Implement static inner interface as anonymous class in Scala

Question

I'd like to use NIO.2 features with Scala (classes are in java.nio.file):

In Java I would do:

Files.newDirectoryStream(Paths.get("/tmp"), new DirectoryStream.Filter<Path>() {
  @Override
  public boolean accept(Path entry) throws IOException {
    return false;
  }
});

How can I do same in Scala? The Fitler is static interface insideDirectoryStream interface.

Thank you.

EDIT: Please do not reply if you want to suggest me another library/method for listing files. I'm mainly interested in the main problem.

oxbow_lakes · Accepted Answer · 2012-03-02 14:09:22Z

5

Not 100% sure whether you are asking for a literal conversion of this code in scala:

Files.newDirectoryStream(Paths.get("/tmp"), new DirectoryStream.Filter[Path] {
  def accept(entry: Path) = false
})

..or something else? You could add an implicit conversion:

class PathPredicateFilter(p: Path => Boolean) 
  extends DirectoryStream.Filter[Path] {
  def accept(entry: Path) = p(entry)
}
implicit def PathPredicate_Is_DirectoryStreamFilter(p: Path => Boolean) 
  = new PathPredicateFilter(p)

Now you can do this:

Files.newDirectoryStream(Paths.get("/tmp"), (p: Path) => false /* your code here */)

edited Mar 2, 2012 at 14:09

answered Mar 2, 2012 at 14:04

oxbow_lakes

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1 Comment

woky Over a year ago

Damnit. Yes I wanted literal conversion because I think I've tried every possible syntax combination and googled very hard. Thank you very much.

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