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how to check null values with double

4248376
4248376 Member Posts: 1
edited May 8, 2020 3:13PM in New To Java

Hello guys,

I think in In java double is a primitive type which can not be null but I created a small code which requests using the JOptionPane.showInputDialog box some parameters which I send to a second class to increase a salary value (I have parse to double)

If I cancel one request, I get an error, so I want to handlded that exception without stop the progrma

THis is my code

for(empleados e: misempleados)

{

double enter = Double.parseDouble(JOptionPane.showInputDialog("en ter the %:"));

e.set_increaseSalary(enter);

}

My idea was probably use some sort of enter ==null but I found this is not possible. I want that if I cancel instead to press OK, the program still keep running. In fact, I have noticed a second issue. If I introduce a values different to numbers, I got also an error because I have parse to double.

How could I handle that?

Any idea?

I will appreciate any help

more information below:

Please, follow the complete code (this is a simple code just to test POO)

The main Class is empelado and the second Class is empelados

in the second class we have a constructor empleados which receives these values

(String nam, double salar, int year1, int month1, int day )

then, you ahve all the getters and setters that modify and return values

package poo;

import javax.swing.JOptionPane;

public class main_empleado {

public static void main(String[] args) {

// TODO Auto-generated method stub

/*

empleados empleado1 = new empleados("Paco Gomez", 85000, 1990 , 12, 17);

empleados empleado2 = new empleados("Maria Pepa", 85000, 1991 , 11, 10);

empleados empleado3 = new empleados("Loco Viejo", 85000, 1992 , 8, 12);

empleado1.set_increaseSalary(5);

empleado2.set_increaseSalary(5);

empleado3.set_increaseSalary(5);

System.out.println("Nombre :" + empleado1.getName() + " Sueldo: " + empleado1.getSalary()

+ " Fecha de Alta: " + empleado1.getDateContract());

System.out.println("Nombre :" + empleado2.getName() + " Sueldo: " + empleado2.getSalary()

+ " Fecha de Alta: " + empleado2.getDateContract());

System.out.println("Nombre :" + empleado3.getName() + " Sueldo: " + empleado3.getSalary()

+ " Fecha de Alta: " + empleado3.getDateContract());

*/

empleados[] misempleados = new empleados[4];

misempleados[0] = new empleados("Paco Gomez", 85000, 1990 , 12, 17);

misempleados[1] = new empleados("Maria Pepa", 85000, 1991 , 11, 10);

misempleados[2] = new empleados("Loco Viejo", 85000, 1992 , 8, 12);

misempleados[3] = new empleados("Nuevo empleado");

for(empleados e: misempleados)

{

double enter = Double.parseDouble(JOptionPane.showInputDialog("enter the %:"));

e.set_increaseSalary(enter);

}

for(empleados e: misempleados)

{

System.out.println("Name : " + e.getName() + " Salary: " + e.getSalary() +

" Fecha de Alta: "+ e.getDateContract() );

}

}

}

*********************

package poo;

import java.util.Date;

import java.util.GregorianCalendar;

public class empleados {

//constructor

public empleados(String nam, double salar, int year1, int month1, int day )

{

name = nam;

salary = salar;

//the month is subtracted with 1 because the calendar begin in 0, so January is 0

GregorianCalendar calendario = new GregorianCalendar(year1, month1-1, day);

altaContrato = calendario.getTime();

}

public empleados(String nam)

{

this(nam, 20000,2000,01,01);

}

//method getter return name

public String getName()

{

return name;

}

//method getter salary

public double getSalary()

{

return salary;

}

//method getter return DateContract

public Date getDateContract()

{

return altaContrato;

}

//setter increase salary

public void set_increaseSalary(double porcentage)

{

double increase = salary*porcentage/100;

salary+= increase;

}

//properties

private String name;

private double salary;

private Date altaContrato;

}

Answers

  • nihitthakkar
    nihitthakkar Member Posts: 123 Blue Ribbon

    Double is a primitive type in Java which can not be null. You can check null using Double wrapper class in Java.

    Change the double to it's wrapper class Double and check with == for null. double dbl=ParentBean. getChildBean()

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