Use of FilenameFilter

Question

I have a directory:

File dir = new File(MY_PATH);

I would like to list all the files whose name is indicated as integer numbers strings, e.

Answer 1

You should override accept in the interface FilenameFilter and make sure that the parameter name has only numeric chars. You can check this by using matches:

String[] list = dir.list(new FilenameFilter() {
    @Override
    public boolean accept(File dir, String name) {
        return name.matches("[0-9]+");
    }
});