以下是一个根据给定的类图编写的Python程序示例，用于在线巴士订票生成车票：

class Ticket:
    def __init__(self, passenger_name, bus_route, seat_number):
        self.passenger_name = passenger_name
        self.bus_route = bus_route
        self.seat_number = seat_number

    def display_ticket(self):
        print("Passenger Name:", self.passenger_name)
        print("Bus Route:", self.bus_route)
        print("Seat Number:", self.seat_number)

class Bus:
    def __init__(self, bus_number, bus_route):
        self.bus_number = bus_number
        self.bus_route = bus_route
        self.seats_available = 30
        self.seats_booked = []

    def book_ticket(self, passenger_name):
        if self.seats_available > 0:
            seat_number = self.get_next_available_seat()
            ticket = Ticket(passenger_name, self.bus_route, seat_number)
            self.seats_booked.append(ticket)
            self.seats_available -= 1
            print("Ticket booked successfully!")
            ticket.display_ticket()
        else:
            print("No seats available on this bus.")

    def get_next_available_seat(self):
        seat_number = 1
        for ticket in self.seats_booked:
            if ticket.seat_number == seat_number:
                seat_number += 1
        return seat_number

# 测试代码
bus = Bus("B001", "Route A")
bus.book_ticket("John")
bus.book_ticket("Mary")

运行上述代码，将生成输出如下：

Ticket booked successfully!
Passenger Name: John
Bus Route: Route A
Seat Number: 1
Ticket booked successfully!
Passenger Name: Mary
Bus Route: Route A
Seat Number: 2

该程序创建了一个Ticket类，表示车票，包含乘客姓名、巴士路线和座位号等属性，并且具有显示车票信息的方法。

另外，该程序还创建了一个Bus类，表示巴士，包含巴士编号、巴士路线、可用座位数和已预订座位列表等属性。Bus类具有预订车票的方法book_ticket，会根据可用座位数生成一个新的Ticket对象，并将其添加到已预订座位列表中。

在测试代码中，首先创建了一个Bus对象bus，表示一辆巴士，其巴士编号为"B001"，路线为"Route A"。然后，通过调用book_ticket方法，预订了两张车票，分别为乘客"John"和"Mary"。每次预订车票成功后，会显示生成的车票信息。

注意：上述代码只是一个示例，具体实现根据个人需求可能会有所不同。