为什么不抛出异常，如果[super init]返回nil？ [英] Why not throw an exception if [super init] returns nil?

问题描述

这被认为是典型的

- (id)init {
    self = [super init];
    if (self) {
        // <#initializations#>
    }
    return self;
}

但是最好不要这样做

- (id)init {
    self = [super init];
    if (self) {
        // <#initializations#>
    } else {
       @throw [NSException exceptionWithName:NSInternalInconsistencyException reason:@"you think your constructor is executing, but it's not"] userInfo:nil]
    }
    return self;
}

这个问题的推论是under什么条件会 [super init] return nil 和 $ c> init 方法？

The corollary to this question is, "under what conditions would [super init] return nil and shouldn't you handle that in the init method?"

推荐答案

，JustSid的意思是：

One reason, why you should do, what JustSid is saying:

在面向对象的设计中，你应该总是编写代码，好像你可能会把你的类交给另一个开发者的另一个项目。所以你不能假设，他的项目中的初始化失败可能是坏的，因为它可能在你的。也许这个开发者是你在5年。想象一下你的麻烦来修复你的200个类，你想重用。

In object-orientated design you should always code, as if you maybe will hand your class over to another project by another developer. So you can't assume, that a failure in initialization in his project may be as bad as it is probably in yours. Maybe this developer is you in 5 years. Imagine your hassle to fix your 200 classes, you want to reuse.

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