清空if语句 [英] Empty if-statements

问题描述

通过空if语句，我的意思是这样的（注意分号）：

By "empty if-statement", I mean something like this (note the semicolon):

if (condition);

我在考虑应用程序时遇到了麻烦。使用while循环可以执行以下操作：

I'm having trouble thinking of an application for this. With a while loop you can do this:

while (callUntilReturnsFalse());

但是if-statement没有这样的申请。更重要的是，Java编译器在面对这样的语句时不会发出错误或警告。这可能导致大型和无声问题，特别是有一个漫长而复杂的陈述：

But there's no such application for an if-statement. What's more, the Java compiler doesn't issue an error or a warning when confronted with such a statement. This can lead to large and silent problems, especially with a long and convoluted statement:

if ((functionA() && functionB(getFoo()) ||
    checkForComplexCondition(arg1, arg2, getBar(getFoo())));
{
    doStuff();
}

我的问题是：为什么Java允许这样做？更重要的是，我可以启用一个选项，以便在发生这种情况时发出警告？

My question is: why is this allowed in Java? And, more importantly, can I enable an option to cause a warning when this happens?

（这个问题是之前询问过的关于C＃的问题，它确实发出警告，但我希望找到一种方法使用Java引发警告。）

(This question was asked before with regards to C#, which does issue a warning, but I was hoping to find a way to cause a warning with Java.)

推荐答案

为什么在Java中允许这样做？

请参阅 Java语言规范（14.6。空语句）：

空语句什么都不做。

An empty statement does nothing.

它只是被允许而且相当于（并且会被翻译为）：

It's simply allowed and it's equivalent to (and will be translated to):

if (condition) {  }

这意味着，如果条件为真，则什么都不做。

Which means, if the condition is true, do nothing.

如果你正在使用eclipse，你可以看看这里，你可能会发现一些有用的东西（我不确定分号终结符有这样的选项）：

If you're using eclipse, you can look here, you might find something useful (I'm not sure there exists such an option for semicolon terminator):

Window →首选项→ Java →编译器→错误/警告

正如@nullptr在他的回答中所指出的，存在IDE警告，你需要设置警告 on 空语句。

As @nullptr pointed out in his answer, there exist an IDE warning for this, you need to set warning on Empty statement.

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