Enum类型的Java泛型

private Map<? extends Enum, Unit> myMap

createMyClass

public static MyClass <T extends Enum> myClass createMyClass(Class<T> x) {
    MyClass theClass = new MyClass() //constructor is private
    //...
    myMap = new HashMap<T, Unit>();
    for(T t : x.getEnumConstants())
        myMap.put(t, theClass.new Unit(t));
    //...
}

Unit

MyClass

java.util.Map<K,V>

put

? extends java.lang.Enum

T

MyClass.Unit

T extends Enum

Map<? extends Enum, Unit>

Map<Enum, Unit>

Enum

?

public static <T extends Enum<T>> MyClass createMyClass(Class<T> x) {
}