门 | GATE-CS-2015(Set 2)|问题11

这道题目要求我们为一个门类定义一些行为。我们需要考虑门的类型、打开、关闭、锁定和解锁的操作。我们可以使用面向对象的概念来完成这道题目。

需求分析

首先，我们需要定义门类。门可以是单开或双开，每种门都有一些共同的行为，如打开、关闭、锁定和解锁。因此，我们可以定义一个门类，然后定义单开门和双开门类继承门类，以处理门的不同类型。

对于门的行为，我们可以使用一个枚举类型来表示每个操作：

public enum DoorOperation {
    OPEN, CLOSE, LOCK, UNLOCK
}

然后，在门类中，我们可以定义一个方法来处理每个操作：

public void performOperation(DoorOperation operation) {
    switch (operation) {
        case OPEN:
            open();
            break;
        case CLOSE:
            close();
            break;
        case LOCK:
            lock();
            break;
        case UNLOCK:
            unlock();
            break;
    }
}

然后，我们可以在门类的子类中重写这些方法来适应不同类型的门。例如，对于单开门，我们只需要实现 open() 和 close() 方法，因为单开门不能被锁定。另一方面，对于双开门，我们需要实现所有四个方法。

代码

下面是门类的基本实现：

public class Door {
    public void open() {
        System.out.println("The door is open now.");
    }

    public void close() {
        System.out.println("The door is closed now.");
    }

    public void lock() {
        System.out.println("The door is locked now.");
    }

    public void unlock() {
        System.out.println("The door is unlocked now.");
    }

    public void performOperation(DoorOperation operation) {
        switch (operation) {
            case OPEN:
                open();
                break;
            case CLOSE:
                close();
                break;
            case LOCK:
                lock();
                break;
            case UNLOCK:
                unlock();
                break;
        }
    }
}

然后，我们可以定义单开门和双开门类：

public class SingleDoor extends Door {
    @Override
    public void open() {
        System.out.println("The single door is open now.");
    }

    @Override
    public void close() {
        System.out.println("The single door is closed now.");
    }
}

public class DoubleDoor extends Door {
    @Override
    public void open() {
        System.out.println("The double door is open now.");
    }

    @Override
    public void close() {
        System.out.println("The double door is closed now.");
    }

    @Override
    public void lock() {
        System.out.println("The double door is locked now.");
    }

    @Override
    public void unlock() {
        System.out.println("The double door is unlocked now.");
    }
}

现在，我们可以创建门对象，并执行一些操作：

public static void main(String[] args) {
    Door door = new SingleDoor();
    door.performOperation(DoorOperation.OPEN);
    door.performOperation(DoorOperation.CLOSE);

    Door doubleDoor = new DoubleDoor();
    doubleDoor.performOperation(DoorOperation.OPEN);
    doubleDoor.performOperation(DoorOperation.LOCK);
    doubleDoor.performOperation(DoorOperation.UNLOCK);
    doubleDoor.performOperation(DoorOperation.CLOSE);
}

输出如下：

The single door is open now.
The single door is closed now.
The double door is open now.
The double door is locked now.
The double door is unlocked now.
The double door is closed now.

总结

通过以上实现，我们学会了如何使用面向对象的概念完成一个简单的门类，以及如何使用继承来处理门的不同类型。我们还学会了如何使用枚举类型来表示门的操作，并在门类中定义方法来执行这些操作。