JAVA - Use method from another method class

Question

I have 2 classes; The first has this code:

public class Artigo {

private String descricao;
private double preco;
private int stockCorrente;

public Artigo(String descricao, double preco){
    Artigo(descricao, preco, 0);

}
private void Artigo(String descricao, double preco, int stockCorrente){
    this.descricao = descricao;
    if (preco < 0 || stockCorrente < 0) {
        System.out.println("Erro: Valores negativos.");
        System.exit(0);
    } else
        this.preco = preco;
        this.stockCorrente = stockCorrente;
}
public String getDescricao(){
    return descricao;
}
public double getPreco(){
    return preco;
}
public void setPreco(double preco){
        this.preco = preco;
}
public int getStockCorrente(){
    return stockCorrente;
}
public boolean isStockEnough(int nUnits){
    if (stockCorrente < nUnits){
        return false;
    }else{
        return true;
    }
}
public boolean sell(int nUnits){
    if (isStockEnough(nUnits)){
        stockCorrente = stockCorrente - nUnits;
        return true;
    }else{
        return false;
    }
}
public void recharge(int nUnits){
    stockCorrente = nUnits;
}
public boolean equals(Artigo otherProducts){
    return this.descricao.equalsIgnoreCase(otherProducts.descricao);
}
public String toString(){
    return descricao + ", preço: " + preco + ", stock: " + stockCorrente;
}

And then my other class:

public class Pack {

private String descricao;
private int nArtigos;
private double DESCONTO;

public Pack(String descricao, double desconto){
    this.descricao = descricao;
    this.DESCONTO = desconto; 
}
public String getDescricao(){
    return descricao;
}   
public int getnArtigos(){
    return nArtigos;    
}
public double getDesconto(){
    return DESCONTO;
}
public int getStockCorrente(){
    return stockCorrente;
}
public boolean equals(Pack otherpacks){
    return this.descricao.equalsIgnoreCase(otherpacks.descricao);
}
public String toString(){
    return descricao + " com os artigos [ " + " ], com desconto de " + DESCONTO + ", com preco de " + "PRECO" + ", com stock corrente de " + "STOCK"   ;
}
public boolean existArtigo(Artigo otherProducts){
}
public boolean addArtigo(Artigo newArtigo){ 
}
public boolean haveStock(int nUnits){   
}
public boolean sell(int nUnits){    
}
public double getPreco(){   
}

In this class, all the methods are required and needed. The biggest part of them are empty because I don't know what to do in there. I mean, I know what to do, what I don't know it HOW to do.

The request is: Add articles to the pack, get the name and the current stock of each. Here I need to get them connecting with the methods of the other class, right? But How?

Answer 1

your problem is accessing one class data into other class this can be done by using get method even you can set data by keeping set Method. ex:

class A
{
private int price;

public int getPrice()
{
return price;
}

public void setPrice()
{
this.price=price;
}
}

Now if i want to access price data in Class B then

class B
{
//create object of class A in any method where you want to access price data
A a=new A();
int price =a.getPrice();
}

Answer 2

you should declare a object Artigo in Pack

private Artigo artigo;

then you could initialize this object in constructor Pack

public Pack(String descricao, double desconto){
artigo =new Artigo(descricao,desconto);
this.descricao = descricao;
this.DESCONTO = desconto;
}

after that you could use method of artigo by

artigo.sell(1);

as you want to

Answer 3

or you could extend from base class

public class Pack extends Artigo{
    public Pack(String descricao, double desconto){
            super(descricao,desconto);
}
}

if you want to access method of base class you just type super.methodname;