Question

I hope this won’t sound like a stupid question.

I have a class A and a class B. Now the only thing B has is a String ID.
Now I can have multiple objects A that each can have 0 or more objects of type B.
These are contained in a HashMap(ID,someData) each class A has.

What I want to do is each time I add a new ID in class A to check whether there already
is a on object of Type B with the same ID in any of the other class A objects I have, and if not, create a new B object.

Hope this makes sense. If what I ask is wrong is some way, please be kind enough to explain
how is this a bad practice or conceptualy wrong.

Thanks a lot.

EDIT:To be more clear,in my case, it is not desireable to share the HashMap(ID,someData) for all my objects as for example let’s say A is a Course class,Or Catalogue, or Bank etc. Each A class may share some students/clients but each A class may contain different class B objects.

Answer 1

It’s not bad practice, it seems like you’re implementing the Instance Manager Pattern.

• Ability to look up one or more instances (via a key) of the managed object(s). If only one managed object, then a key is not necessary.