Question

我有以下ruby类：

class Money
  attr_accessor :amount, currency

  def initialize(amount, currency)
    @amount = amount
    @currency = currency
  end
end

假设我创建了一个类的实例：

money = Money.new(0, 'BR')

很明显，我不能创建金额小于或等于0的钱。在这种情况下，我想为我的班级创建一个自定义例外。在纯ruby应用程序中执行此操作的最佳方法是什么？

Answer 1

您也可以在Money类中创建它，如下所示：

class Money
  InvalidAmountError = Class.new(StandardError)

  attr_accessor :amount, :currency

  def initialize(amount, currency)
    raise InvalidAmountError, "Amount must be greater than 0" if amount <= 0

    @amount = amount
    @currency = currency
  end
end

测试它：

> Money.new(0, 'BR')
> Money::InvalidAmountError: Amount must be greater than 0

Answer 2

<script src="https://cdnjs.cloudflare.com/ajax/libs/fabric.js/1.7.12/fabric.min.js"></script>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<canvas id="c" width="200" height="200"></canvas>
<button id="init">
INIT
</button>
<button id="move">
MOVE
</button>

结帐this blog了解更多详情

纯Ruby应用程序中的异常

2 个答案: