CODEWITHSUNDEEP
javajava-io
Mohd Naved
Mohd Naved

Reputation: 458

myFile.isFile() or myFile.isDirectory() is there any third type of function possible?

I was writing a common function to check if the variable contains a file or a directory. So I came up with an idea to check it using a boolean return-type function. something like this : 

function boolean checkFileOrDirectory(File myFile){
    // Assume file already exist
    if(myFile.isDirectory()){
        //myFile is a directory
        return true;
    } else {
        //myFile is a file
        return false;
    }
}

I was wondering about the accuracy of this function. I would really appreciate if anyone can tell me will there be any kind of file types which does not come under both isFile() or isDirectory() ?

Upvotes: 3

Views: 1041

Answers (1)

Andy Turner
Andy Turner

Reputation: 140514

The "file" could be something like a symlink. Whether or not the distinction between a file and a symlink to a file is important depends upon your application.

Using boolean to represent "is something or something else" is a bad idea, because it's not clear what "true" or "false" mean.

Even if you remember that "true" means "is a directory", "false" logically means "is not a directory"... And so the reader is left wondering "well, I know it's not a directory, but what is it?"

And the very fact you are asking the question demonstrates this.

Consider using an enum instead:

enum Kind { DIRECTORY, FILE }

Not only is this self-documenting (you will have code saying something like "if this is a file/else if this is a directory"), it leaves the possibility of adding additional types in the future.

Upvotes: 2

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