© Trygve Reenskaug 2003 7 November 2003:15:30. OO-NIK 2003 Slide 1 Objektorientering og Informasjonssystemer for det 21. århundre (Understand – Explore

© Trygve Reenskaug 2003 7 November 2003:15:30.OO-NIK 2003 Slide 1

ObjektorienteringObjektorienteringogog

InformasjonssystemerInformasjonssystemerfor det 21. århundrefor det 21. århundre

(Understand – Explore – Master – Control)(Understand – Explore – Master – Control)

Trygve Reenskaug IfI, UiO

[email protected]://www.ifi.uio.no/~trygver

NIK 2003Oslo. 25 november 2003


The Invention ofThe Invention ofObject OrientationObject Orientation

C++

C MultiProcessE-RLispAugmentAlgol-60 Objects

Simula I

Simula 67

Java

Smalltalk-72 -76 -78 -80

RoleModeling

UML 1.x

IS21c-Information Systems for the 21st Century

UML 2.0Squeak


Simula…Simula…A system description languageA system description language

By a system we mean a collection of components which are either

• acting upon other components,

• being acted upon,

• or mutually interacting…"

SIMULA BEGIN:


SIMULA SIMULA BEGINBEGINfig. 1.1.2fig. 1.1.2

SYSTEM LANGUAGE

SYSTEMDESCRIPTION

MODEL

PERSONI

I

I

IA

A

I: Information transferA: Actions


SIMULA SIMULA BEGINBEGIN (1973)(1973)

Example: A Post Office SystemExample: A Post Office System

COUNTER

POST OFFICE

DOORCOUNTERCOUNTERCOUNTER

COUNTER

CLERKQUEUECUSTOMER

CARRY OUTALL TASKS

LIST OFTASKS

CUSTOMER

LIST OFTASKS

CARRY OUTALL TASKS

CUSTOMER

CARRY OUTALL TASKS

LIST OFTASKS


The small, but significant, differenceThe small, but significant, differenceProcedure OrientedProcedure Oriented

PlannerClient

norm_frontload

(…)

activityAduration...

start…end...

activityBweight...duration...

start…end...

activityCweight...duration...

start…end...

activityFduration...

start…end...

crane_frontload

(…)

[ Brad Cox 87]


The small, but significant, differenceThe small, but significant, differenceObject OrientedObject Oriented

PlannerClient

activityAduration...

start…end...

activityBweight...duration...

start…end...

activityCweight...duration...

start…end...

activityFduration...

start…end...

[ Brad Cox 87]

fron

tload

(time)

frontload(…)

frontload(…)


Two ApproachesTwo Approachesto Object Orientationto Object Orientation

• "East Coast Approach":Object orientation is a smart programming artifact. An object is an instance of a class.

• "West Coast Approach": Object Orientation is a powerful tool for thinking. An object is an entity with a well-defined boundary and identity that encapsulates state and behavior without revealing its interior construction.


TO-CTO-BTO-CtoBtoC

toC

The Clerk metaphorThe Clerk metaphorfor Object Orientationfor Object Orientation

IN

Methods Data

Object A Object B

IN

Methods Data

Port

Messagetriggers method

causes response

Message

StateBehaviorIdentityEncapsulationPolymorphismCommunication (Collaboration)

Inheritance

Data

Object C

IN

Methods

Message

Message


The Idea: Records --> ObjectsThe Idea: Records --> ObjectsSome relevant shipyard objectsSome relevant shipyard objects

Object representinga ship's part

Object representinga construction activity

Object representinga resource

Object representingthe shipyard resources

Object representingthe Shipyard

Object representing a ship’s schedule


SmalltalkSmalltalk

C++

C MultiProcessE-RAlgol-60 Objects

Simula I

Simula 67

Java

RoleModeling

UML 1.x


UML 2.0Squeak

LispAugment

Smalltalk-72 -76 -78 -80


Alan Kay's DynabookAlan Kay's DynabookOwner can view, navigate, edit objectsOwner can view, navigate, edit objects


SmalltalkSmalltalkPersonal Information EnvironmentPersonal Information Environment


Smalltalk-78 in OsloSmalltalk-78 in Oslowith Else Nordhagenwith Else Nordhagen


Objective C, C++ , JavaObjective C, C++ , Java

C++


Simula I

Simula 67

Java

RoleModeling

UML 1.x


UML 2.0Squeak

LispAugment

Smalltalk-72 -76 -78 -80


Role Modeling / Role Modeling / OOramOOramActivity ObjectsActivity Objects

C++


Simula I

Simula 67

Java

RoleModeling

UML 1.x


UML 2.0Squeak

LispAugment

Smalltalk-72 -76 -78 -80


The original 1979 MVCThe original 1979 MVCThe The TOOL AS A COMPOSITETOOL AS A COMPOSITE

ComputerModel

Editor

ToolMentalModel

User

View

Controller


UML 1.xUML 1.x

C++


Simula I

Simula 67

Java

RoleModeling

UML 1.x


UML 2.0Squeak

LispAugment

Smalltalk-72 -76 -78 -80


public class Activity {protected String name;protected int duration;protected int earlyStart;protected int counter = 0;private Activity[] successors;… … …public void frontLoad (int time ) {

earlyStart = Math.max (earlyStart, time);if ((counter += 1) >= predecessors.length) {

int fin = getEarlyFinish();for (int i=0; i<successors.length; i++) {

successors[i].frontLoad(fin+1);}

}}… … …

}

public class Activity {protected String name;protected int duration;protected int earlyStart = 0;protected int counter = 0;private Activity[] successors;… … …public void frontLoad (int time) {

earlyStart = Math.max (earlyStart, time);if ((counter += 1) >= predecessors.length) {

int fin = getEarlyFinish();for (int i=0; i<successors.length; i++) {

successors[i].frontLoad(fin+1);}

}}… … …

}

Java class definition:Java class definition: ActivityActivity


ActivityActivityUML cUML class modellass model

Activityint duration;int earlyStart;int counter;

void frontLoad (int time);int getEarlyFinish();

*

*

successors


ActivityActivityUML UML class hierarchy modelclass hierarchy model

Activityduration: intearlyStart: intcounter: int

frontLoad (int time): voidgetEarlyFinish(): int

0..*successors

0..*

NormalActivityresource: NormalResource

/ getEarlyFinish(): int

CraneActivityresource: CraneResourceload: int

/ getEarlyFinish(): int


* *

The essence of frontloadingThe essence of frontloadingCommunication Communication

Pred Act Succ1: fL(t1) 2: fL(t2)


* *

The essence of frontloadingThe essence of frontloadingCommunication DiagramCommunication Diagram

Pred Act Succ1: fL(t1) 2: fL(t2)


Specialization of CollaborationSpecialization of CollaborationFrontloading with resourcesFrontloading with resources

1: fL(t1) 2: fL(t2)

* *Pred / Activity Succ

1.2: reserv()1.1: alloc()1

*Res

Act


Interfaces in theInterfaces in theBasic scheduling collaborationBasic scheduling collaboration

Pred Act Succ

The interfaces specify minimal requirementsto receiving objects

«Interface»FrontloadIntf

frontLoad(t)

fL(t1) fL(t2)


UML 2.0UML 2.0 (Now being finalized)(Now being finalized)

C++


Simula I

Simula 67

Java

RoleModeling

UML 1.x


UML 2.0Squeak

LispAugment

Smalltalk-72 -76 -78 -80


UML 2.0 Proposal: UML 2.0 Proposal: Components, Parts, Ports, LinksComponents, Parts, Ports, Links

From partners' presentation to OMG Nov 2001 (With permission)


? UML 3.0 ?? UML 3.0 ?An Executing System EnvironmentAn Executing System Environment

C++


Simula I

Simula 67

Java

RoleModeling

UML 1.x


UML 2.0Squeak

LispAugment

Smalltalk-72 -76 -78 -80


#User's model of the application•utility - cause and effect

#Architect's model of the running system•objects - containment - roles - responsibilities•behavior - interactions - state machines - actions

#Coder's model of the code•classes - features - inheritance - packages - deployment

We create system modelsWe create system modelsto master our environmentto master our environment

#User's model of the application•utility - cause and effect

#Architect's model of the running system•objects - containment - roles - responsibilities•behavior - interactions - state machines - actions

#Coder's model of the code•classes - features - inheritance - packages - deployment






Thank YouThank You

http://ifi.uio.no/~trygverMore info at


More details ….More details ….• http://www.ifi.uio.no/~trygver [email protected]

• Unified Modeling Language (UML). Object Management Group. Version 2.0, Final Adopted specification

http://www.omg.org/techprocess/meetings/schedule/MOF2-UML2_Infrastructure_FTF.htmlhttp://www.omg.org/techprocess/meetings/schedule/UML_2.0_Superstructure_FTF.html

• Roles and artifacts in cognitive psychology:Steven Pinker: How the Mind Works. Norton, New York 1997. ISBN 0-393-04535-8

• The reference work on role modeling: Reenskaug, Wold, Lehne: Working With Objects. This book is out of print. A .pdf version kan be downloaded free from http://www.ifi.uio.no/~trygver

• The theory of role modeling: Egil P. Andersen: Conceptual Modeling of Objects. A Role Modeling Approach. Dr Scient thesis. Dept. of Informatics, University of Oslo. 4 November 1997. ftp://ftp.nr.no/pub/egil/ConceptualModelingOO.ps.gz

• Richard Pawson and Robert Matthews: Naked Objects.See http://www.nakedobjects.org

Documents

© Trygve Reenskaug 2003 7 November 2003:15:30. OO-NIK 2003 Slide 1 Objektorientering og Informasjonssystemer for det 21. århundre (Understand – Explore