Polymorphism with ArrayList

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Polymorphism with ArrayList

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#1 by (3 votes)

2

I have the Iinterface below and I would like to know how to override the method by passing another object to List because I have 4 classes in my entity, for example the entity classes are cliente , colaborador , produto and serviço and the classes that implement the interface are ClienteDAO , ColaboradorDAO , ServicoDAO , ProdutoDAO Below is an example of this:

public interface ISalaoDAO {

    int save(Object object);
    int update(Object object);
    int remove(Long id);
     List<Cliente> findAll();

}

public class ClienteDAO implements ISalaoDAO{
private static final String SQL_FIND_ALL = 
            "select * from CLIENTE";
public List<Cliente> findAll() {
        Connection conn = DBConnection.getConnection();
        PreparedStatement pstm = null;
        List<Cliente> clientes = new ArrayList<Cliente>();
        ResultSet rs = null;
        try {
            pstm = conn.prepareStatement(SQL_FIND_ALL);
            rs = pstm.executeQuery();
            while(rs.next()){
                Cliente cliente = new Cliente();
                cliente.setId(rs.getLong("ID_CLIENTE"));
                cliente.setCliente(rs.getString("NOME_CLIENTE"));
                cliente.setEnderecoCliente(rs.getString("ENDERECO_CLIENTE"));
                cliente.setTelefoneCliente(rs.getString("TELEFONE_CLIENTE"));
                clientes.add(cliente);
            }
        } catch (SQLException e) {
            try{
                if(conn != null){
                    conn.setAutoCommit(false);
                    conn.rollback();
                }
            }catch(SQLException e1){
                e1.printStackTrace();

            }finally{
                DBConnection.close(conn, pstm, rs);
            }                   
        }   
        return clientes;
    }

java array

asked by anonymous 09.11.2014 / 14:40

1 answer

Group cells case when empty sql Error Building Json of an Object retrieved by Hibernate

score 3 · Answer 1

I've never tried to do it and I do not know if it violates Liskov's replacement principle or something, but I suggest the following:

public interface ISalaoDAO<T> {
    int save(T object);
    int update(T object);
    int remove(Long id);
    List<T> findAll();
}

Here you specify the type of T in the implementing class:

public class ClienteDAO implements ISalaoDAO<Cliente> {
    ...
    public List<Cliente> findAll() {
        ...
    }
}