Dr. Javier Gonzalez-Sanchez javiergs@calpoly.edu www.javiergs.info o ffi ce: 14 -227 CSC 305 Individual Software Design and Development Lecture 17. Chain of Responsabily and Builder

Previously

GoF Patterns 3

Observer 4

Singleton 5

Composite 6

Strategy 7

Examples

Logger 9

Desktop 10

Streams 11

Chain of Responsibility

Chain of Responsibility • Avoid coupling the sender of a request to its receiver by giving more th a n one object a ch a nce to h a ndle the request. 13

Chain of Responsibility 14

Chain of Responsibility vs Composite vs Decorator 15

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

Handler abstract class Handler { public abstract void handleRequest(int request); } class ConcreteHandler1 extends Handler { public void handleRequest(int request) { if (request >= 0 && request < 10) { // code here… } else { // nothing can be done :( } } } 17

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); } } } 18

Fluent-Builder

Fluent-Builder • The Fluent Builder is a builder whose design relies on method chaining. In doing so, it a ims to promote code legibility. 20

Example 21

Fluent-Builder import java.awt.*; public class Client { public static void main(String[] args) { FluentBuilder builder = new BoxFluentBuilder() .setColor(Color.RED) .setSize(20) .setX(10) .setY(20); Product box = ((BoxFluentBuilder)builder).get(); } } 22

Fluent-Builder import java.awt.Color; public interface FluentBuilder { public Builder setColor(Color color); public Builder setSize(int size); public Builder setX(int x); public Builder setY(int y); } 23

Fluent-Builder import java.awt.*; public class BoxFluentBuilder implements FluentBuilder { private Color color; private int size, x, y; public Builder setColor (Color color) { this.color = color; return this; } public Builder setSize(int size) { this.size = size; return this; } public Builder setX(int x) { this.x = x; return this; } public Builder setY(int y) { this.y = y; return this; } public Box get() { return new Box (color, size, x, y); } } 24

GoF Patterns 25

Questions 26

Assignment 03. GUI for Hanoi

Homework You do NOT need all the patterns! Use the tools that better fit

Create a GUI for the Game 29 That was a good move! That is not good, go back Do you want a hint? Move from pole (A,B,C): To pole (A,B,C):

ToDo List Using the GUI provided, integr a te the text-b a sed g a me you cre a ted for Assignment 1 into the interf a ce. Your implement a tion should include the following fe a tures: • Dr a g- a nd-Drop Disk Movement: Implement dr a g- a nd-drop function a lity to a llow users to move disks a cross poles. • Re a l-Time Move V a lid a tion: Ensure re a l-time checks a re in pl a ce to prevent inv a lid moves, such a s pl a cing a l a rger disk on top of a sm a ller one on the s a me pole. • Hint System for Assist a nce: Provide a hint fe a ture to a ssist the user by suggesting the next optim a l move when requested. • Applic a tion of Design P a tterns: Utilize a ppropri a te softw a re design p a tterns to cre a te a structured a nd e ff icient solution. • The f in a l GUI should o ff er a n intuitive experience, m a king it e a sy for users to inter a ct with the g a me while enforcing a ll g a me rules e ff ectively. • 30

CSC 305 Individual Software Design and Development Javier Gonzalez-Sanchez, Ph.D. javiergs@calpoly.edu Summer 2024 Copyright. These slides can only be used as study material for the class CSC305 at Cal Poly. They cannot be distributed or used for another purpose.