Extract Periodic class from connection's Worker

client/src/connection.vala

@@ -84,29 +84,18 @@ namespace StudySystemClient {
 		}
 	}
 
-	private class Worker {
-		private uint TASK_PERIOD_MS = 10;
+	private class Worker : Periodic {
+		private const uint TASK_PERIOD_MS = 10;
 
 		private SessionManager session_manager;
-		private bool exit;
-		private Thread<void> thread;
 
 		public Worker(SessionManager session_manager) {
+			base(TASK_PERIOD_MS);
 			this.session_manager = session_manager;
-			exit = false;
-			thread = new Thread<void>("connection_worker", body);
 		}
 
-		~Worker() {
-			exit = true;
-			thread.join();
-		}
-
-		private void body() {
-			while (!exit) {
+		protected override void task() {
 			session_manager.task();
-				Thread.usleep(1000 * TASK_PERIOD_MS);
-			}
 		}
 	}
 }

client/src/meson.build

@@ -17,6 +17,7 @@ lib = library(
     'connection.vala',
     'der.vala',
     'main_window.vala',
+    'periodic.vala',
     'request.vala',
     'response.vala',
     'session_manager.vala',

client/src/periodic.vala

@@ -0,0 +1,27 @@
+namespace StudySystemClient {
+	public abstract class Periodic {
+		private uint period_ms;
+		private bool exit;
+		private Thread<void> thread;
+
+		protected Periodic(uint period_ms) {
+			this.period_ms = period_ms;
+			exit = false;
+			thread = new Thread<void>("Periodic task", body);
+		}
+
+		~Periodic() {
+			exit = true;
+			thread.join();
+		}
+
+		protected abstract void task();
+
+		private void body() {
+			while (!exit) {
+				task();
+				Thread.usleep(1000 * period_ms);
+			}
+		}
+	}
+}