在方法开始和结束时进行错误处理的优缺点是什么 [英] What are the pros and cons of error handling at beginning vs. end of the method

问题描述

根据我的程序员的经验，我在所有可能的方式上都混合了错误处理...我创建了个人风格.

In my programmer's experience, I have mixed error handling all the ways possible... I have created my personal style.

但是，我想听听在方法的开始还是结束时，您认为错误处理的优缺点.

开始处理:

public String GenerateSomeStringData(String data, int value)
{
    if (data == null)
        throw new ArgumentNullException("data");

    if (value <= 0)
        throw new ArgumentException("value must be greater than zero");

    int dataValue;
    if (!int.TryParse(data, out dataValue))
        throw new InvalidOperationException("data does not contain an integer");

    return dataValue * 4 + value / 12;
}

最后处理:(相同的示例)

public String GenerateSomeStringData(String data, int value)
{
    if (data != null)
    {
        if (value > 0) 
        {
            int dataValue;
            if (int.TryParse(data, out dataValue))
            {
                return dataValue * 4 + value / 12;
            }
            else 
                throw new InvalidOperationException("data does not contain an integer");
        }
        else 
            throw new ArgumentException("value must be greater than zero");
    }
    else 
        throw new ArgumentNullException("data");
}

在决定如何处理此问题时，您使用什么标准?可读性，可维护性，简洁性?

What criteria do you use when deciding how to approach this? Readability, maintainability, brevity?

推荐答案

输入有效期应为前提条件执行该方法-这样，我会(并且会一直)首先首先进行错误处理.

Validity of input should be a precondition for execution of the method - as such I would (and do) always do the error handling first.

这具有以下优点:

• 对于人类而言，解析起来更容易:先验证先决条件，然后再验证执行逻辑(通常是导致某些后期情况)

• It is easier to parse for a human: validating preconditions first, then execution logic (which usually results in some post condition)

清除关注点之间的分离错误处理和执行逻辑
在您的方法中:验证逻辑未散布"在执行逻辑中

Clear separation of concerns between error handling and execution logic
within your method: validation logic is not "sprinkled in" within the execution logic

如评论中所述，您必须区分违反先决条件并触发错误条件(例如引发异常)的无效输入和构成边沿条件(即需要一些边缘条件)的有效输入特殊逻辑来处理).在确定前提条件之后，我将在方法的执行逻辑开始时分别处理后一种情况.

As mentioned in the comments you have to differentiate between invalid input that violates a precondition and triggers an error condition (such as throwing an exception) and valid input that constitutes an edge condition (i.e. requiring some special logic to handle). The later case I would handle separately after asserting the preconditions, at the beginning of the execution logic of your method.

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