Doubt referring to using add in LinkedList, java

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Doubt referring to using add in LinkedList, java

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#1 by (1 votes)

1

I have LinkedList<CasosPossiveis> casos = new LinkedList<>(); and CasosPossiveis objeto = new CasosPossiveis(); . Within for , after this declaration, I make a: casos.add(objeto); , after modifying the object data. What happens, however, is that when I start my casos , the values in all the positions in the list are the same because it seems that objeto was passed as a reference in casos.add(objeto); . What I want to do is that every time I give .add(objeto) , a new value is added and not modified any more, if I modify the objeto . How can I do this?

Code of for :

for (int i = 0; i < texto.size(); i++) {
        String[] aux = texto.get(i).split(" ");

        if (aux.length > 2) {
            cont = 0;

            if (pratos.size() != 0) {
                System.out.println("ta diferente: " + pratos.size());
                objeto.setPratosPossiveis(pratos);
                System.out.println("um pratro add: ");

                casos.add(objeto); //PROBLEMA: ta recebendo sempre o edenreço de objeto e mudando tudo

                System.out.println(casos.get(0).getPratosPossiveis().get(0).get(0));


                pratos.clear();
            }

            objeto = new CasosPossiveis();
            System.out.println("NumerO2: "+objeto.getNumeroDias());
            objeto.setNumeroDias(Integer.parseInt(aux[0]));
            objeto.setNumeroPratos(Integer.parseInt(aux[1]));
            objeto.setOrcamento(Integer.parseInt(aux[2]));

        } else {
            pratos.add(new LinkedList<>());
            pratos.add(new LinkedList<>());
            System.out.println("Valor do cont: " + cont);
            pratos.get(cont).add(Integer.parseInt(aux[0]));
            pratos.get(cont).add(Integer.parseInt(aux[1]));
            System.out.println("o que adicionei 1: " + pratos.get(cont).get(0));
            System.out.println("o que adicionei 2: " + pratos.get(cont).get(1));
            cont++;
        }
    }
  }
    System.out.println("tamanho q ficou: " + casos.size());
    for (int i = 0; i < casos.size(); i++) {
        System.out.println("aqui: " + casos.get(i).getPratosPossiveis().size());
        for (int j = 0; j < casos.get(i).getPratosPossiveis().size(); j++) {
            System.out.println("ue");
            System.out.println(casos.get(i).getPratosPossiveis().get(i));
        }

    }

Explanation: texto.size() has data from a file. Each position is a file line. If the line has more than two int s, I add what I had in the object in my ArrayList of objects, "clean" the object and start adding values back into the object until I find a new line with more and two int s.

java

asked by anonymous 25.11.2017 / 16:13

1 answer

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score 1 · Accepted Answer

Change the type of pratos to List<List<Integer>> . Try this:

    for (String linha : texto) {
        String[] aux = linha.split(" ");

        if (aux.length > 2) {
            objeto = new CasosPossiveis();
            System.out.println("Numero 2: " + objeto.getNumeroDias());
            objeto.setNumeroDias(Integer.parseInt(aux[0]));
            objeto.setNumeroPratos(Integer.parseInt(aux[1]));
            objeto.setOrcamento(Integer.parseInt(aux[2]));
            pratos = new ArrayList<>();
            objeto.setPratosPossiveis(pratos);
            casos.add(objeto);
        } else {
            int a = Integer.parseInt(aux[0]);
            int b = Integer.parseInt(aux[1]);
            List<Integer> linhaPratos = Arrays.asList(a, b);
            pratos.add(linhaPratos);
        }
    }
}

System.out.println("Tamanho que ficou: " + casos.size());
for (CasosPossiveis caso : casos) {
    System.out.println("aqui: " + caso.getPratosPossiveis().size());
    for (List<Integer> pratosPossiveis : caso.getPratosPossiveis()) {
        System.out.println("ue");
        System.out.println(pratosPossiveis);
    }
}

In the last System.out.println , you were using i twice instead of i and j . However, using enhanced-for syntax makes it much easier to navigate through the list and avoid having to use that many indexes.

The variable cont can be deleted.