40 lines
810 B
Java
40 lines
810 B
Java
// generics/FactoryConstraint.java
|
|
// (c)2016 MindView LLC: see Copyright.txt
|
|
// We make no guarantees that this code is fit for any purpose.
|
|
// Visit http://mindviewinc.com/Books/OnJava/ for more book information.
|
|
|
|
interface FactoryI<T> {
|
|
T create();
|
|
}
|
|
|
|
class Foo2<T> {
|
|
private T x;
|
|
public <F extends FactoryI<T>> Foo2(F factory) {
|
|
x = factory.create();
|
|
}
|
|
// ...
|
|
}
|
|
|
|
class IntegerFactory implements FactoryI<Integer> {
|
|
@Override
|
|
public Integer create() {
|
|
return 0;
|
|
}
|
|
}
|
|
|
|
class Widget {
|
|
public static class Factory implements FactoryI<Widget> {
|
|
@Override
|
|
public Widget create() {
|
|
return new Widget();
|
|
}
|
|
}
|
|
}
|
|
|
|
public class FactoryConstraint {
|
|
public static void main(String[] args) {
|
|
new Foo2<>(new IntegerFactory());
|
|
new Foo2<>(new Widget.Factory());
|
|
}
|
|
}
|