异常纯Ruby应用程序

Question

我有以下的Ruby类：

class Money 
    attr_accessor :amount, currency 

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

比方说，我创建一个类像的一个实例：

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

很明显，我不应该能够创建一个金额小于或等于0的金额。在这种情况下，我想为我的课程创建一个自定义例外。在纯ruby应用程序中完成它的最佳方式是什么？

Answer 1

你也可以内部Money类中创建，就像这样：

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

class InvalidCurrency < StandardError 
    ... some logic 
end 

class Money 
    attr_accessor :amount, currency 

    def initialize(amount, currency) 
    raise InvalidCurrency unless amount > 0 
    @amount = amount 
    @currency = currency 
    end 
end 

结账this blog更多细节