Java：将预定长度的数组设置为方法参数？

Question

I have a method that takes 5 double values and performs an action with them. Right now the argument list is five different doubles. Is there any way to pass a double[] as an argument to the method but make sure its length is exactly 5?

One way is this:

private void myMethod(double[] args) {
    if (args.length == 5) {
        // do something
    }
}

but is there a better way?

Answer 1

If you know you need exactly 5 doubles, then I think you are better off asking for 5 distinct doubles. Having them listed out with meaningful names it will still be hard enough (even with intellisense or whatever it's called) to keep the order of the variables straight. If they are in an array, the user will need to consult the documentation to see which value should go in which index.

Answer 2

No. You can't restrict the length of an array passed to a function.

If your goal is to keep the checking code out of the method so it's cleaner, you could delegate the real work to another method.

If your concern is the length of the parameter list you could pass a parameter object.

Answer 3

You could create a class which is a specialization of a Vector limited to 5 doubles, but it seems like overkill. I would just throw an exception if there are too few or too many entries in the array - this is likely a programming problem rather than a runtime exception.

Answer 4

You could put your code in try-catch block. This provides to miss an unnecessary check. But if something doing wrong you could avoid the problems with exception.