jgs CSE 564 Software Design Lecture 17: More Patterns Dr. Javier Gonzalez-Sanchez [email protected] javiergs.engineering.asu.edu | javiergs.com PERALTA 230U Office Hours: By appointment 

jgs 564 00010001 GoF Patterns 

jgs Factory Wrapper of a constructor One entire object to be built in a single method call 

jgs 564 00010001 Abstract Factory 

jgs 564 00010001 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."); } } 

jgs 564 00010001 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; } } 

jgs 564 00010001 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; } } 

jgs 564 00010001 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(); } } 

jgs Test Yourselves 

jgs 564 00010001 Workspace.java (part 1 / 2) 

jgs 564 00010001 User D B A C 

jgs 564 00010001 The System D B A C random 

jgs Chain of Responsibility Avoid coupling the sender of a request to its receiver by giving more than one object a chance to handle the request. 

jgs 564 00010001 Chain of Responsibility 

jgs 564 00010001 Chain of Responsibility // Setup Chain of Responsibility Handler h1 = new ConcreteHandler2(); Handler h2 = new ConcreteHandler2(); Handler h3 = new ConcreteHandler1(); h1.SetSuccessor(h2); h2.SetSuccessor(h3); // Generate and process request int[] requests = { 2, 5, 14, 22, 18, 3, 27, 20 }; foreach (int i=0; i

jgs 564 00010001 Handler abstract class Handler { public abstract void HandleRequest(int request); } class ConcreteHandler1 extends Handler { public override void HandleRequest(int request) { if (request >= 0 && request < 10) { // code here… } else if (successor != null) { successor.HandleRequest(request); } } } 

jgs 564 00010001 Handler class ConcreteHandler2 extends Handler { protected Handler successor; public void setSuccessor(Handler successor) { this.successor = successor; } public override void HandleRequest(int request) { if (request >= 10 && request < 20) { // code here } else if (successor != null) { successor.HandleRequest(request); } } } 

jgs 564 00010001 Chain of Responsibility vs Composite vs Decorator 

jgs Test Yourselves 

jgs 564 00010001 The System D B A C D B A C Clustering TSP -Nearest Neighbor 

jgs 564 00010001 Questions 

jgs CSE 564 Software Design Javier Gonzalez-Sanchez, Ph.D. [email protected] Fall 2021 Copyright. These slides can only be used as study material for the class CSE564 at ASU. They cannot be distributed or used for another purpose.