Question

Basically I want to check if a class is instance of the provided interface.

I have a method with this signature:

public ICard draw(Class<? extends ICardType> type)

Then I tried to do this but it is marked as an error;

if (deck.get(i) instanceof type)

NetBeans gives this as the error:

cannot find symbol
symbol: class type
location: class simple.marauroa.client.extension.cardgame.impl.DefaultDeck

I even tried this from one of the other questions:

deck.get(i).isAssignableFrom(type)

I saw questions like: Checking programmatically if a .class file extends particular class and How to check instanceof on an argument that is a Class object? but they didn’t fit my scenario.

Any hints or ideas? I know I’m doing a dumb mistake somewhere.

Answer 1

I think you just want

if (type.isInstance(deck.get(i)))

From the documentation:

Determines if the specified Object is assignment-compatible with the object represented by this Class. This method is the dynamic equivalent of the Java language instanceof operator. The method returns true if the specified Object argument is non-null and can be cast to the reference type represented by this Class object without raising a ClassCastException. It returns false otherwise.