Independent Work!

High-Quality Work!

Prototype

means hands-on work!

https://cs410.net/standup/

Meaningful Names

Small Functions

Modular Functions

Function Arguments

Code Formatting

Comments

Object Oriented

Constructor

Instances / Instance Variables

Getters / Setters

Static Methods

Singleton Pattern

same instances!

Restricts to only one instance of a class!

But why ?!

Singleton Pattern

Database

Logger

db = Database.getInstance();
db.search('something');

db = Database.getInstance();
db.add(new_product);

db = Database.getInstance();
db.delete(new_product);

Logger.print('User logged in.');

Logger.print('Product deleted.');

db = new Database();
db.search('something');

db = new Database();
db.add(new_product);

logger = new Logger();
logger.print('Product deleted.');

logger = new Logger();
logger.print('User logged in.');

class Circle:
    
    instance = None
    
    def __init__(self):
        '''
        Constructs a circle.
        '''
        self.__radius = 7 # this is private
        self.__radius2 = 1
        
        print('called constructor')
        
    def setRadius(self, radius):
        
        if radius == 7 or radius == 8:
        
            self.__radius = radius
        
    def getRadius(self):
        
        return self.__radius
        
    def getRadii(self):
        '''
        Returns a list of both values.
        '''
        return [self.__radius, self.__radius2]
        
    def draw(self):
        print('O'*self.radius)
        
    @staticmethod
    def getInstance():
        
        if Circle.instance == None:
            Circle.instance = Circle()
            
        return Circle.instance

public final class Circle {

    private static final Circle INSTANCE = 
      new Circle();

    private Circle() {}

    public static Circle getInstance() {
        return INSTANCE;
    }
}

Lazy loading!

Hands-on Series!