OnJava8-Examples/generics/ClassTypeCapture.java

// generics/ClassTypeCapture.java
// (c)2021 MindView LLC: see Copyright.txt
// We make no guarantees that this code is fit for any purpose.
// Visit http://OnJava8.com for more book information.

class Building {}
class House extends Building {}

public class ClassTypeCapture<T> {
  Class<T> kind;
  public ClassTypeCapture(Class<T> kind) {
    this.kind = kind;
  }
  public boolean f(Object arg) {
    return kind.isInstance(arg);
  }
  public static void main(String[] args) {
    ClassTypeCapture<Building> ctt1 =
      new ClassTypeCapture<>(Building.class);
    System.out.println(ctt1.f(new Building()));
    System.out.println(ctt1.f(new House()));
    ClassTypeCapture<House> ctt2 =
      new ClassTypeCapture<>(House.class);
    System.out.println(ctt2.f(new Building()));
    System.out.println(ctt2.f(new House()));
  }
}
/* Output:
true
true
false
true
*/