By the way, what's your import and/or dynamic import header ?
Your error seems related to a missing import in your bundle.
Regards
JB
On Tue, Jan 28, 2025 at 9:52 PM Matthias Wegner
<matthias.weg...@email.de> wrote:
>
> Hi All,
>
> I try since hours to build a Thread-Safe OSGi Service which watches a
> directory for file changes and executes on modification. See description
> bellow. Can someone give me a tip a working example for a thread safe service?
>
> Regards, Matthias
>
>
> PROBLEM
>
> The problem is, that I get not the Thread correctly registered. I have
> already successfully registered some services in activator and bundle
> Context. But somehow I did not get this started on the DirectoryWatcher. And
> in different experiments and when the execution starts, then I get the
> following erros:
>
> ERROR ON EXCECUTION
> Exception in thread
>
> java.lang.NoClassDefFoundError: org/rogatio/k3/base/service/WorkitemService
>
> at
> org.rogatio.k3.base.service.DirectoryWatcher.run(RecursiveDirectoryWatcher.java:91)
>
> at java.base/java.lang.Thread.run(Thread.java:829)
>
> ...
>
> Caused by: java.lang.ClassNotFoundException: Unable to load class
> 'com.fasterxml.jackson.databind.ObjectMapper' because the bundle wiring for
> org.rogatio.k3-base-core is no longer valid.
>
>
> ERROR ON INSTALLING BUNDLE
>
> Error executing command: Unable to resolve root: missing requirement [root]
> osgi.identity; osgi.identity=k3-base; type=karaf.feature;
> version="[1.0.0.SNAPSHOT,1.0.0.SNAPSHOT]";
> filter:="(&(osgi.identity=k3-base)(type=karaf.feature)(version>=1.0.0.SNAPSHOT)(version<=1.0.0.SNAPSHOT))"
> [caused by: Unable to resolve k3-base/1.0.0.SNAPSHOT: missing requirement
> [k3-base/1.0.0.SNAPSHOT] osgi.identity;
> osgi.identity=org.rogatio.k3-base-core; type=osgi.bundle;
> version="[1.0.0.SNAPSHOT,1.0.0.SNAPSHOT]"; resolution:=mandatory [caused by:
> Unable to resolve org.rogatio.k3-base-core/1.0.0.SNAPSHOT: missing
> requirement [org.rogatio.k3-base-core/1.0.0.SNAPSHOT] osgi.service;
> filter:="(objectClass=org.rogatio.k3.base.service.RecursiveDirectoryWatcher)";
> effective:=active]]
>
>
>
> CODE
> ----------------------------------------------------------------------------
> import java.io.IOException;
> import java.nio.file.*;
> import java.nio.file.attribute.BasicFileAttributes;
> import java.util.HashMap;
> import java.util.Map;
>
> public class RecursiveDirectoryWatcher implements Runnable {
> private final Path rootDir;
> private final WatchService watchService;
> private final Map<WatchKey, Path> keyToPathMap;
>
> public RecursiveDirectoryWatcher(String rootDir) throws IOException {
> this.rootDir = Paths.get(rootDir);
> this.watchService = FileSystems.getDefault().newWatchService();
> this.keyToPathMap = new HashMap<>();
> registerAll(this.rootDir); // Register all subdirectories
> }
>
> // Register a directory and all its subdirectories
> private void registerAll(final Path start) throws IOException {
> Files.walkFileTree(start, new SimpleFileVisitor<>() {
> @Override
> public FileVisitResult preVisitDirectory(Path dir,
> BasicFileAttributes attrs) throws IOException {
> registerDirectory(dir);
> return FileVisitResult.CONTINUE;
> }
> });
> }
>
> // Register a single directory with the WatchService
> private void registerDirectory(Path dir) throws IOException {
> WatchKey key = dir.register(
> watchService,
> StandardWatchEventKinds.ENTRY_CREATE,
> StandardWatchEventKinds.ENTRY_MODIFY,
> StandardWatchEventKinds.ENTRY_DELETE
> );
> keyToPathMap.put(key, dir);
> System.out.println("Watching directory: " + dir);
> }
>
> @Override
> public void run() {
> System.out.println("Starting to watch directory: " + rootDir);
> while (true) {
> WatchKey key;
> try {
> key = watchService.take(); // Wait for events
> } catch (InterruptedException e) {
> Thread.currentThread().interrupt();
> System.out.println("Directory watching interrupted.");
> break;
> }
>
> Path dir = keyToPathMap.get(key);
> if (dir == null) {
> System.err.println("WatchKey not recognized!");
> continue;
> }
>
> for (WatchEvent<?> event : key.pollEvents()) {
> WatchEvent.Kind<?> kind = event.kind();
>
> // Resolve the relative file name to an absolute path
> Path name = (Path) event.context();
> Path fullPath = dir.resolve(name);
>
> System.out.println("Event: " + kind + " on file: " +
> fullPath);
>
> // EXECUTE HERE THE CODE OF AN OSGI-BUNDLE which parses JSON-Files
>
> // If a new directory is created, register it
> if (kind == StandardWatchEventKinds.ENTRY_CREATE) {
> try {
> if (Files.isDirectory(fullPath)) {
> registerAll(fullPath);
> }
> } catch (IOException e) {
> System.err.println("Failed to register directory: " +
> fullPath);
> }
> }
> }
>
> // Reset the key to continue watching
> boolean valid = key.reset();
> if (!valid) {
> keyToPathMap.remove(key);
> if (keyToPathMap.isEmpty()) {
> System.out.println("All directories are no longer valid.
> Stopping.");
> break;
> }
> }
> }
> }
>
> public static void main(String[] args) {
> String directoryToWatch = "/path/to/root/directory";
>
> try {
> // Create a new thread for the directory watcher
> Thread watcherThread = new Thread(new
> RecursiveDirectoryWatcher(directoryToWatch));
> watcherThread.start();
>
> // Main thread can do other tasks while the watcher thread runs
> System.out.println("Main thread is free to do other tasks...");
> } catch (IOException e) {
> e.printStackTrace();
> }
> }
> }
>
>
