Can you set a multi-object array and call a method from it?

Question

To be exact, I'm curious as to whether an Object[] array is capable of storing and accessing other objects' methods. Here's a little example of what I'm trying to achieve.

//declare an array of *different* objects
private static Object[] function = {new Object1(),
                                    new Object2()}; 
//calls method(getNumber) from Object1()
function[0].getNumber();

Since I already found out that you can stack same objects into an array, I want to figure out if its possible to do so with different methods without using ArrayList. Just curious, so if you think there isn't a way to do this just tell me so, thanks :)

Its probably easier to just call it directly from the object while declaring them separately, right? — Tan Poh Heng, Jul 24 '17 at 08:28
You can do it, with a cast: `(Object1)function[0].myObjectMethod();` — Ricardo, Jul 24 '17 at 08:29
Why does casting work? Is it because the array itself is only declared as an Object[] type array? Sry bout these qns, i legit just started coding less than half a year ago :P — Tan Poh Heng, Jul 24 '17 at 08:39
Any object array, let's say, MyObject[], is, in it's most basic concept a list of Object with reference to MyObject — Ricardo, Jul 24 '17 at 08:45
Casting works because this is done at runtime. Not at the compile-time. So, it will case your `Object` into the thing that you are expecting here. — Yuri, Jul 24 '17 at 08:54

score 1 · Accepted Answer · answered Jul 24 '17 at 08:30

1

I am not sure what you are asking, but you should cast before calling a method on the plain object. Instead of this:

function[0].getNumber();

You should do something like this:

((MyType) function[0]).getNumber();

answered Jul 24 '17 at 08:30

Yuri

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didn't know casting could be used like this, Thanks – Tan Poh Heng Jul 24 '17 at 08:33
Also, please take a look at generics :) https://stackoverflow.com/a/2501513/2928710 – Yuri Jul 24 '17 at 08:38
If the answer hasn't helped don't hesitate to ping :) – Yuri Jul 24 '17 at 08:38

score 0 · Answer 2 · answered Jul 24 '17 at 08:36

If the methods you want to call are the same for all the objects and you control their classes, you should extract the methods to a interface, and let the classes implement it.

This way you could have a CommonInterface[] array...

public CommonInterface { Number getNumber(); }

CommonInterface[] function = { new Object1(), new Object2() };
function[1].getNumber()

Can you set a multi-object array and call a method from it?

2 Answers2