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Tags: #public

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Design Patterns Video tutorial - Derek Banas
1.

OOP - object oriented programming

class
fields, instance variables ()
methods, functions (parameter->argument <- local variables)
abstract out those features
override or extend methods

property->
getter=accessors
setter=mutators

Is A? versus has A?
Is a dog an animal?
is a dog a cat?
dog has a height?

animal.java

public class Animal {
    private String name;
    private int weight;
    private String sound;

    public void setName(String newName){ name = newName }
    public String getName() { return name; }
    public void setWeight(int newWeight){
        if(newWeight > 0){
            weight = int newWeight;
        } else {
            System.out.println("Weight must be bigger than 0");
        }
    }
    public int getWeight(){ return weight; }

    public void setSound(String newSound){ sound = newSound; }
    public String getName(){ return name; }
}

dog.java

public class Dog extends Animal {
    public void digHole(){
        System.out.println("Dug a hole")
    }

    public Dog(){
        super();

        setSound("Bark")
    }
    public void changeVar(int randNum){
        randNum = 12
        System.out.println("randNum in method: " + randNum) # 12 {: id="12" }
    }
}

cat.java

public class Cat extends Animal {

    public Cat(){
        super();

        setSound("Meow")
    }

workwithanimals.java

public class WorkWithAnimals{

    public static void main(String[] args){
        Dog fido = new Dog();
        fido.setName("Fido")
        System.out.println(fido.getName());

        fido.digHole()
        fido.setWeight(-1)

        int randNum = 10
        fido.changeVar(randNum);
        System.out.println("randNum after method call: " + randNum ); # 10 {: id="10" }


        changeObjectName(fido);
        System.out.println(fido.getName()); # changed {: id="changed" }
    }

    public static void changeObjectName(Dog fido){
        fido.setName("Marcus")
    }

}