based (Tuple Spaces, JavaSpaces)
• Virtual Machines
  • Rule-Based Systems
  • Interpreters
  • JITs
  • Adaptive (HotSpot)
     

Distributed Architecture Rules

• cooperative distributed processing - distributed data, transaction, and workflow management
• fine granularity security
• local autonomy
• no reliance on central site
• continuous operation
• location transparency and location independence
• fragmentation independence
• replication independence
• distributed query processing
• hardware independence
• operating system independence
• network independence
• DBMS independence
• wrappers for existing applications
• simple is beautiful - object technology (cohesive components and loosely coupled)

Architecture and Reuse

What Kinds of Architectures Best Support Reuse?

Modeling Concurrency

Concurrency is one of the key consideration is design.

Concurrency support in UML 2

• active classes
• forks and joins in activity diagrams
• the par operation in sequence diagrams
• sequence numbers prefixes in communication diagram
• multiple traces in timing diagrams
• orthogonal composite states in state machines

Active classes

• Concurrency - each active object has its own thread.
• Active classes have instances that are active objects.
• Active objects and active classes are drawn as normal classes and objects but with double right and left borders as illustrated below.

Concurrency in sequence diagrams

• Combined fragments divide a sequence diagram into different areas with different behavior.
• par (parallel) - all operands execute in parallel.
• The diagram below demonstrates the use of the par, loop, critical, and opt operators.
  The critical operand executes atomically without interruption.

Concurrency in communication diagrams

Postfix the sequence number with a label to show different threads of control.

Subsystem Interactions

Subsystem interactions diagrams can show the interactions between parts of the system.

The interface CustomerManager is hanging below the subsystem.