Which is better - using String or File as parameter type for methods that take filenames [closed]

Answer 1

If you pass the string, you have control in the method over how the file is opened, and the file handle managed. You are centralising that code. If you pass the File object, then you are duplicating the file handling code everywhere this is called. So I'd have a strong preference for the former.

Answer 2

I would pass an java.io.InputStream - this makes the code easier to test and doesn't bind it to the file system.

This way your code ends up like:

public void normalizeData(InputStream in)
{
  ...
}

And calling it:

myObject.normalizeData(new FileInputStream(myFile));

Or

myObject.normalizeData(new FileInputStream("c:/myfile.txt"));

Or in a test

myObject.normalizeData(new ByteArrayInputStream("some test data".getBytes()));

Answer 3

Think about using multiple overloaded methods to give the user of the API the choose.

Also think about passing an InputStream as it is possible that the user of the API wants to use any in memory representation of the data.

Answer 4

It depends whether you want the file hanlde outside the normalizeData method or inside it only. If you want to do something on file prior or after calling your normalizeData method then create a file object outside normalizeData method and pass the reference to the method. If ONLY your normalizeData method need to work on the file object then simply pass the filename to it.

Depends on your need and how you want to handle your file.

Answer 5

The design depends on many parameters, such as, who is going to use this method. Is it going to be overloaded, is it internal, package level or public API. I would tend to be general and offer two overloaded methods:

• one which passes in the Path which is a common way of specifying the path to a file

• and one which passes in the InputStream, i.e. general representation of input stream of bytes

  public void normalizeData(Path filePath) //Path is a common way for specifying file path

  public void normalizeData(InputStream) //general representation of input stream of bytes

But as I said, it depends on your project specification.