CODEWITHSUNDEEP
javanio
Black
Black

Reputation: 5367

java nio Files.find to count subdirectories

I was expecting this code using Java 8's Files#find method from a java.nio.File to return a count of all the sub directories of the current directory:

public static void main(String[] args) throws IOException {
    List<File> dirs = new LinkedList<File>();
    Files.find(Paths.get("."),
               Integer.MAX_VALUE,
               (path, basicFileAttributes) -> dirs.add(path.toFile()));
    System.out.println(dirs.size());
}

however, it always outputs 0. Where is my misunderstanding?

Upvotes: 0

Views: 509

Answers (3)

NishanthSpShetty
NishanthSpShetty

Reputation: 659

Files.find returns stream, which you haven't consumed hence the lambda you passed to add files to dirs not executed. stream should be consumed, try the following

`

public static void main(String[] args) throws IOException {

      List<File> dirs = new LinkedList<File>();
      Files.find(Paths.get("."),
             Integer.MAX_VALUE,
            (path, basicFileAttributes) -> 
      dirs.add(path.toFile())).forEach((ignore)->{});

     java.lang.System.out.println( dirs.size() );
}

Upvotes: 1

Bal&#225;zs N&#233;meth
Bal&#225;zs N&#233;meth

Reputation: 6637

Have a look at the docs of Files#find: the third param is a function used to decide whether a file should be included in the returned stream. You're not adding anything to the dirs list.

Try this where the matcher function filters for directories:

    List<Path> found = Files.find(start,
            Integer.MAX_VALUE,
            (path, basicFileAttributes) -> path.toFile().isDirectory()).collect(Collectors.toList());

    java.lang.System.out.println(found.size());

Upvotes: 1

achAmh&#225;in
achAmh&#225;in

Reputation: 4266

You could use File.isDirectory() to count them:

static int countSub(File[] directory) {
    int total = 0;
    for (File files : directory) {
        if (files.isDirectory()) {
            total++;
        }
    }
    return total;
}

Upvotes: -1

Related Questions