smarter way of getting the next feed to update

src/main/java/com/commafeed/backend/feeds/FeedRefreshTaskGiver.java

@@ -0,0 +1,33 @@
+package com.commafeed.backend.feeds;
+
+import java.util.List;
+import java.util.Queue;
+
+import javax.ejb.Lock;
+import javax.ejb.LockType;
+import javax.ejb.Singleton;
+import javax.inject.Inject;
+
+import com.commafeed.backend.dao.FeedDAO;
+import com.commafeed.backend.model.Feed;
+import com.google.common.collect.Lists;
+
+@Singleton
+public class FeedRefreshTaskGiver {
+
+	@Inject
+	FeedDAO feedDAO;
+
+	private Queue<Feed> queue = Lists.newLinkedList();
+
+	@Lock(LockType.WRITE)
+	public Feed take() {
+		if (queue.peek() == null) {
+			List<Feed> feeds = feedDAO.findNextUpdatable(30);
+			for (Feed feed : feeds) {
+				queue.add(feed);
+			}
+		}
+		return queue.poll();
+	}
+}

src/main/java/com/commafeed/backend/feeds/FeedRefreshWorker.java

@@ -48,6 +48,9 @@ public class FeedRefreshWorker {
 	@Inject
 	FeedUpdateService feedUpdateService;
 
+	@Inject
+	FeedRefreshTaskGiver taskGiver;
+
 	@Resource
 	private UserTransaction transaction;
 
@@ -117,22 +120,7 @@ public class FeedRefreshWorker {
 
 	}
 
-	private Feed getNextFeed() throws NotSupportedException, SystemException,
-			SecurityException, IllegalStateException, RollbackException,
-			HeuristicMixedException, HeuristicRollbackException {
-
-		Feed feed = null;
-		lock.lock();
-		try {
-			feed = Iterables.getFirst(feedDAO.findNextUpdatable(1), null);
-			if (feed != null) {
-				feed.setLastUpdated(Calendar.getInstance().getTime());
-				feedDAO.update(feed);
-			}
-		} finally {
-			lock.unlock();
-		}
-
-		return feed;
+	private Feed getNextFeed() {
+		return taskGiver.take();
 	}
 }