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应该是四个吧,
door, genericdoor, alarm,alarmdoor
interface Door {
void open();
void close();
}
abstract class GenericDoor implements Door{
abstract void open();
abstract void close();
}
interface Alarm {
void alarm();
}
class AlarmDoor extends GenericDoor implements Alarm {
void open() { … }
void close() { … }
void alarm() { … }
} |
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