Uppgift 4 - Djurparken

Animal:

import java.util.Random;

public class Animal {
    final String name;
    final int id;
    boolean alive;
    Coordinate coordinate;
    int stomachContent;

    // Constructor
    Animal(String name, int id, Coordinate coordinate) {
        this.name = name;
        this.id = id;
        this.alive = true;
        this.coordinate = coordinate;
        this.stomachContent = 10;
    }

    public void die() {
        if (!this.alive) return;
        this.alive = false;
        System.out.println(this.name + " med id:t " + this.id + " dog.");
    }

    public void move() {
        // Random number
        Random random = new Random();
        int rand = random.nextInt(9);

        // Move to one of the possible directions
        switch (rand) {
            case 0:
                this.coordinate.setX(this.coordinate.x - 1);
                this.coordinate.setY(this.coordinate.y - 1);
                break;
            case 1:
                this.coordinate.setY(this.coordinate.y - 1);
                break;
            case 2:
                this.coordinate.setX(this.coordinate.x + 1);
                this.coordinate.setY(this.coordinate.y - 1);
                break;
            case 3:
                this.coordinate.setX(this.coordinate.x - 1);
                break;
            case 4:
                this.coordinate.setX(this.coordinate.x + 1);
                break;
            case 5:
                this.coordinate.setX(this.coordinate.x - 1);
                this.coordinate.setY(this.coordinate.y + 1);
                break;
            case 6:
                this.coordinate.setY(this.coordinate.y + 1);
                break;
            case 7:
                this.coordinate.setX(this.coordinate.x + 1);
                this.coordinate.setY(this.coordinate.y + 1);
                break;
            default:
                // do nothing (stand still)
                break;
        }
    }

    public void think() {
        if (!this.alive) return;
        this.stomachContent--;
        if (this.stomachContent <= 0) {
            this.die();
            return;
        }
        this.move();
    }

    public double distanceTo(Animal animal) {
        return this.coordinate.distance(animal.coordinate);
    }

    public String toString(){
        return "<" + this.name + ", " + this.id + ", " + this.alive + ", " + this.stomachContent + ", " + this.coordinate + ">";
    }

    // Getters
    public String getName() {
        return name;
    }

    public int getId() {
        return id;
    }

    public Boolean getAlive() {
        return alive;
    }
}

Predator:

public class Predator extends Animal {
    // Constructor
    Predator(String name, int id, Coordinate coordinate) {
        super(name, id, coordinate);
    }

    void eat(Animal animal){
        animal.die();
    }
}

Zebra:

public class Zebra extends Animal {
    // Constructor
    Zebra (String name, int id, Coordinate coordinate) {
        super(name, id, coordinate);
    }
}

Lion:

public class Lion extends Predator {
    // Constructor
    Lion (String name, int id, Coordinate coordinate) {
        super(name, id, coordinate);
    }

    // Overides method so that the lion also roar
    @Override
    public void eat(Animal animal) {
        if (!this.alive || !animal.alive) return;
        super.eat(animal);
        roar();
        this.stomachContent += 10;
    }

    // Roar!
    public void roar() {
        System.out.println(this.name + ": ROOOAAAAAR!!!");
    }
}

Coordinate:

public class Coordinate {
    int x;
    int y;

    // Constructor
    Coordinate(int x, int y) {
        this.x = x;
        this.y = y;
    }

    // Calculates the distance between two coordinates
    public double distance(Coordinate cord) {
        return Math.hypot((double) this.x - cord.x, (double) this.y - cord.y);
    }

    @Override
    public String toString() {
        return "<" + this.x + "," + this.y + ">";
    }

    // Getters
    public int getX() {
        return this.x;
    }

    public int getY() {
        return this.y;
    }

    // Setters
    public void setX(int x) {
        this.x = x;
    }

    public void setY(int y) {
        this.y = y;
    }
}

Zoo:

import java.util.ArrayList;

public class Zoo {
    ArrayList <Animal> animals;
    public int idCounter = 0;
    public boolean run;

    // Constructor
    Zoo() {
        animals = new ArrayList<Animal>();
        init();
        run = true;
    }

    // creates some animals
    private void init() {
        animals.add(new Lion("Simba", idCounter, new Coordinate(0, 0)));
        increaseAnimalId();

        animals.add(new Lion("Mufasa", idCounter, new Coordinate(0, 0)));
        increaseAnimalId();

        animals.add(new Zebra("Marty", idCounter, new Coordinate(0, 0)));
        increaseAnimalId();

        animals.add(new Zebra("Stripe", idCounter, new Coordinate(0, 0)));
        increaseAnimalId();

        animals.add(new Zebra("Zeb", idCounter, new Coordinate(0, 0)));
        increaseAnimalId();

        animals.add(new Zebra("Zanzabar", idCounter, new Coordinate(0, 0)));
        increaseAnimalId();

        animals.add(new Zebra("Zecar", idCounter, new Coordinate(0, 0)));
        increaseAnimalId();
    }

    // Increase id counter
    public void increaseAnimalId() {
        this.idCounter++;
    }

    // Loops ticks one per second and runs the logic in think()
    public void run() throws InterruptedException {
        while (run) {
            for (int i = 0; i < this.animals.size(); i++) {
                // Think methods for animals
                this.animals.get(i).think();
            }

            // Think method for zoo.
            think();

            // Print zoo object
            System.out.println(this);

            // Removes all dead animals
            removeDead();

            // Check if all animals are dead
            if(isDone()){
                this.run = false;
            }
            Thread.sleep(1000);
        }
    }

    // Handles the logic
    public void think() {
        // Iterate through all animals
        for (int i = 0; i < this.animals.size(); i++) {
            // For each lion
            if (this.animals.get(i) instanceof Lion && this.animals.get(i).alive) {
                // Check if zebra and Lion have the same coordinate
                for (int j = 0; j < this.animals.size(); j++) {
                    if (this.animals.get(j) instanceof Zebra && this.animals.get(j).alive) {
                        double distance = this.animals.get(i).distanceTo(this.animals.get(j));
                        if (distance == 0) {
                            ((Lion) this.animals.get(i)).eat(this.animals.get(j));
                        }
                    }
                }
            }
        }
    }

    /* removes all dread animals. Observe that we loop backwards
     * so that the indices will work even if we remove one object.
    */
    public void removeDead() {
        for (int i = this.animals.size()-1; i >= 0; i--) {
            if(!this.animals.get(i).alive) {
                this.animals.remove(i);
            }
        }
    }

    // Check if any animal is alive
    public boolean isDone() {
        for (Animal animal : this.animals) {
            if (animal.alive) {
                return false;
            }
        }
        return true;
    }

    public String toString() {
        String str = "";
        for (int i = 0; i < this.animals.size(); i++) {
            str += this.animals.get(i).toString() + " ";
        }
        return str;
    }
}

Huvudskriptet:

public class Uppgift4 {
    public static void main(String[] args) throws InterruptedException {
        Zoo zoo = new Zoo();
        zoo.run();
    }
}

Diskussion:

Försök att gå igenom uppgifterna igen och jämför med dina egna klasser och metoder. Har du gjort på ett annat sätt? Grymt bra!

Det finns inte ett rätt svar och många gånger kan man lösa uppgiften på flera sätt. Det man ska ta med sig från denna uppgift är hur man kan skapa subklasser från en klass (parent) och sedan overridea metoder inuti dessa subklasser så att subklassen får ett annat beteende.