Add SIN.04028 tutorial material, tutor prompt and conversation log

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
2026-09-15 15:11:02 +02:00
parent bac80295b7
commit f615bef426
30 changed files with 8123 additions and 0 deletions
@@ -0,0 +1,106 @@
+import java.io.IOException;
+import java.io.UncheckedIOException;
+import java.nio.file.ClosedWatchServiceException;
+import java.nio.file.FileSystems;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.StandardWatchEventKinds;
+import java.nio.file.WatchKey;
+import java.nio.file.WatchService;
+import java.util.Map;
+import java.util.concurrent.BlockingQueue;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.LinkedBlockingQueue;
+
+record IncomingMessage(String mailbox, Message message) {}
+
+final class FileSubscriptions implements AutoCloseable {
+    private final WatchService watcher;
+    private final Map<String, WatchKey> subscriptions = new ConcurrentHashMap<>();
+    private final Map<WatchKey, String> mailboxes = new ConcurrentHashMap<>();
+    private final BlockingQueue<IncomingMessage> messages =
+        new LinkedBlockingQueue<>();
+    private final Thread observer;
+
+    FileSubscriptions() throws IOException {
+        watcher = FileSystems.getDefault().newWatchService();
+        observer = Thread.ofVirtual().start(this::observe);
+    }
+
+    void subscribe(String mailbox) throws IOException {
+        if (subscriptions.containsKey(mailbox))
+            return;
+
+        var directory = FileMessageBoard.directory(mailbox);
+        Files.createDirectories(directory);
+        var key = directory.register(
+            watcher,
+            StandardWatchEventKinds.ENTRY_CREATE
+        );
+
+        subscriptions.put(mailbox, key);
+        mailboxes.put(key, mailbox);
+    }
+
+    void unsubscribe(String mailbox) {
+        var key = subscriptions.remove(mailbox);
+
+        if (key != null) {
+            mailboxes.remove(key);
+            key.cancel();
+        }
+    }
+
+    IncomingMessage take() throws InterruptedException {
+        return messages.take();
+    }
+
+    private void observe() {
+        try {
+            while (true) {
+                var key = watcher.take();
+                var mailbox = mailboxes.get(key);
+
+                if (mailbox == null) {
+                    key.reset();
+                    continue;
+                }
+
+                var directory = FileMessageBoard.directory(mailbox);
+
+                for (var event : key.pollEvents()) {
+                    if (event.kind() == StandardWatchEventKinds.OVERFLOW)
+                        continue;
+
+                    var filename = (Path) event.context();
+
+                    if (!filename.toString().endsWith(".msg"))
+                        continue;
+
+                    var file = directory.resolve(filename);
+
+                    if (Files.isRegularFile(file))
+                        messages.put(
+                            new IncomingMessage(mailbox, FileMessageBoard.read(file))
+                        );
+                }
+
+                if (!key.reset()) {
+                    subscriptions.remove(mailbox);
+                    mailboxes.remove(key);
+                }
+            }
+        } catch (ClosedWatchServiceException _) {
+            // close() ends the observer.
+        } catch (InterruptedException _) {
+            Thread.currentThread().interrupt();
+        } catch (IOException exception) {
+            throw new UncheckedIOException(exception);
+        }
+    }
+
+    public void close() throws IOException {
+        watcher.close();
+        observer.interrupt();
+    }
+}