Trabajo N°4 Ejercicio 2

// Clase Lista
public class List<T> {

    private Node<T> head;
    private Node<T> tail;

    public List() {

        this.head = null;
        this.tail = null;
    }

    public boolean getIsEmpty() {
        return this.head==null;
    }

    public void AddToHead (T item) {

        if (getIsEmpty()) {

            this.head = this.tail = new Node<T>(item,null);

        }
        else {

            Node<T> temp = new Node<T>(item,null);
            temp.setNext(this.head);
            this.head = temp;

        }
    }

    public void AddToTail(T item) {

        if (getIsEmpty()){

            this.head = this.tail = new Node<T>(item, null);

        }else{

            Node<T> temp = new Node<T>(item, null);
            this.tail.setNext(temp);
            this.tail = temp;

        }

    }

    public T RemoveFromHead() {
        if(getIsEmpty()){
            throw new RuntimeException("La lista esta vacia...");
        }

        T item=this.head.getItem();//toma el elemento que esta en el primer nodo
        this.head=this.head.getNext();//avanza el primer nodo al siguiente

        if(this.head==null){//si no hay mas nodos
            this.tail=null;//vaciar la lista
        }
        return item;
    }

    public T RemoveFromTail() {
        if(getIsEmpty()){
            throw new RuntimeException("La lista esta vacia");
        }
        T item = this.tail.getItem();

        if(this.head.getNext()==null){//hay un unico nodo

            this.head = this.tail =null;//vacía la lista

        }else{

            Node<T> skip = new Node<T>();
            skip = this.head;
            for(; skip.getNext().getNext() != null; skip = skip.getNext()){}//recorre la lista mientras haya dos nodos mas
            this.tail = skip;//skip es el penultimo nodo que ahora sera el ultimo
            this.tail.setNext(null);

        }
        return item;//regresa el elemento
    }

    public boolean Contains(T item){
        for(Node<T> skip=this.head; skip != null; skip = skip.getNext()){
            if (item == skip.getItem()) {
                return true;
            }
        }
        return false;
    }

    public void Mostrar(){
        for(Node<T> skip=this.head; skip != null; skip = skip.getNext()){
            System.out.printf("%s ", skip.item.toString());
            System.out.println("\n---------------------------------------");
        }
    }
}

// Clase Nodo
public class Node<T> {

    public T item;
    private Node<T> next;

    public Node() {

        this.item = null;
        this.next = null;

    }

    public Node(T item) {

        this.item = item;
        this.next = null;

    }

    public Node(T item, Node<T> next) {

        this.item = item;
        this.next = next;

    }

    public T getItem() {
        return item;
    }

    public void setItem(T item) {
        this.item = item;
    }

    public Node<T> getNext() {
        return next;
    }

    public void setNext(Node<T> next) {
        this.next = next;
    }

}

// Clase Producto
public class Product {

    private int code;
    private String description;
    private String expirationDate;
    private double salePrice;


    public Product(int code, String description, double salePrice, String expirationDate) {
        this.code = code;
        this.description = description;
        this.salePrice = salePrice;
        this.expirationDate= expirationDate;
    }

    public int getCode() {
        return code;
    }

    public void setCode(int code) {
        this.code = code;
    }

    public String getDescription() {
        return description;
    }

    public void setDescription(String description) {
        this.description = description;
    }

    public String getExpirationDate() {
        return expirationDate;
    }

    public void setExpirationDate(String expirationDate) {
        this.expirationDate = expirationDate;
    }

    public double getSalePrice() {
        return salePrice;
    }

    public void setSalePrice(float salePrice) {
        this.salePrice = salePrice;
    }

    @Override
    public String toString() {
        return "\nCodigo: "+this.code +" \nDescripcion: "+this.description+" \nPrecio: $"+((Double)this.salePrice).toString()+
                "\nFecha de Expiración: "+ this.expirationDate;
    }

}

// Main
import java.util.Scanner;
import java.util.Random;

public class TP04E2 {

    public static void main(String[] args) {
        TP04E2 programa = new TP04E2();
        programa. execute();
    }

    private void execute() {
        List<Product> productos = new List<>();
        Scanner t = new Scanner(System.in);
        Random rand = new Random();
        int op,cant;

        do{
            System.out.println("************************MENU************************");
            System.out.println("1-Agregar Productos al principio de la lista");
            System.out.println("2-Agregar Productos al final de la lista");
            System.out.println("3-Eliminar Producto desde el principio de la lista");
            System.out.println("4-Eliminar Producto desde el final de la lista");
            System.out.println("5-Mostrar la lista de Productos");
            System.out.println("0-Salir");
            System.out.print("Eliga una opcion: ");
            op=t.nextInt();

            switch (op){
            case 1:
                System.out.print("Ingrese cantidad de productos a agregar: ");
                cant = t.nextInt();
                for (int i=0; i<cant;i++){
                    productos.AddToHead(new Product(Entero(10000,20000),Descripcion(),(rand.nextDouble()+0.1)*40,FechaExpiracion()));
                }
                break;

            case 2:
                System.out.print("Ingrese cantidad de productos a agregar: ");
                cant = t.nextInt();
                for (int i=0; i<cant;i++){
                    productos.AddToTail(new Product(Entero(10000,20000),Descripcion(),Entero(20,40),FechaExpiracion()));

                }
                break;

            case 3:
                System.out.println("\n---------------------------------");
                System.out.println("Producto eliminado del principio: "+ "\n" + productos.RemoveFromHead());
                System.out.println("\n---------------------------------");
                break;

            case 4:
                System.out.println("\n---------------------------------");
                System.out.println("Producto eliminado del final: "+ "\n" + productos.RemoveFromTail());
                System.out.println("\n---------------------------------");
                break;

            case 5:
                System.out.println("\n*************************\nListado de Productos: ");
                productos.Mostrar();
                System.out.println();

                break;

            case 6:
                System.out.println("Fin del Programa...");
                break;
          }

        }while (op!=0);

        t.close();
    }



    private int Entero(int minimo, int maximo) {
        int num=(int)Math.floor(Math.random()*(minimo-(maximo+1))+(maximo+1));
        return num;
    }

    private String Descripcion() {
        int al = Entero(1,4);
        switch (al) {
        case 1:
            return "Gaseosa";
        case 2:
            return "Galleta";
        case 3:
            return "Leche";
        case 4:
            return "Mayonesa";
        }
        return "";
    }

    public String FechaExpiracion() {
        int year = Entero(1990,2020);
        int month = Entero(1,12);
        int day;
        switch (month){
        case 2: day = Entero(1,28);
                break;
        default:  day = Entero(1,30);
                break;
        }
        return day+"/"+month+"/"+year;
    }

}