How can I define a variable within an object with another variable

Question

The title might be a little confusing but what I want to know is how can I change the ' b ' part in mainsave.b so that it will define it within the object.

Here is my code so far

public void getItem(int a, String b)
{
    mainsave.b = a;
}

The values are being sent from this piece of code in another class called Story. I want them to be stored in the object of class SaveFile which is what 'mainsave' is

if (command_string.equals("1"))
        {
           try {Thread.sleep(1500);} catch (InterruptedException e) {} 
           System.out.println("You search the shed thouroughly and find an axe but not much else...");
           int item = 1;
           String axe = "axe";
           getItem(item,axe);
           try {Thread.sleep(1500);} catch (InterruptedException e) {}   
           area1();
        }

The error I get when trying to compile the first part is "cannot find symbol - variable b"

"so that it will define it within the object" - Can you elaborate, or at least use fewer pronouns? — Zircon, Apr 21 '16 at 18:36
@Zircon mainsave. b = a should come out to something like mainsave.axe = 1 — Tristan, Apr 21 '16 at 18:38

score 1 · Accepted Answer · answered Apr 21 '16 at 18:38

1

Simply you cannot since Java is a statically typed language. So variables names must realize at compile time.

I don't suggest but possible with reflection coding.

answered Apr 21 '16 at 18:38

Suresh Atta

120,458
37
198
307

So would I have to create a method for each individual item that I want to pass on? – Tristan Apr 21 '16 at 18:40
@Tristan Yes. Overloading. – Suresh Atta Apr 21 '16 at 18:41

score 0 · Answer 2 · answered Apr 21 '16 at 18:43

0

Usually you define getters and setters for each of you fields.

Though it's not recommended, you could achieve this by reflections.

Object a = new A();

Class<?> c = a.getClass();

Field fieldValue = c.getDeclaredField("value");

fieldValue.setInt(a, 10);

Getting and Setting Field Values

answered Apr 21 '16 at 18:43

lkq

2,326
1
12
22

-1, because for as trivial things as storing some data in a SaveFile class nobody should be using Reflection. (nobody should use it for non-trivial things either, for that matter) – RecursiveExceptionException Apr 21 '16 at 18:50
OP could also use ASM to edit the bytecode at runtime to implement non-statically typed languages features in Java. But just because you *can* do it, doesn't mean you *should*. – RecursiveExceptionException Apr 21 '16 at 18:57
Don't be silly. Nobody should do something as stupid as that – RecursiveExceptionException Apr 21 '16 at 18:59
sorry, kinda in a bad mood at the moment – RecursiveExceptionException Apr 21 '16 at 19:01

score 0 · Answer 3 · edited May 23 '17 at 11:59

0

That doesn't work since Java is a Statically-Typed Language unlike JavaScript or Lua.

So,

I would suggest you use some sort of List for actually storing the data instead of a lot of fields in your SaveFile class.

edited May 23 '17 at 11:59

Community

1
1

answered Apr 21 '16 at 18:48

RecursiveExceptionException

581
5
14

How can I define a variable within an object with another variable

3 Answers3

So,