I have some Map 0f Map 0f List
I created such interface for shorthand it
public interface ShortName extends Map<String, Map<String, List<String>>>
But when I try to instantiate real object it give me ClassCastExcpetion
ShortName testObj = (ShortName) new HashMap<String, Map<String, List<String>>>();
Is there any way to make short type for Map
Java doesn't have a concept of type aliasing (see This question), however you can make a new class, of a different type, which extends your Map;
class NewType extends HashMap<String, Map<String, List<String>>>
But this isn't a "shorthand" for that type, it's a new type altogether - so casting won't work etc.
This is a way to get a shorthand to work partly. You need to implement ShortName to make ShortName cast work.
You can do public static class NewType extends HashMap<String, Map<String, List<String>>> implements ShortName {}. And then you can use the cast to ShortName as in ShortName testObj = (ShortName) new NewType();
import java.util.Map;
import java.util.HashMap;
import java.util.List;
public class MyClass {
public static void main(String args[]) {
ShortName testObj = (ShortName) new NewType();
System.out.println("ok");
}
public interface ShortName extends Map<String, Map<String, List<String>>> {
}
public static class NewType extends HashMap<String, Map<String, List<String>>> implements ShortName {}
}
