Last Time: Object Design. Comp435 Object-Oriented Design. Last Time: Responsibilities. Last Time: Creator. Last Time: The 9 GRASP Patterns
|
|
- Abraham Walton
- 6 years ago
- Views:
Transcription
1 Last Time: Object Design Comp435 Object-Oriented Design Week 7 Computer Science PSU HBG The main idea RDD: Responsibility-Driven Design Identify responsibilities Assign them to classes and objects Responsibilities are an abstraction Concretely, implemented with classes, their methods and in terms of how they collaborate with other objects. 1 2 Last Time: Responsibilities Responsibilities for doing create an object perform calculations initiate operations on other objects control and coordinate activities Responsibility for knowing about private encapsulated data about related objects Last Time: The 9 GRASP Patterns The guiding principles to assign responsibilities Information Expert Creator Low Coupling Pure Fabrication Indirection Protected Variations 3 4 Last Time: Creator What object creates an object X? Doing responsibility Choose an object C, such that: C contains X C records X C closely uses X C has the initializing data for X The more, the better Last Time: Information Expert Most basic responsibility assignment principle Assign the responsibility to an object that has the information needed to fulfill it That which has the information does the work 5 6 1
2 Low Coupling Low Coupling Coupling How one class is connected to other classes How one class has knowledge of other classes How one class relies on other classes Assign responsibilities so that coupling remains low Consider classes Payment, Register, Sale We need to create a Payment instance and associate it with Sale Which class creates the payment object? Register Payment Sale 7 8 Low Coupling Solution 1 makepayment(x) 1: create(x) 2: addpayment(p) p:payment Solution 2 makepayment(x) 1: makepayment(x) 1.1: create(x) Which is better? :Payment 9 Low Coupling s of Coupling Class A has an attribute of class B An instance of A calls a method in class B or an instance of B A has a method that references instances of B, e.g., a local variable A is a direct or indirect subclass of B A implements an interface B 10 Summary Low Coupling Low coupling is a general principle to keep in mind during design Inherently generic classes should have especially low coupling Is extremely low coupling a good thing? Some coupling is necessary Avoid unnecessary coupling Cohesion How strongly related and focused the responsibilities of a class are A low cohesion class Does unrelated things Does too many things Why not have low cohesion in a class?
3 Who creates Payment objects? Option 1 makepayment(x) 1: create(x) p:payment 2: addpayment(p) Register Payment Sale Option 2 makepayment(x) 1: makepayment(x) 1.1: create(x) 13 Which is better? :Payment 14 Problem with Low Cohesion A class is solely responsible for many things in very different functional areas Example A class RDB-RPC-Interface responsible for Relational Databases (RDB) Remote Procedure Calls (RPC) Very different functional areas. May need to split in 2 classes. Problem with Low Cohesion A class has sole responsibility for a complex task in one functional area Example: A class RDBInterface Responsible for interacting with Relational Databases Methods are related, but too many of them May need to split into a family of lightweight classes A class has moderate responsibilities In one functional area Collaborates with other classes to fulfill tasks A class RDBInterface, but only partially responsible for database interactions Summary A class with high cohesion Relatively small number of operations with highly related functionality Not too much work collaborates with other classes to share work
4 Benefits Ease of understanding Maintenance and enhancement are simplified Often results in low coupling Cohesive classes are easier to reuse Handling of System Events Who is responsible for handling System events? First object responsible for a system operation In the SSD, a conceptual class System handles system events :Cashier makenewsale() :System This does not mean that a System software class is created during design Assigned to one or more controller classes Common candidates: Façade A class that represents the overall system, device or subsystem Ex: Register Use Case : A class that represents the use case or session Often named as ProcessSaleHandler ProcessSaleCoordinator ProcessSaleSession System events in the POS system makenewsale(), enteritem(), endsale(), makepayment() In Layered model UI layer generates the event Window :??? enteritem(itemid, qty) UI Layer Domain Layer 23 Option 1 Represent the entire system or device Ex: Register Option 2 A handler for all events in a particular use case Ex: ProcessSaleHandler UI Layer Domain Layer Window enteritem( ) Window enteritem( ) :ProcessSaleHandler 24 4
5 Observations One controller for all events in one use case Keep info about the state of the use case Discover out-of-order events Ex: makepayment occurs before endsale Common Problem s are given too much responsibility Should delegate to other objects Should mostly coordinate/control Façade Abstraction of the overall physical unit Suitable when There are not too many events UI cannot redirect events to other objects Possible problem Bloated controllers Use-case A different controller for each use case An artificial construct to suppoert the system Not a domain concept Ex: UseCase: ProcessSale ProcessSaleHandler Use when there are too many system events Separates their handling into manageable separate classes Provides basis for knowing the state of the current use case scenario UI Objects / UI Layer should not be responsible for handling system events Window 1: enteritem() 1: makelineitem() 1.1: makelineitem() Client/Server Applications Client side UI + s UI sends request to controller forwards the request to a remote server Server side Often there are use case controllers How to handle alternatives based on type Conditional variation: hard to maintain Use polymorphic operators How to create pluggable components Replace a component without affecting the system Based on polymorphism, the abstraction can take many forms Many possible subclasses Many possible implementations of an interface Modern OO languages support all these mechanisms
6 Class Hierarchies How do we ensure correctness of class hierarchies? Superclass-subclass relationships Domain model Relationships between concepts An instance of X is also an instance of Y Design model Relationships between software entities Implemented through inheritance Inheritance in C++ class B : public A { Multiple inheritance supported Every member of A is inherited by B Instance field f defined in A Every object of class B has a field f; If a method m is defined in A, B inherits it B may declare new members B may override inherited members Liskov Substitution Principle (LSP) Key principle: A subclass must be substitutable for its superclasses Example class B : public A {... A function or method foo(a* a) foo behaves correctly when the parameter is an instance of A foo should behave correctly when the parameter is an instance of B Without foo knowing about the existence of B 33 Liskov Substitution Principle (LSP) Protection against variability of subclasses If foo was written correctly with respect to A, it should be possible to substitute a B object for the A object without affecting correctness LSP is stronger than LSP If we add a new subclass of A, foo will still be correct If we add a new subclass of A, we don t need to recompile foo (language mechanism) 34 Classic Example class Rectangle { protected: double h,w; Point topleft; public: double setheight (double x) { h=x; double setwidth (double x) { w=x; double getheight () { return h; double getwidth () { return w; double area() { return h*w; Suppose we have written a lot of code that uses Rectangle 35 Adding a Square At some point we decide that we need a square A square is a kind of Rectangle class Square : public Rectangle { With polymorphism, we don t have to recompile existing code E.g., void m(rectangle x) { does not have to be recompiled But there are problems 36 6
7 Problems Square doesn t really need both w and h Wasted memory (but relatively minor thing) Square inherits setheight and setwidth Incorrect behavior One possible solution Guards in client code Ex: rectangle r; r.setheight(5); if (r instanceof Square) r.setwidth(5); Makes the client code very fragile; bad idea!!! Another solution Override setheight and setwidth in Square class Square : public Rectangle { public void setheight(double x) { h=x; w=x; public void setwidth(double x) { h=x; w=x; More Problems void foo (Rectangle r) { r.setheight(5); r.setwidth(4); assert (r.area() == 20); Valid code, with only Rectangle objects But now it may break. The programmer of foo is justified in writing this code There is something wrong with square 39 LSP If foo was written correctly wrt to a superclass, it should be possible to substitute a subclass instance for the superclass instance and still be correct Square violates LSP Postcondition for Rectangle.setHeight: h == x and w == w old Postcondition for Square.setHeight: h == x and w == x The subclass postcondition does not imply the superclass postcondition 40 Ensuring LSP One way to ensure that LSP is not violated Considering preconditions and postconditions Whenever a subclass overrides a method of a superclass The precondition for the superclass should imply the precondition for the subclass The postcondition for the subclass should imply the postcondition for the superclass LSP is about behavior If foo ever gets a Square object and calls setheight on it, the behavior does not conform to the behavior of setheight in Rectangle Due to postconditions Inheritance should be more than just is-akind-of relationship: it should guarantee conformance of behavior Often used term: behavioral subtyping
8 The role of LSP Should be used as a warning flag It may be OK to violate it But the violation should be examined carefully Depends on the client of the hierarchy If we have a program in which height and width are never changed, it may be OK to have a Square as a subclass of Rectangle 43 Another Example class Polygon { public: void move (int x,int y) { void addvertex (Point p) { int numvert() {return vertices.size(); private: Set vertices; class Triangle :: public Polygon { public void addvertex(point p) { Needs to override addvertex to do nothing Postcondition for addvertex In Polygon: vertices = 1 + vertices old In Triangle: vertices = vertices old = 3 44 Possible Solution LSP is violated for Triangle Also for subclasses Rectangle, Hexagon, etc. One possible solution Create two subclasses of Polygon Subclass FixedSidedPolygon» with its own subclasses Triangle, Rectangle, etc. Subclass VariableSidedPolygon» in which addvertex is defined» addvertex is not defined in Polygon Indirection Another popular mechanism for protection from variations Where to assign a responsibility How to avoid direct coupling between 2 objects How to decouple object for low coupling Simple idea: use an intermediary Add a level of indirection Assign responsibility to an intermediate object Indirection Pure Fabrication : Tax calculator adapters :TaxMasterAdapter t = gettotal taxes = gettaxes (s) xxx «actor» :TaxMasterSystem Assigning responsibility only to domain objects may results in poor cohesion high coupling low reuse potential Solution: use an artificially made-up class To assign highly cohesive set of responsibilities
9 Pure Fabrication Want to save Sale instance in database Information Expert Assign the responsibility to Sale Problem Sale becomes incohesive Sale needs to be coupled with the database Sale becomes hard to reuse... Solution Use an artificial class solely responsible for saving Protected Variations Protecting one part of the program from changes in another part Protected variations Open-closed principle Common mechanisms Encapsulation Abstraction Indirection Protected Variations More ambitious mechanisms At run time, clients use a lookup service to find a server (protects against location and implementation changes) External rules are read and executed by an interpreter (flexibility wrt rule changes) 51 9
GRASP: Patterns for. chapter18
GRASP: Patterns for assigning responsibility chapter18 1 Chapter Objectives Learn about design patterns Learn how to apply five GRASP patterns 2 Building Collaboration diagrams System Design: how the system
More informationInformation Expert (or Expert)
Page 2 Page 3 Pattern or Principle? Information Expert (or Expert) Class Responsibility Sale Knows Sale total SalesLineItem Knows line item total ProductDescription Knows product price The GRASP patterns
More informationADVANCED SOFTWARE DESIGN LECTURE 7 GRASP
ADVANCED SOFTWARE DESIGN LECTURE 7 GRASP Dave Clarke 1 TODAY S LECTURE We will discuss 7 of the GRASP design patterns cohesion and coupling were covered earlier. These provide principles for evaluating
More informationADVANCED SOFTWARE DESIGN LECTURE 4 GRASP. Dave Clarke
ADVANCED SOFTWARE DESIGN LECTURE 4 GRASP Dave Clarke TODAY S LECTURE We will discuss and apply the GRASP design patterns. These provide principles for evaluating and improving designs. friends User Name??
More informationResponsibilities. Using several specific design principles to guide OO design decisions.
Designing Objects with Responsibilities Using several specific design principles to guide OO design decisions. Challenge Old-school advice on OOD After identifying i your requirements and creating a domain
More informationCOMP 6471 Software Design Methodologies
COMP 6471 Software Design Methodologies Fall 2011 Dr Greg Butler http://www.cs.concordia.ca/~gregb/home/comp6471-fall2011.html Page 2 Sample UP Artifact Relationships Domain Model Context Business Modeling
More informationGRASP 2. CSC 440: Software Engineering Slide #1
GRASP 2 CSC 440: Software Engineering Slide #1 GRASP Patterns General Responsibility Assignment Software Patterns Describe fundamental principles of object design and responsibility assignment. Five GRASP
More informationGRASP Design Patterns A.A. 2018/2019
GRASP Design Patterns A.A. 2018/2019 Objectives Introducing design patterns Introduzione ai design pattern Designing objects and responsibilities GRASP design patterns A long corridor A passage room Does
More informationAssigning Responsibilities by Larman
Assigning Responsibilities by Larman Core design activity: The identification of objects and responsibilities and providing a solution in terms of an interaction diagram this is the creative part where
More information2 GRASP Patterns and basic OO Design. Roel Wuyts OASS
2 GRASP Patterns and basic OO Design Roel Wuyts OASS1 2009-2010 Patterns 2 Bit of history... Christoffer Alexander The Timeless Way of Building, Christoffer Alexander, Oxford University Press, 1979, ISBN
More informationObject Analysis & Design in the textbook. Introduction to GRASP: Assigning Responsibilities to Objects. Responsibility-Driven Design
Object Analysis & Design in the textbook Chapter 2 Object Oriented Design Process Introduction to GRASP: Assigning Responsibilities to Objects CS 4354 Summer II 2016 Jill Seaman Much of the material in
More informationAssigning Responsibilities (Patterns of Responsibility Assignment Principles: GRASP)
Subsystem design basics Assigning Responsibilities (Patterns of Responsibility Assignment Principles: GRASP) Dept. of Computer Science Baylor University Focus on modeling how subsystems accomplish goals
More informationPrinciples of Software Construction: Objects, Design, and Concurrency. Assigning Responsibilities to Objects. toad. Jonathan Aldrich Charlie Garrod
Principles of Software Construction: Objects, Design, and Concurrency Assigning Responsibilities to Objects toad Fall 2014 Jonathan Aldrich Charlie Garrod School of Computer Science Key concepts from Thursday
More informationObject-Oriented Design
Object-Oriented Design Department of Computer Engineering Lecture 12: Object-Oriented Principles Sharif University of Technology 1 Open Closed Principle (OCP) Classes should be open for extension but closed
More informationFour More GRASP Principles CSSE 574: Session 5, Part 2
Four More GRASP Principles CSSE 574: Session 5, Part 2 Steve Chenoweth Phone: Office (812) 877-8974 Cell (937) 657-3885 Email: chenowet@rose-hulman.edu GRASP II And Furthermore Polymorphism Indirection
More informationOutline. Subtype Polymorphism, Subtyping vs. Subclassing, Liskov Substitution Principle. Benefits of Subtype Polymorphism. Subtype Polymorphism
Subtype, Subtyping vs. Subclassing, Liskov Substitution Principle Outline Subtype polymorphism Subtyping vs. subclassing Liskov Substitution Principle (LSP) Function subtyping Java subtyping Composition:
More informationn HW5 out, due Tuesday October 30 th n Part 1: Questions on material we ll cover today n Part 2: BFS using your graph from HW4
Subtype, Subtyping vs. Subclassing, Liskov Substitution Principle Announcements n HW5 out, due Tuesday October 30 th n Part 1: Questions on material we ll cover today n Part 2: BFS using your graph from
More informationLecture: Modular Design
Software Engineering Lecture: Modular Design Thomas Fritz Many thanks to Philippe Beaudoin, Gail Murphy, David Shepherd, Neil Ernst and Meghan Allen Reading! For next lecture: (all required) Composite
More informationOn to Object-oriented Design
Dr. Michael Eichberg Software Technology Group Department of Computer Science Technische Universität Darmstadt Introduction to Software Engineering On to Object-oriented Design Object-oriented Design 2
More informationReferences: Applying UML and patterns Craig Larman
References: Applying UML and patterns Craig Larman 1 2 What are patterns? Principles and solutions codified in a structured format describing a problem and a solution A named problem/solution pair that
More informationPrinciples of Object-Oriented Design
Principles of Object-Oriented Design 1 The Object-Oriented... Hype What are object-oriented (OO) methods? OO methods provide a set of techniques for analysing, decomposing, and modularising software system
More informationObject-Oriented Design
Object-Oriented Design Lecturer: Raman Ramsin Lecture 15: Object-Oriented Principles 1 Open Closed Principle (OCP) Classes should be open for extension but closed for modification. OCP states that we should
More information17. GRASP: Designing Objects with Responsibilities
17. GRASP: Designing Objects with Responsibilities Objectives Learn to apply five of the GRASP principles or patterns for OOD. Dr. Ziad Kobti School of Computer Science University of Windsor Understanding
More informationObject Oriented Software Design - I
Object Oriented Software Design - I Object Oriented Design Principles Giuseppe Lipari http://retis.sssup.it/~lipari Scuola Superiore Sant Anna Pisa October 28, 2011 G. Lipari (Scuola Superiore Sant Anna)
More informationObject-Oriented Design II
Object-Oriented Design II SWEN-261 Introduction to Software Engineering Department of Software Engineering Rochester Institute of Technology Controller Pure fabrication Open/close Polymorphism Liskov substitution
More informationDesign Principles: Part 2
Liskov Substitution Principle (LSP) Dependency-Inversion Principle (DIP) Interface-Segregation Principle (ISP) Design Principles: Part 2 ENGI 5895: Software Design Andrew Vardy Faculty of Engineering &
More informationEliminate enterprise software design instability - protect variations! Nickolay Kofanov
Eliminate enterprise software design instability - protect variations! Nickolay Kofanov Owning a hammer doesn't make one an architect. Responsibility-Driven-Design The way of thinking about the design
More informationSoftware Engineering CSC40232: SOFTWARE ENGINEERING. Guest Lecturer: Jin Guo SOLID Principles sarec.nd.edu/courses/se2017
CSC40232: SOFTWARE ENGINEERING Guest Lecturer: Jin Guo SOLID Principles sarec.nd.edu/courses/se2017 Department of Computer Science and Engineering http://www.kirkk.com/modularity/2009/12/solid-principles-of-class-design/
More informationDesign Principles: Part 2
Liskov Substitution Principle (LSP) Dependency-Inversion Principle (DIP) Interface-Segregation Principle (ISP) Design Principles: Part 2 ENGI 5895: Software Design Andrew Vardy Faculty of Engineering &
More informationOutline. Design Principles: Part 2. e.g. Rectangles and Squares. The Liskov Substitution Principle (LSP) ENGI 5895: Software Design.
Liskov Substitution Principle (LSP) Dependency-Inversion Principle (DIP) Interface-Segregation Principle (ISP) Liskov Substitution Principle (LSP) Dependency-Inversion Principle (DIP) Interface-Segregation
More informationIntroduction to Software Engineering (2+1 SWS) Winter Term 2009 / 2010 Dr. Michael Eichberg Vertretungsprofessur Software Engineering Department of
Introduction to Software Engineering (2+1 SWS) Winter Term 2009 / 2010 Dr. Michael Eichberg Vertretungsprofessur Software Engineering Department of Computer Science Technische Universität Darmstadt Dr.
More informationTest Code Patterns. How to design your test code
Test Code Patterns How to design your test code Testing and Inheritance n Should you retest inherited methods? n Can you reuse superclass tests for inherited and overridden methods? n To what extent should
More informationTesting and Inheritance. Test Code Patterns. Inheritance-related bugs. Inheritance. Testing of Inheritance. Inheritance-related bugs
Test Code Patterns How to design your test code Testing and Inheritance n Should you retest inherited methods? n Can you reuse superclass tests for inherited and overridden methods? n To what extent should
More informationLiskov Substitution Principle
Liskov Substitution Principle Produced by: Eamonn de Leastar (edeleastar@wit.ie) Dr. Siobhán Drohan (sdrohan@wit.ie) Department of Computing and Mathematics http://www.wit.ie/ SOLID Class Design Principles
More information11/2/09. Code Critique. What goal are we designing to? What is the typical fix for code smells? Refactoring Liskov Substitution Principle
Code Critique Identifying smells Refactoring Liskov Substitution Principle What goal are we designing to? What is the typical fix for code smells? What is a limitation of those fixes? How do we address
More informationIntroduction to Object-Oriented Programming
Introduction to Object-Oriented Programming Inheritance, Part 2 of 2 Christopher Simpkins chris.simpkins@gatech.edu CS 1331 (Georgia Tech) Inheritance, Part 2 of 2 1 / 14 Access Modifiers Modifier Class
More informationS.O.L.I.D: Software Engineering Principles
DCC / ICEx / UFMG S.O.L.I.D: Software Engineering Principles Eduardo Figueiredo http://www.dcc.ufmg.br/~figueiredo S.O.L.I.D Principles These principles intend to create systems that are easier to maintain
More informationFrom Design Patterns: Elements of Reusable Object Oriented Software. Read the sections corresponding to patterns covered in the following slides.
From Design Patterns: Elements of Reusable Object Oriented Software Read the sections corresponding to patterns covered in the following slides. DESIGN PRINCIPLES Modularity Cohesion Coupling Separation
More informationPrinciples of Software Construction: Objects, Design and Concurrency. Object-Oriented Design: Assigning Responsibilities.
Principles of Software Construction: Objects, Design and Concurrency 15-214 toad Object-Oriented Design: Assigning Responsibilities Christian Kästner Charlie Garrod School of Computer Science With slides
More information2009 Shawn A. Bohner. Shawn Bohner Office: Moench Room F212 Phone: (812)
2009 Shawn A. Bohner Shawn Bohner Office: Moench Room F212 Phone: (812) 877-8685 Email: bohner@rose-hulman.edu GRASP II And Furthermore Polymorphism Indirection Pure Fabrication Protected Variations 2
More informationObject-Oriented Design II - GRASP
Object-Oriented Design II - GRASP SWEN-610 Foundations of Software Engineering Department of Software Engineering Rochester Institute of Technology Controller Creator Indirection Information expert High
More informationSoftware Engineering
Software Engineering CSC 331/631 - Spring 2018 Object-Oriented Design Principles Paul Pauca April 10 Design Principles DP1. Identify aspects of the application that vary and separate them from what stays
More informationCTIS 359 Principles of Software Engineering SOFTWARE DESIGN OO(A)D
CTIS 359 Principles of Software Engineering SOFTWARE DESIGN OO(A)D Today s Objectives To explain the basic concepts of OO(A)D To describe some best practices regarding to OO(A)D What is NOT UML? The UML
More informationProgramming in the large
Inheritance 1 / 28 Programming in the large Software is complex. Three ways we deal with complexity: Abstraction - boiling a concept down to its essential elements, ignoring irrelevant details Decomposition
More informationIntroduction to Software Engineering (2+1 SWS) Winter Term 2009 / 2010 Dr. Michael Eichberg Vertretungsprofessur Software Engineering Department of
Introduction to Software Engineering (2+1 SWS) Winter Term 2009 / 2010 Dr. Michael Eichberg Vertretungsprofessur Software Engineering Department of Computer Science Technische Universität Darmstadt What
More informationGRASP ing at the First 5 Patterns Principles CSSE 574: Session 3, Part 4
GRASP ing at the First 5 Patterns Principles CSSE 574: Session 3, Part 4 Steve Chenoweth Phone: Office (812) 877-8974 Cell (937) 657-3885 Email: chenowet@rose-hulman.edu GRASP General Responsibility Assignment
More informationTecniche di Progettazione: Design Patterns
Tecniche di Progettazione: Design Patterns Design principles 1 Plan of the lecture Your state of the art SOLID Grasp (to be continued next week) 2 Short summary of what you must know Few things on design
More informationObject-Oriented Design I - SOLID
Object-Oriented Design I - SOLID SWEN-261 Introduction to Software Engineering Department of Software Engineering Rochester Institute of Technology Single responsibility Open/close Liskov substitution
More informationObject-Oriented Concepts and Design Principles
Object-Oriented Concepts and Design Principles Signature Specifying an object operation or method involves declaring its name, the objects it takes as parameters and its return value. Known as an operation
More informationPatterns and Testing
and Lecture # 7 Department of Computer Science and Technology University of Bedfordshire Written by David Goodwin, based on the lectures of Marc Conrad and Dayou Li and on the book Applying UML and (3
More informationPrinciples of OO Design
Principles of OO Design Ing. Libor Buš PhD. Department of Software Engineering Faculty of Information Technology Czech Technical University in Prague MI-DPO WS 2010/11, Lecture 1 Evropský sociální fond
More informationADVANCED SOFTWARE DESIGN LECTURE 4 SOFTWARE ARCHITECTURE
ADVANCED SOFTWARE DESIGN LECTURE 4 SOFTWARE ARCHITECTURE Dave Clarke 1 THIS LECTURE At the end of this lecture you will know notations for expressing software architecture the design principles of cohesion
More informationOO Design2. Design Artifacts
OO Design2 POS example - revisited LAR Ch 8 has entire POS design explained READ THIS CHAPTER and ASK Q s in class Design class diagrams Kinds of visibility of objects to one another Navigability of associations
More informationCPSC 410? Advanced Software Engineering Mid-term Examination (Term I ) SOLUTION Instructor: Gail Murphy
CPSC 410? Advanced Software Engineering Mid-term Examination (Term I 2001-2002) SOLUTION Instructor: Gail Murphy Do NOT start until you are informed you can start! This examination has 7 questions. The
More information18.1 Definitions and General OO Principles
Chapter 18: Design Patterns Design patterns are elegant, adaptable, and reusable solutions to everyday software development problems. Each pattern includes a description of a commonly occuring type of
More informationCSC207 Week 3. Larry Zhang
CSC207 Week 3 Larry Zhang 1 Announcements Readings will be posted before the lecture Lab 1 marks available in your repo 1 point for creating the correct project. 1 point for creating the correct classes.
More informationOODP Session 5a. Web Page: Visiting Hours: Tuesday 17:00 to 19:00
OODP Session 5a Next week: Reading week Session times PT group 1 Monday 18:00 21:00 room: Malet 403 PT group 2 Thursday 18:00 21:00 room: Malet 407 FT Tuesday 13:30 17:00 room: Malet 404 Email: oded@dcs.bbk.ac.uk
More informationIntro to: Design Principles
Intro to: Design Principles Pragmatic Programmer: Eliminate Effects Between Unrelated Things design components that are: self-contained, independent, and have a single, well-defined purpose Software Design
More informationInheritance and object compatibility
Inheritance and object compatibility Object type compatibility An instance of a subclass can be used instead of an instance of the superclass, but not the other way around Examples: reference/pointer can
More informationSoftware Engineering /48
Software Engineering 1 /48 Topics 1. The Compilation Process and You 2. Polymorphism and Composition 3. Small Functions 4. Comments 2 /48 The Compilation Process and You 3 / 48 1. Intro - How do you turn
More informationCOURSE 2 DESIGN PATTERNS
COURSE 2 DESIGN PATTERNS CONTENT Fundamental principles of OOP Encapsulation Inheritance Abstractisation Polymorphism [Exception Handling] Fundamental Patterns Inheritance Delegation Interface Abstract
More informationSoftware Engineering
Software Engineering 5. Software Design und Design Prinzipien Jonathan Brachthäuser Software Engineering Einordnung Problem Continuous Delivery & Feedback Lösung Anforderungsermittlung - (Nicht- )funktionale
More informationGoal: build an object-oriented model of the realworld system (or imaginary world) Slicing the soup: OOA vs. OOD
Domain analysis Goal: build an object-oriented model of the realworld system (or imaginary world) Slicing the soup: OOA vs. OOD OOA concerned with what, not how OOA activities focus on the domain layer
More informationSOLID Principles. Equuleus Technologies. Optional Subheading October 19, 2016
SOLID Principles Optional Subheading October 19, 2016 Why SOLID Principles? The traits of well designed software are as follows Maintainability - The ease with which a software system or component can
More informationGRASP: MORE PATTERNS FOR
Chapter 22 GRASP: MORE PATTERNS FOR ASSIGNING RESPONSIBILITIES Luck is the residue of design. Branch Rickey Objectives Learn to apply the remaining GRASP patterns. Introduction Previously, we explored
More informationExpanding Our Horizons. CSCI 4448/5448: Object-Oriented Analysis & Design Lecture 9 09/25/2011
Expanding Our Horizons CSCI 4448/5448: Object-Oriented Analysis & Design Lecture 9 09/25/2011 1 Goals of the Lecture Cover the material in Chapter 8 of our textbook New perspective on objects and encapsulation
More informationCS 520 Theory and Practice of Software Engineering Fall 2018
Today CS 520 Theory and Practice of Software Engineering Fall 2018 Object Oriented (OO) Design Principles September 13, 2018 Code review and (re)design of an MVC application (and encapsulation) Polymorphism
More informationOriginality is Overrated: OO Design Principles
Originality is Overrated: OO Design Principles Kenneth M. Anderson University of Colorado, Boulder CSCI 4448/6448 Lecture 13 10/09/2007 University of Colorado, 2007 1 Lecture Goals Review material from
More informationOO Design Principles
OO Design Principles Software Architecture VO (706.706) Roman Kern Institute for Interactive Systems and Data Science, TU Graz 2018-10-10 Roman Kern (ISDS, TU Graz) OO Design Principles 2018-10-10 1 /
More informationCOMP 6471 Software Design Methodologies
COMP 647 Software Design Methodologies Fall 20 Dr Greg Butler http://www.cs.concordia.ca/~gregb/home/comp647-fall20.html Course Introduction Course People Course Components What the course is What the
More informationChapter 6: Inheritance
Chapter 6: Inheritance EECS 1030 moodle.yorku.ca State of an object final int WIDTH = 3; final int HEIGTH = 4; final int WEIGHT = 80; GoldenRectangle rectangle = new GoldenRectangle(WIDTH, HEIGHT, WEIGHT);
More informationConstantinos Constantinides Computer Science and Software Engineering Concordia University Montreal, Canada
1 Disclaimer: These slides are based on the 2 nd edition of Applying UML and Patterns; An introduction to OOAD and the Unified process by Craig Larman (2002). I take responsibility for any errors. Constantinos
More information17.11 Bean Rules persistent
17.10 Java Beans Java beans are a framework for creating components in Java. AWT and Swing packages are built within this framework Made to fit in with graphic development environments such as Jbuilder
More informationObject-oriented design principles
Object-oriented design principles Objektumorientált szoftvertervezés Object-oriented software design Dr. Balázs Simon BME, IIT Outline OO concepts Single Responsibility Principle (SRP) Open/Closed Principle
More informationThe Liskov Substitution Principle
Agile Design Principles: The Liskov Substitution Principle Based on Chapter 10 of Robert C. Martin, Agile Software Development: Principles, Patterns, and Practices, Prentice Hall, 2003 and on Barbara Liskov
More informationOO Class Design Principles
3.3 Class Design Principles Single Responsibility Principle (SRP) Open/Closed Principle (OCP) Liskov Substitution Principle (LSP) a.k.a. Design by Contract Dependency Inversion Principle (DIP) Interface
More informationSummary of the course lectures
Summary of the course lectures 1 Components and Interfaces Components: Compile-time: Packages, Classes, Methods, Run-time: Objects, Invocations, Interfaces: What the client needs to know: Syntactic and
More information11/4/15. Review. Objec&ves. Refactoring for Readability. Review. Liskov Subs&tu&on Principle (LSP) LISKOV SUBSTITUTION PRINCIPLE
Objec&ves Liskov Subs&tu&on Principle Good enough design Refactoring for Extensibility Review What are some metrics of code design? Ø How can we use the metric? Ø What is the intui&on behind the metric?
More informationLogical Architecture & Design Preliminaries
Logical Architecture & Design Preliminaries CSSE 574: Week 2, Part 4 Steve Chenoweth Phone: Office (812) 877-8974 Cell (937) 657-3885 Email: chenowet@rose-hulman.edu From Requirements to Architecture Customer
More information6.170 Recitation #5: Subtypes and Inheritance
6.170 Recitation #5: Subtypes and Inheritance What is true subtyping? True Subtyping is not exactly the same as Inheritance. As seen in an earlier lecture, class A is a true subtype of class B if and only
More informationCS 520 Theory and Practice of Software Engineering Fall 2017
CS 520 Theory and Practice of Software Engineering Fall 2017 OO design principles September 14, 2017 Today Code review and (re)design of an MVC application OO design principles Information hiding (and
More informationIndex. Index. More information. block statements 66 y 107 Boolean 107 break 55, 68 built-in types 107
A abbreviations 17 abstract class 105 abstract data types 105 abstract method 105 abstract types 105 abstraction 92, 105 access level 37 package 114 private 115 protected 115 public 115 accessors 24, 105
More informationCSC207H: Software Design SOLID. CSC207 Winter 2018
SOLID CSC207 Winter 2018 1 SOLID Principles of Object-Oriented Design How do we make decisions about what is better and what is worse design? Principles to aim for instead of rules. e.g. there is no maximum
More informationRDD and Strategy Pa.ern
RDD and Strategy Pa.ern CSCI 3132 Summer 2011 1 OO So1ware Design The tradi7onal view of objects is that they are data with methods. Smart Data. But, it is be.er to think of them as en##es that have responsibili#es.
More informationConception Orientée Objets. Programmation SOLID
Conception Orientée Objets Programmation SOLID Frédéric Mallet http://deptinfo.unice.fr/~fmallet/ F. Mallet SOLID 1 Objectives Introduce some principles to guide the design Single responsibility Open Closed
More informationAbstraction. Design fundamentals in OO Systems. Fundamental Software Development Principles
Abstraction Design fundamentals in OO Systems Tool for abstraction: object Object structure: properties and values for those properties operations to query and update those properties We refer to the collection
More informationObject Relationships
Object Relationships Objects can work together in three different types of relationships: Uses: An object can use another to do some work (association). Composition: A complex object may be composed of
More informationCSSE 374: GRASP ing at the First Five Patterns Principles. Shawn Bohner Office: Moench Room F212 Phone: (812)
CSSE 374: GRASP ing at the First Five Patterns Principles Shawn Bohner Office: Moench Room F22 Phone: (82) 877-8685 Email: bohner@rose-hulman.edu Learning Outcomes: Patterns, Tradeoffs Identify criteria
More informationOn to Object-oriented Design
Dr. Michael Eichberg Software Engineering Department of Computer Science Technische Universität Darmstadt Software Engineering On to Object-oriented Design Object-oriented Design 2 A popular way of thinking
More informationSoftware Design Patterns. Background 1. Background 2. Jonathan I. Maletic, Ph.D.
Software Design Patterns Jonathan I. Maletic, Ph.D. Department of Computer Science Kent State University J. Maletic 1 Background 1 Search for recurring successful designs emergent designs from practice
More informationVEL TECH HIGH TECH Dr. RANGARAJAN Dr. SAKUNTHALA ENGINEERING COLLEGE UNIT 1 UML DIAGRAMS
UNIT 1 UML DIAGRAMS Introduction to OOAD Unified Process - UML diagrams Use Case Class Diagrams Interaction Diagrams State Diagrams Activity Diagrams Package, component and Deployment Diagrams. INTRODUCTION
More informationLecture 11 Subtypes and Subclasses
CSE 331 Software Design and Implementation Lecture 11 Subtypes and Subclasses The Liskov Substitution Principle Let P(x) be a property provable about objects x of type T. Then P(y) should be true for objects
More informationCSE 331 Software Design and Implementation. Lecture 12 Subtypes and Subclasses
CSE 331 Software Design and Implementation Lecture 12 Subtypes and Subclasses Zach Tatlock / Winter 2016 The Liskov Substitution Principle Let P(x) be a property provable about objects x of type T. Then
More informationSoftware Engineering Design & Construction
Winter Semester 16/17 Software Engineering Design & Construction Dr. Michael Eichberg Fachgebiet Softwaretechnik Technische Universität Darmstadt Liskov Substitution Principle 2 Liskov Substitution Principle
More informationTesting Object-Oriented Software. 22 November 2017
Testing Object-Oriented Software 22 November 2017 Testing Object-Oriented Software 2 Problems in object-oriented testing [Binder] Each level in the class hierarchy creates a new context for inherited features:
More informationChapter 5 Object-Oriented Programming
Chapter 5 Object-Oriented Programming Develop code that implements tight encapsulation, loose coupling, and high cohesion Develop code that demonstrates the use of polymorphism Develop code that declares
More informationMapping Designs to Code
Mapping Designs to Code Creating Class Definitions from DCDs public class SalesLineItem private int quantity; private ProductDescription description ; public SalesLineItem(ProductDescription desc, int
More informationDesign patterns. Jef De Smedt Beta VZW
Design patterns Jef De Smedt Beta VZW Who Beta VZW www.betavzw.org Association founded in 1993 Computer training for the unemployed Computer training for employees (Cevora/Cefora) 9:00-12:30 13:00-16:00
More informationJAVA PROGRAMMING LAB. ABSTRACT In this Lab you will learn how to describe objects and classes and how to define classes and create objects
Islamic University of Gaza Faculty of Engineering Computer Engineering Dept Computer Programming Lab (ECOM 2114) ABSTRACT In this Lab you will learn how to describe objects and classes and how to define
More informationRelationships amongst Objects
Relationships amongst Objects By Rick Mercer with help from Object-Oriented Design Heuristics Arthur Riel Addison-Wesley, 1996, ISBN 0-201-6338-X 8-1 Outline Consider six relationships between objects
More information