Unified Modeling Language User Guide Section 1—Getting Started

Unified Modeling LanguageUser Guide

Section 1—Getting Started

Paper

• Konsep Object dan Class

• Intro UML

• Enrollkey: pbotik-h

• Minngu depan – Review intro UML– Object oriented modeling

Sung Kim CS6359 Slide 2


Overview• Why we model

– Importance– Principles– Object-oriented modeling

• Introducing UML– UML Overview– Conceptual model of UML– Architecture– Software development life-cycle


What is a model?

• A model is a simplification of reality.

• A set of blueprints of a system.

• Semantically closed abstraction of the system.

• A model is an abstraction of something for the purpose of understanding it before building it.


Why We Model

• Communicate a desired structure and behavior of a software system.

• Visualize and control a system’s architecture.• Assist in understanding a system under

development.• Expose opportunities for simplification and

reuse.• Manage risk.• Document decisions.


Importance of Modeling

• Proven and accepted engineering technique; divide-and-conquer.

• We build models of complex systems because we cannot comprehend such a system in its entirety.

• Desire to build the right software right.


Principles of Modeling

1. The choice of what models to create has a profound influence on how a problem is attacked and how a solution is shaped.

2. Every model may be expressed at different levels of precision.

3. The best models are connected to reality.4. No single model is sufficient. Every

nontrivial system is best approached through a small set of nearly independent models.


Modeling Comparison

• Functional– Algorithmic perspective– Building blocks of functions or procedures– Yields brittle systems

• Object-Oriented– Building blocks of classes or objects.– Drawn from the vocabulary of the problem

space.


Object vs. Class

• Object– Thing drawn from the problem domain or

solution space.– Instantiation of class.– Has identity, state, and behavior.

• Class– Description of a set of common objects.


Introducing UML

• Used to visualize, specify, construct, and document

• …appropriate for modeling systems ranging from enterprise information systems to distributed Web-based applications and even to hard real time embedded systems.

• Process independent.


UML is a Language

• Vocabulary and rules for communication.

• Focus on conceptual and physical representations of a system.

• A language for software blueprints.

• Not a process.


A UML Compatible Process

• Use case driven

• Architecture-centric

• Iterative

• Incremental


UML is for Visualizing

• An explicit model facilitates communication.

• UML is a graphical language.

• UML symbols are based on well-defined semantics.


UML is for Specifying

• Specifying means building models that are:– Precise– Unambiguous– Complete

• UML addresses the specification of all important analysis, design, and implementation decisions.


UML is for Constructing

• Models are related to OO programming languages.

• Round-trip engineering– Forward engineering—direct mapping of a

UML model into code.– Reverse engineering—reconstruction of a

UML model from an implementation.– Requires tool and human intervention to

avoid information loss.


UML is for Documenting

• Architecture

• Requirements

• Tests

• Activities– Project planning– Release management


Conceptual Model of UML

• Three basic building blocks of UML– Things—abstractions that are first class

citizens in a model.– Relationships—tie things together.– Diagrams—group interesting collections of

things.


Things

• Structural—nouns of UML models.

• Behavioral—dynamic parts of UML models.

• Grouping—organizational parts of UML models.

• Annotational—explanatory parts of UML models.


• Nouns of UML models.

• Conceptual or physical elements.

• Seven Kinds

Structural Things

– Classes– Interfaces– Collaborations– Use cases

– Active classes– Components– Nodes


Classes

• Description of a set of objects that share the same attributes, operations, relationships, and semantics.

• Implement one or more interfaces.

Windoworiginsize

open()close()

nameattributes

operations


Interfaces

• Collection of operations that specify a service of a class or component.

• Describes the externally visible behavior.

<<interface>>

IWindow

open()close()

name

operations

IWindow


Collaborations

• Defines an interaction.

• Society of roles and other elements.

• Provide cooperative behavior.

• Structural and behavioral dimensions.

Chain ofresponsibility


Use Cases

• Description of a sequence of actions that produce an observable result for a specific actor.

• Provides a structure for behavioral things.

• Realized by a collaboration.

Place order


Active Classes

• Special class whose objects own one or more processes or threads.

• Can initiate control activity.

Event Manager

suspend()flush()

nameattributes

operations

heavyborder


Components

• Physical and replaceable part.

• Conforms to a set of interfaces.

• Physical packaging of logical components.


Node

• Physical element that exists at run time.

• Represents a computational resource.

• Generally has memory and processing power.

Node


Variations on Structural Things

• Actors

• Signals

• Utilities

• Processes and Threads

• Applications

• Documents

• etc.


• Verbs of UML models.• Dynamic parts of UML models.• Usually connected to structural elements.• Two kinds

– Interactions—behavior that comprises a set of messages exchanged among a set of objects.

– State Machines—specifies the sequences of states an object or interaction goes through in response to events.

Behavioral Things

display

Idle


Grouping Things• Organizational parts of UML.

• Purely conceptual; only exists at development time.

• One kind– Package—general-purpose mechanism for

organizing elements.

Business rules


Annotational Things• Explanatory parts of UML.

• Comments regarding other UML elements.

• Information best expressed as text.

• One kind– Note—symbol for rendering constraints or

comments attached to an element.

Return copy of self


Relationships in UML

• Dependency

• Association

• Generalization

• Realization


Relationships• Dependency—semantic relationship

between two things in which a change to one thing may affect the semantics of the other.

• Association—structural relationship that describes a set of links; a link being a connection among objects.

0..1 *

employer employee


Relationships (cont’d)

• Generalization—specialization relationship in which child objects are substitutable for the parent.

• Realization—semantic relationship between classifiers, wherein one classifier specifies a contract that the other guarantees to carry out.


Diagrams

• Graphical representation of a set of elements.• Rendered as a connected graph

– Vertices are things.– Arcs are behaviors.

• Projection into a system form a specific perspective.

• Five most common views built from nine diagram types.


Common Diagram Types

• Class• Object• Use case• Sequence• Collaboration

• Statechart• Activity• Component• Deployment


Rules of UML• Well formed models—semantically self-

consistent and in harmony with all its related models.

• Semantic rules for:– Names—what you can call things.– Scope—context that gives meaning to a name.– Visibility—how names can be seen and used.– Integrity—how things properly and consistently

relate to one another.– Execution—what it means to run or simulate a

dynamic model.


Models in Development

• Elided—certain elements are hidden for simplicity.

• Incomplete—certain elements may be missing.

• Inconsistent—no guarantee of integrity.

UML encourages the most important aspects such that models become well-formed over time.


Common Mechanisms in UML

• Specifications—textual statement of the syntax and semantics of a building block.

• Adornments—other details attached to UML elements.

• Common divisions—dichotomy representation of elements (i.e. Class vs. Object)


Common Mechanisms (cont’d)

• Extensibility mechanisms– Stereotypes—extends vocabulary.– Tagged values—extends properties of

UML building blocks.– Constraints—extend the semantics of UML

building blocks.


Architecture

• Set of significant decisions regarding:– Organization of a software system.– Selection of structural elements and

interfaces from which a system is composed.

– Behavior or collaboration of elements.– Composition of structural and behavioral

elements.– Architectural style guiding the system.


Architecture Views

Deployment ViewProcess View

Design ViewImplementation

View

Use Case View

vocabularyfunctionality

performancescalability

throughput

behavior

system assemblyconfiguration mgmt.

system topologydistributiondeliveryinstallation


Use Case View

• Encompasses the behavior as seen by users, analysts and testers.

• Specifies forces that shape the architecture.• Static aspects captured in use case

diagrams.• Dynamic aspects captured in interaction

diagrams, statechart diagrams, and activity diagrams.


Design View

• Encompasses classes, interfaces, and collaborations that define the vocabulary of a system.

• Supports functional requirements of the system.

• Static aspects captured in class diagrams and object diagrams.

• Dynamic aspects captured in interaction diagrams, statechart diagrams, and activity diagrams.


Process View

• Encompasses the threads and processes defining concurrency and synchronization mechanisms.

• Addresses performance, scalability, and throughput.

• Static and dynamic aspects captured as in design view; emphasis placed on active classes.


Implementation View

• Encompasses components and files used to assemble and release a physical system.

• Addresses configuration management.• Static aspects captured in component

diagrams.• Dynamic aspects captured in interaction

diagrams, statechart diagrams, and activity diagrams.


Deployment View

• Encompasses the nodes that form the system hardware topology.

• Addresses distribution, delivery, and installation.

• Static aspects captured in deployment diagrams.

• Dynamic aspects captured in interaction diagrams, statechart diagrams, and activity diagrams.


Software Process

• Use case driven—use cases are primary artifact for defining behavior of the system.

• Architecture-centric—the system’s architecture is primary artifact for conceptualizing, constructing, managing, and evolving the system.

• Iterative and incremental—managing streams of executable releases with increasing parts of the architecture included.


Phases

• Span of time between two major milestones.• Primary phases

– Inception—seed idea is brought up to point of being a viable project.

– Elaboration—product vision and architecture are defined.

– Construction—brought from architectural baseline to point of deployment into user community.

– Transition—turned over to the user community.


Summary• Modeling.

• UML introduction.

• Building blocks of UML.

• Rules of UML.

• Common UML mechanisms.

• Architectural views.

• Software lifecycle.