如何在编译时验证变量 Arguments (Varargs) 的长度？

Question

I want to write a function to do replacing in string template with varargs, for example:

public static String replace (String original, String... replacements) {
    for (int i = 0; i < replacements.length; i += 2) {
        original = original.replace(replacements[i], replacements[i + 1];
    }
}

so I can call this function like:

String replaces = replace("NAME TIME", "NAME", "Abc", "TIME", "20:12");

Apparently, replacements.length should be a multiple of 2 and I want to validate this at compile time, I want to achieve something like:

@ValidateVarargs("length % 2 == 0", "replacements.length must be a multiple of 2")
public static String replace (String original, String... replacements) {
    for (int i = 0; i < replacements.length; i += 2) {
        original = original.replace(replacements[i], replacements[i + 1];
    }
}

And when I call this function with odd number of replacement strings, It will give me some compilation errors like:

Compilation error: replacements.length must be a multiple of 2
At path/to/Xxx.java line yyy (where this function was called)

Is it possible? If possible, how to do it?

Or, if this can not be achieved by using Annotations, is there any IDE or IDE plugin or some other thing can do this validation before or during compiling?

Thanks.

Answer 1

I would suggest to redesign your api. Having method invocations with multiple string arguments in a row makes it difficult to tell which is the string being replaced and the replacement.

I would think of something like that:

StringReplacement.builder()
    .replace("being replaced", "replacement")
    .replace("yet another", "replacement")
    .build()
    .replace(stringToRunReplacementsOn);