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 +1,107 @@
+import java.io.IOException;
+import java.nio.file.FileSystems;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.StandardCopyOption;
+import java.nio.file.StandardWatchEventKinds;
+import java.time.Instant;
+import java.util.Arrays;
+import java.util.UUID;
+import java.util.function.Consumer;
+
+final class FileMessageBoard {
+    static final Path ROOT = Path.of(
+        System.getProperty("messageBoard.root", "messageBoard")
+    ).toAbsolutePath().normalize();
+
+    private FileMessageBoard() {}
+
+    static String serialize(Message message) {
+        var text = message.type() + "\n" + message.value();
+
+        if (message.timestamp() != null)
+            text += "\nTIMESTAMP: " + message.timestamp();
+
+        return text;
+    }
+
+    static Message read(Path file) throws IOException {
+        var lines = Files.readString(file).split("\\R", -1);
+
+        if (lines.length < 2)
+            throw new IOException("A message needs a type and a value: " + file);
+
+        var endOfValue = lines.length;
+        Instant timestamp = null;
+        var lastLine = lines[lines.length - 1];
+
+        if (lastLine.startsWith("TIMESTAMP: ")) {
+            timestamp = Instant.parse(lastLine.substring("TIMESTAMP: ".length()));
+            endOfValue--;
+        }
+
+        var value = String.join(
+            "\n",
+            Arrays.copyOfRange(lines, 1, endOfValue)
+        );
+
+        return new Message(lines[0], value, timestamp);
+    }
+
+    static void publish(String mailbox, Message message) throws IOException {
+        publishText(mailbox, serialize(message));
+    }
+
+    static void publishText(String mailbox, String content) throws IOException {
+        var directory = directory(mailbox);
+        Files.createDirectories(directory);
+
+        var id = UUID.randomUUID().toString();
+        var temporary = directory.resolve(id + ".tmp");
+        var published = directory.resolve(id + ".msg");
+
+        Files.writeString(temporary, content);
+        Files.move(temporary, published, StandardCopyOption.ATOMIC_MOVE);
+    }
+
+    static void watch(String mailbox, Consumer<Message> receiver)
+            throws IOException, InterruptedException {
+        var directory = directory(mailbox);
+        Files.createDirectories(directory);
+
+        try (var watcher = FileSystems.getDefault().newWatchService()) {
+            directory.register(watcher, StandardWatchEventKinds.ENTRY_CREATE);
+
+            while (true) {
+                var key = watcher.take();
+
+                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))
+                        receiver.accept(read(file));
+                }
+
+                if (!key.reset())
+                    return;
+            }
+        }
+    }
+
+    static Path directory(String name) {
+        var directory = ROOT.resolve(name).normalize();
+
+        if (!directory.startsWith(ROOT))
+            throw new IllegalArgumentException("Mailbox escapes the message board");
+
+        return directory;
+    }
+}