Can you create a defensive copy of an object/instance of a class?

[flat tapir]

Findbugs keep giving my error about may expose internal...

[thorny roost]

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TIP: Narrow down your issue to simple and precise questions to maximize the chance that others will reply in here.

[turbid cradle]

If you have a class saving something and want other classes to be able to read that data:

public class SomeClass{
    private List<Something> data=new ArrayList<>();
    public List<Something> getData(){
        return data;
    }
}

but maybe other classes shouldn't change that

other code might do

SomeClass o=new SomeClass();
//...
List<Something> data = o.getData();
data.clear();
``` or similar

and you modified data you haven't modified

you can change getData to return a copy

so that the code using it doesn't modify the original

public List<Something> getData(){
    return new ArrayList<>(data);
}

Then, others would just operate on a copy and cannot just change it

this is called a defensive copy

as it protects against (accidental or unsafe) modifications

[flat tapir]

That's ok but for example I have a controller where I store in a array all the inputs from the keyboard, then linked to this controller another class, in this class I create things like entities that have to get that array of inputs, I cannot pass the controller or that class directly

[turbid cradle]

If it shouldn't be modified by others, you should probably be using a defensive copy

if it is supposed to be modified by others, don't use a defensive copy

just because it is a warning, it doesn't mean you have to do what it suggests

[flat tapir]

I need to fix all the warnings too :/

[turbid cradle]

Why?

[brittle urchin]

rogue PM maybe

[flat tapir]

Maybe not, I'll ask

So for example, if I have a game class where I create all the entities etc. every entity has some components, one of them is an input component that needs the array with all input component, how can I get it without setting the game class into the entities?

I can't pass while creating cuz it updates every frame not something static

[turbid cradle]

?

[thorny roost]

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