use dropwizard built-in executor service facilities

src/main/java/com/commafeed/CommaFeedApplication.java

@@ -11,6 +11,7 @@ import io.dropwizard.setup.Environment;
 
 import java.util.Date;
 import java.util.EnumSet;
+import java.util.concurrent.ScheduledExecutorService;
 
 import javax.servlet.DispatcherType;
 
@@ -34,7 +35,6 @@ import com.commafeed.backend.service.StartupService;
 import com.commafeed.backend.service.UserService;
 import com.commafeed.backend.task.OldStatusesCleanupTask;
 import com.commafeed.backend.task.OrphansCleanupTask;
-import com.commafeed.backend.task.SchedulingService;
 import com.commafeed.frontend.auth.SecurityCheckProvider;
 import com.commafeed.frontend.auth.SecurityCheckProvider.SecurityCheckUserServiceProvider;
 import com.commafeed.frontend.resource.AdminREST;
@@ -127,10 +127,9 @@ public class CommaFeedApplication extends Application<CommaFeedConfiguration> {
 		environment.servlets().addServlet("analytics.js", injector.getInstance(AnalyticsServlet.class)).addMapping("/analytics.js");
 
 		// Scheduled tasks
-		SchedulingService schedulingService = new SchedulingService();
-		schedulingService.register(injector.getInstance(OldStatusesCleanupTask.class));
-		schedulingService.register(injector.getInstance(OrphansCleanupTask.class));
-		environment.lifecycle().manage(schedulingService);
+		ScheduledExecutorService executor = environment.lifecycle().scheduledExecutorService("task-scheduler").build();
+		injector.getInstance(OldStatusesCleanupTask.class).register(executor);
+		injector.getInstance(OrphansCleanupTask.class).register(executor);
 
 		// database init/changelogs
 		environment.lifecycle().manage(injector.getInstance(StartupService.class));

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

@@ -10,11 +10,10 @@ import lombok.RequiredArgsConstructor;
 
 import com.commafeed.CommaFeedConfiguration;
 import com.commafeed.backend.service.DatabaseCleaningService;
-import com.commafeed.backend.task.SchedulingService.ScheduledTask;
 
 @RequiredArgsConstructor(onConstructor = @__({ @Inject }))
 @Singleton
-public class OldStatusesCleanupTask implements ScheduledTask {
+public class OldStatusesCleanupTask extends ScheduledTask {
 
 	private final CommaFeedConfiguration config;
 	private final DatabaseCleaningService cleaner;

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

@@ -8,11 +8,10 @@ import javax.inject.Singleton;
 import lombok.RequiredArgsConstructor;
 
 import com.commafeed.backend.service.DatabaseCleaningService;
-import com.commafeed.backend.task.SchedulingService.ScheduledTask;
 
 @RequiredArgsConstructor(onConstructor = @__({ @Inject }))
 @Singleton
-public class OrphansCleanupTask implements ScheduledTask {
+public class OrphansCleanupTask extends ScheduledTask {
 
 	private final DatabaseCleaningService cleaner;
 

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

@@ -0,0 +1,32 @@
+package com.commafeed.backend.task;
+
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.TimeUnit;
+
+import lombok.extern.slf4j.Slf4j;
+
+@Slf4j
+public abstract class ScheduledTask {
+	protected abstract void run();
+
+	protected abstract long getInitialDelay();
+
+	protected abstract long getPeriod();
+
+	protected abstract TimeUnit getTimeUnit();
+
+	public void register(ScheduledExecutorService executor) {
+		Runnable runnable = new Runnable() {
+			@Override
+			public void run() {
+				try {
+					ScheduledTask.this.run();
+				} catch (Exception e) {
+					log.error(e.getMessage(), e);
+				}
+			}
+		};
+		executor.scheduleWithFixedDelay(runnable, getInitialDelay(), getPeriod(), getTimeUnit());
+	}
+
+}

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

@@ -1,56 +0,0 @@
-package com.commafeed.backend.task;
-
-import io.dropwizard.lifecycle.Managed;
-
-import java.util.List;
-import java.util.concurrent.Executors;
-import java.util.concurrent.ScheduledExecutorService;
-import java.util.concurrent.TimeUnit;
-
-import lombok.extern.slf4j.Slf4j;
-
-import com.google.common.collect.Lists;
-
-@Slf4j
-public class SchedulingService implements Managed {
-
-	public static interface ScheduledTask {
-		void run();
-
-		long getInitialDelay();
-
-		long getPeriod();
-
-		TimeUnit getTimeUnit();
-	}
-
-	private List<ScheduledTask> tasks = Lists.newArrayList();
-	private ScheduledExecutorService executor;
-
-	@Override
-	public void start() throws Exception {
-		executor = Executors.newScheduledThreadPool(tasks.size());
-		for (final ScheduledTask task : tasks) {
-			Runnable runnable = new Runnable() {
-				@Override
-				public void run() {
-					try {
-						task.run();
-					} catch (Exception e) {
-						log.error(e.getMessage(), e);
-					}
-				}
-			};
-			executor.scheduleWithFixedDelay(runnable, task.getInitialDelay(), task.getPeriod(), task.getTimeUnit());
-		}
-	}
-
-	@Override
-	public void stop() throws Exception {
-		executor.shutdown();
-	}
-
-	public void register(ScheduledTask task) {
-		tasks.add(task);
-	}
-}