Software Modeling

1
Software Modeling

• Andrew Sutton
• ltSDMLgt
• Department of Computer Science
• Kent State University

2
Overview

• What is software modeling?
• Why do we model software?
• Modeling past and present
• Modeling in the future
• Modeling Tools

3
Definition of Model

• A schematic description of a system, theory, or
  phenomenon that accounts for its known or
  inferred properties and may be used for further
  study of its characteristics a model of
  generative grammar a model of an atom an
  economic modelwww.dictionary.com

4
Definition of Software Model

• Software Model A description (textual or
  visual) of any aspect of a software system such
  as requirements, architecture, behavior,
  deployment the development process model, a
  requirements model, concurrency model.me
• Software Modeling The practice of creating and
  analyzing software models.me again

5
Examples of Software Models

• Development methodologies are models of how
  people collaborate to produce software.
• A system design is a model of the structure of
  classes or modules in a system's implementation.
• A flow chart visually models an algorithm's
  logic.
• Pseudo code textually models an algorithm's logic.

6
Why Do We Model Software?

• Several camps in modeling
• Those who use models to communicate about
  software
• Those who use models to validate software
• Those who use models to generate software

7
A History of Software Modeling

• Pseudo-code The orginal software model
• Has origins in mathematics
• Used to informally describe the behavior of
  algorithms using code-like constructs
• Flowcharts mid 20th century?
• Probably came from the business world
• Used to visually model processes, business logic

8
Modeling State and Sequence

• Statecharts mid 20th century?
• Specification Description Language (SDL) 1976
• Describes state machines, events and constraints
• Used by telecom industry to validate WAN protocol
  stacks
• Has both textual description language and visual
  representations

9
Modeling State and Sequence

• Message Sequence Charts (MCS) mid 80's
• Describes sequence of state changes and
  communications between objects/modules
• State machines don't show time ordering
• Extended MCS (EMCS) combines SDL, MCS for more
  accurate sequence modeling

10
Data Modeling

• Various data models late 60's to early 80's
• Network model, file system model, hierarchy model
• Entity-Relation Model Chen, 1976
• Formal definition of entities and relations
• Supercedes previous data models
• Entity-relation diagrams (ERD)

11
Object-Oriented Modeling

• OO Modeling (in general) starts in late 70's
• Typically associated with engineering
  methodologies
• Descriptive (not formal) visual representations
  of classes in a software system
• During the 80's number of OO modeling languages
  or techniques jumps from 10 to 50
• Modeling Language
• Set of elements used to pictorally represent ideas

12
Object Oriented Modeling

• Three personalities
• Grady Booch, Ivar Jacobson, James Rumbaugh
• Introduce engineering methodology with software
  modeling
• OMT Rumbaugh 1991
• Provides notation for static and dynamic software
  modeling (classes and behaviors)

13
Object Oriented Modeling

• OOSE Jacobson 1992
• Describes visual notation for use cases
  (requirements modeling)
• OOSE is a use case driven approach to
  engineering
• The Booch Method Booch 1993
• Combines different models for logical, physical,
  static and dynamic aspects of a system

14
The Origins of UML

• 1994 Booch, Rumbaugh join Rational, anounce
  merging of methodologies at OOPSLA
• 1995 Booch, Rumbaugh publish the Unified Method
  at OOPSLA, Jabson joins Rational
• 1996 The three amigos rename the Unified
  Method to the Unified Modeling Language

15
The Standardization of UML

• 1997 Rational proposes UML as a standard
  notation to the Object Management Group, UML 1.1
  adopted
• 2003 OMG publishes UML 1.5, most recent
  stable version of UML
• 2004 OMG publishes UML 2.0, the newest version
  of the standard

16
Who Is the OMG?

• Object Management Group
• Consortium of corporations collaborting on
  industry (not ISO) standards.
• Responsible for CORBA
• Who is involved?
• See next slide

17
OMG Members

• Borland
• DaimlerChrysler
• Computer Associates
• EDS
• Hewlitt Packard
• Sun Microsystems
• Fujitsu
• Raytheon
• Lockheed Martin
• W3C
• Boeing
• GNOME
• Motorola
• NEC
• Nokia

• Gentelware
• DARPA
• Bank of America
• France Telecom RD
• GE Transportation
• Honeywell
• GlaxoSmithKline
• Oracle
• Sandia National Laboratories
• NATO
• Arizona State University
• Ohio University
• Johns Hopkins University
• Syracuse University
• Kings College London

18
Modeling Now and Later

• Model Driven Architecture (MDA)
• Generate software through models (code
  generation, generative programming)
• Metamodeling
• Define or extend modeling languages for different
  purposes
• Model transformations, mappings, etc.