CSE564 Lecture 11

Transcript

1. jgs CSE 564 Software Design Lecture 11: Design Patterns: Builder

   and Factory Dr. Javier Gonzalez-Sanchez javiergs@asu.edu javiergs.engineering.asu.edu | javiergs.com PERALTA 230U Office Hours: By appointment

2. jgs Previously

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   GoF Patterns

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   Test Yourselves CSE 110 Academic Status Report Grade Roster Class Roster

5. jgs Builder Wrapper of an object When an object cannot

   be produced in one step

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   GoF Patterns

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   Builder

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   // For creating complex objects // Delegate to several builders public class Client { public static void main( string[] args ) { Director director = new Director( ); StudentBuilder sBuilder = new StudentBuilder(); InstructorBuilder iBuilder = new InstructorBuilder(); director.constructStudent( sBuilder ); Student s = sBuilder.getResult(); s.show(); director.constructInstructor( iBiulder ); Instructor i = iBuilder.GetResult(); i.Show(); } } Builder pattern

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   Builder pattern class Director { public void constructStudent( Builder builder ) { builder.setSalary(“10”); builder.setAccess(“LIMITED”); builder.setHours(“20”); builder.setComputer(“no”); } public void constructInstructor( Builder builder ) { builder.setSalary(“50”); builder.setAccess(“FULL”); builder.setHours(“40”); builder.setComputer(“yes”); } }

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    Builder pattern interface Builder { void setSalary (String salary); void setAccess (String access); void setHours (String hours); void setComputer(String computer); } class StudentBuilder extends Builder { private int salary; private String access; private int hours); private Computer c; // setters for all variables public void setSalary (int salary) { this.salary = Integer.parseInt(salary)); } public void setAccess (String access) {this.access = access;} public void setHours (String hours) {this.hours = Integer.parseInt(hours)); } public void setComputer(String computer) {c = computer.equals(“yes”)?new Computer():null;} public Student getResult() { // you can validate here that all data exist return new Student (salary, access, hours, computer); } }

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    Builder pattern interface Builder { void setSalary (String salary); void setAccess (String access); void setHours (String hours); void setComputer(String computer); } class InstructorBuilder extends Builder { private int salary; private String access; private int hours; private Computer c; // setters for all variables public void setSalary (int salary) { this.salary = Integer.parseInt(salary)); } public void setAccess (String access) {this.access = access;} public void setHours (String hours) {this.hours = Integer.parseInt(hours)); } public void setComputer(String computer) {c = new Computer();} public Student getResult() { // you can validate here that all data exist return new Instructor (salary, access, hours, computer); } }

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    Builder pattern class Student { private int salary; private String access; private int hours; private Computer c; // common simple trivial getters // common simple trivial setters // common simple trivial constructor // what about making the constructor private ? } class Instructor { private int salary; private String access; private int hours; private Computer c; // common simple trivial getters // common simple trivial setters // common simple trivial constructor // what about making the constructor private ? }

13. jgs Factory Wrapper of a constructor One entire object to

    be built in a single method call

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    GoF Patterns

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    Abstract Factory

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    Products public interface Shape { void draw(); } public class RoundedRectangle implements Shape { public void draw() { System.out.println("Inside RoundedRectangle/draw() method."); } } public class RoundedSquare implements Shape { public void draw() { System.out.println("Inside RoundedSquare/draw() method."); } } public class Rectangle implements Shape { public void draw() { System.out.println("Inside Rectangle/draw() method."); } }

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    Factories public abstract class AbstractFactory { Shape getShape(String shapeType) ; } public class ShapeFactory extends AbstractFactory { public Shape getShape(String shapeType){ if(shapeType.equalsIgnoreCase("RECTANGLE")){ return new Rectangle(); }else if(shapeType.equalsIgnoreCase("SQUARE")){ return new Square(); } return null; } }

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    Factories public class RoundedShapeFactory extends AbstractFactory { public Shape getShape(String shapeType){ if(shapeType.equalsIgnoreCase("RECTANGLE")){ return new RoundedRectangle(); }else if(shapeType.equalsIgnoreCase("SQUARE")){ return new RoundedSquare(); } return null; } }

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    Client public class Client { public static void main(String[] args) { AbstractFactory shapeFactory = new ShapeFactory(); //get an object of Shape Rectangle Shape shape1 = shapeFactory.getShape("RECTANGLE"); //call draw method of Shape Rectangle shape1.draw(); //get an object of Shape Square Shape shape2 = shapeFactory.getShape("SQUARE"); //call draw method of Shape Square shape2.draw(); ] //get shape factory AbstractFactory shapeFactory1 = new RoundedShapeFactory(); //get an object of Shape Rectangle Shape shape3 = shapeFactory1.getShape("RECTANGLE"); //call draw method of Shape Rectangle shape3.draw(); //get an object of Shape Square Shape shape4 = shapeFactory1.getShape("SQUARE"); //call draw method of Shape Square shape4.draw(); } }

20. jgs Adapter Convert the interface of a class into another

    interface clients expect

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    GoF Patterns

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    Adapter

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    Example RectangleAdapter + draw Rectangle + draw + draw

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    Client public class Client { public static void main(String[] args) { Shape shape = new RectangleAdapter(new Rectangle(); int x1 = 10, y1 = 20; int x2 = 30, y2 = 60; shape.draw(x1, y1, x2, y2); } }

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    Adapter class RectangleAdapter implements Shape { private Rectangle adaptee; public RectangleAdapter(Rectangle rectangle) { this.adaptee = rectangle; } public void draw(int x1, int y1, int x2, int y2) { int x = Math.min(x1, x2); int y = Math.min(y1, y2); int width = Math.abs(x2 - x1); int height = Math.abs(y2 - y1); adaptee.draw(x, y, width, height); } }

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    Adaptee class Rectangle { public void draw(int x, int y, int width, int height) { System.out.println("Rectangle with coordinate left-down point”); } }

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    Review § Prototype § Composite § Flyweight § Proxy

28. jgs CSE 564 Computer Systems Fundamentals Javier Gonzalez-Sanchez javiergs@asu.edu Fall

    2020 Disclaimer. These slides can only be used as study material for the class CSE564 at ASU. They cannot be distributed or used for another purpose.