• Logical view– show classes and objects

• Process view – models the executables

• Implementation view– Files, configuration and versions

• Deployment view– Physical and computational nodes

• Use-case view– Models the basic requirements

• 4+1 view

Architecture

• Highest level concept of the system and its environment

• Organizational structure of a system– Parts– Connectivity– Interaction– Mechanisms– Guiding principles

UML

• Program = Data + Algorithm

• Software System = Objects + Messages

• UML models the world as a system of interacting objects.

• An object is a cohesive cluster of data and function.

• UML is a visual language

Object Model

• Static Structure: Describes the important objects of the system and their relationships

• Dynamic Behavior: Describes the lifecycles of the objects and how and when they collaborate to deliver the system functionality

UML Structures

• Things – modeling elements

• Relationships – semantic relationship between the things

• Diagrams – representing the ‘what’ and ‘how’ of the system.

Things

• Structural things - class, interface, collaboration, use case, active class, component, node, etc.

• Behavioral things – interactions, sequence diagram, state machines

• Grouping things – package

• Annotations – notes, comments, etc.

Relationships

• Association

• Dependency

• Generalization

• Realization (use-case)

Diagrams

• Class diagram• Component diagram• Deployment diagram• Object diagram• Use-case diagram• Sequence diagram• Collaboration diagram• State chart diagram• Activity diagram

UML common mechanisms

• Specifications – textual descriptions of the semantics of an element – Meat of the model

• Without specs we just have blobs connected by lines

• Specs evolve over time – and hence may be incomplete and/or inconsistent

• Completeness and consistency test is applied periodically

Adornments

• Specs are hidden

• Important details are added to model

• Added only to highlight and add clarity

Classifier

• Abstract notion• Actor

– role played by outside user

• Class – description of similar objects

• Classifier role – restricted classifier

• Component – replaceable part of the system

• Datatype

• Interface– collection of operations to specify a service offered by

a class or a component

• Node– physical, run-time element

• Signal– an asynchronous message

• Subsystem– grouping of elements

• Use-case– sequence of actions performed to accomplish a task

• Instances are concrete things – taking part in the workings of the system

• Interfaces – present the contract for a functionality

• Various implementations can be made available to adhere to the interface.

• Constraints can be added to elements

• Stereotype is a tagged and/or constrained element