How to implement a method to return Iterator of files recursively in Java

Question

I want to implement a method like this:

public Iterator<File> getFiles(String root) {
  // return an Iterator looping through all files in root and all files in sub-directories of roots (recursively)
}

In C#, this can easily be implemented with the yield return keyword. In Java, I suspect I have to end up writing a lot of complicated code to get it done. Is there any good solution to this problem?

Edit: I want the returned Iterator to be "lazy", i.e. only return a new File when next() is invoked. (That is the behavior C#'s yield return offers.)

Answer 1

Apache Commons FileUtils offers iterator methods to iterate through directories and subdirectories. That does what you want and should save you a lot of work.

e.g.

Iterator fi = iterateFiles(new File("."), String[] {".csv"}, true)

to find all .csv files below the current directory.

Answer 2

This code might be your solution http://snippets.dzone.com/posts/show/3532

Answer 3

I might have missed something, but why don't you just make your own iterator class which implements iterator. Then you just need to implement a lazy next() method in you iterator.