added scheduler

src/main/java/com/commafeed/backend/task/OrphansCleanupTask.java

@@ -0,0 +1,47 @@
+package com.commafeed.backend.task;
+
+import java.util.concurrent.TimeUnit;
+
+import lombok.RequiredArgsConstructor;
+
+import org.hibernate.SessionFactory;
+
+import com.commafeed.backend.dao.UnitOfWork;
+import com.commafeed.backend.service.DatabaseCleaningService;
+import com.commafeed.backend.task.SchedulingService.ScheduledTask;
+
+@RequiredArgsConstructor
+public class OrphansCleanupTask implements ScheduledTask {
+
+	private final SessionFactory sessionFactory;
+	private final DatabaseCleaningService cleaner;
+
+	@Override
+	public void run() {
+		new UnitOfWork<Void>(sessionFactory) {
+			@Override
+			protected Void runInSession() throws Exception {
+				cleaner.cleanEntriesWithoutSubscriptions();
+				cleaner.cleanFeedsWithoutSubscriptions();
+				cleaner.cleanContentsWithoutEntries();
+				return null;
+			}
+		}.run();
+	}
+
+	@Override
+	public long getInitialDelay() {
+		return 30;
+	}
+
+	@Override
+	public long getPeriod() {
+		return 60;
+	}
+
+	@Override
+	public TimeUnit getTimeUnit() {
+		return TimeUnit.MINUTES;
+	}
+
+}