How to find type without using instanceof?

Question

I have a List of interface type Criteria within my class Query.

List criteria = new ArrayList

        

Answer 1

An interface is halfway to the strategy pattern! To vary the logic based on type, push it behind the interface if possible, such that Criteria has a doLogic(). You can pass that method whatever parameters you might need to alter in the calling code, or return new information - that is very implmentation specific and hard to advice on from the code in question.

If all goes well, your calling code ends up

for (Criteria c : criteria) {
    c.doLogic();
}