Search for all po files in a directory and its subdirectories and create a Hashmap containing the filepaths as value and its directory as key

Question

I want to search for all .po files in a directory and add them to a HashMap.

My directories looks like the following:

dir1\<any number of subdirs>\*_en_*.po
                             *_it_*.po
                             ...
dir2\<any number of subdirs>\*_en_*.po
.                            *_es_*.po
.                            ...
.
dirn\<any number of subdirs>\...

How can I represent/search these files with the help of java-Streams and HashMap<String, List<File>>, with en/de/it.po as a List<File> type and the respective directory root of these files dir1\subdir-1\**\subdir-n as a key?

I've tried the following solution from a similar post: https://stackoverflow.com/a/62824848/10042081 but I wasn't able to manipulate the filter/groupings correctly in order to solve my problem.
I've also tried to use listFiles() + isDirectory() recursively in order to achieve the desired result, with no success.

You may want to show your attempt code, and tell the details about the problems that you are having with it — Hovercraft Full Of Eels, Jul 24 '22 at 22:24
Thanks for your answer. I've used the mentioned solution in the other post and tried to add/replace the filter with `.filter(p -> p.toString().endsWith("po")` which didn't work, because nested directories were not included. I didn't knew what I needed to change in order to get the desired result. — Doesbaddel, Jul 25 '22 at 06:42

score 2 · Accepted Answer · answered Jul 25 '22 at 06:16

This is pretty simple using Files.find() to walk a directory tree looking for matching files, and Collectors.groupingBy() to convert that stream into the desired map.

import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.util.List;
import java.util.Map;
import java.util.stream.Collectors;

public class Demo {
    public static void main(String[] args) {
        for (String dir : args) {
            try (var files = Files.find(Path.of(dir), 256,
                                        (p, attr) -> p.getFileName().toString().endsWith(".po"))) {
                Map<String, List<Path>> po_files =
                    files.collect(Collectors.groupingBy(p -> p.getParent().toString()));
                System.out.println(po_files);
            } catch (IOException e) {
                System.err.println(e);
                System.exit(1);
            }
        }
    }
}

This will give you a map where the keys are paths to directories, and the values are lists of paths to all the .po files in those directories.

Search for all po files in a directory and its subdirectories and create a Hashmap containing the filepaths as value and its directory as key

1 Answers1