java - 有限状态机中的返回语句

Question

谁能告诉我有限状态机状态中的 return 语句的用途是什么？例如，我有一个足球运动员状态的代码:

public class ChaseBall extends State<FieldPlayer> {

    private static ChaseBall instance = new ChaseBall();

    private ChaseBall() {
    }

    //this is a singleton
    public static ChaseBall Instance() {
        return instance;
    }

    @Override
    public void Enter(FieldPlayer player) {
        player.Steering().SeekOn();
        }
    }

    @Override
    public void Execute(FieldPlayer player) {
        //if the ball is within kicking range the player changes state to KickBall.
        if (player.BallWithinKickingRange() && player.isReadyForNextKick()) {
            player.GetFSM().ChangeState(KickBall.Instance());
            return;
        }

        //if the player is the closest player to the ball then he should keep
        //chasing it
        if (player.isClosestTeamMemberToBall()) {
            player.Steering().SetTarget(player.Ball().Pos());

            return;
        }

        //if the player is not closest to the ball anymore, he should return back
        //to his home region and wait for another opportunity
        player.GetFSM().ChangeState(ReturnToHomeRegion.Instance());
    }

    @Override
    public void Exit(FieldPlayer player) {
        player.Steering().SeekOff();
    }
}

我想知道是否有人可以解释 Execute() 方法的前两个 if 语句中的 return 关键字的用途是什么？谢谢

Answer 1

在本例中，它主要是一系列 else if 子句的格式化替代方案。逻辑上等价于

if (<condition>) {
    <code>
} else if (<condition>) {
    <code>
} else {
    <code>
}