OnJava8-Examples/typeinfo/FamilyVsExactType.java
Bruce Eckel 88dbdbbbcb update
2015-05-18 23:05:30 -07:00

50 lines
1.6 KiB
Java

//: typeinfo/FamilyVsExactType.java
// The difference between instanceof and class
package typeinfo;
import static net.mindview.util.Print.*;
class Base {}
class Derived extends Base {}
public class FamilyVsExactType {
static void test(Object x) {
print("Testing x of type " + x.getClass());
print("x instanceof Base " + (x instanceof Base));
print("x instanceof Derived "+ (x instanceof Derived));
print("Base.isInstance(x) "+ Base.class.isInstance(x));
print("Derived.isInstance(x) " +
Derived.class.isInstance(x));
print("x.getClass() == Base.class " +
(x.getClass() == Base.class));
print("x.getClass() == Derived.class " +
(x.getClass() == Derived.class));
print("x.getClass().equals(Base.class)) "+
(x.getClass().equals(Base.class)));
print("x.getClass().equals(Derived.class)) " +
(x.getClass().equals(Derived.class)));
}
public static void main(String[] args) {
test(new Base());
test(new Derived());
}
} /* Output:
Testing x of type class typeinfo.Base
x instanceof Base true
x instanceof Derived false
Base.isInstance(x) true
Derived.isInstance(x) false
x.getClass() == Base.class true
x.getClass() == Derived.class false
x.getClass().equals(Base.class)) true
x.getClass().equals(Derived.class)) false
Testing x of type class typeinfo.Derived
x instanceof Base true
x instanceof Derived true
Base.isInstance(x) true
Derived.isInstance(x) true
x.getClass() == Base.class false
x.getClass() == Derived.class true
x.getClass().equals(Base.class)) false
x.getClass().equals(Derived.class)) true
*///:~