ability to subscribe to a feed

src/main/java/com/commafeed/backend/dao/FeedService.java

@@ -1,10 +1,18 @@
 package com.commafeed.backend.dao;
 
+import java.util.List;
+
 import javax.ejb.Stateless;
 
 import com.commafeed.backend.model.Feed;
+import com.commafeed.frontend.utils.ModelFactory.MF;
+import com.google.common.collect.Iterables;
 
 @Stateless
 public class FeedService extends GenericDAO<Feed, Long> {
 
+	public Feed findByUrl(String url) {
+		List<Feed> feeds = findByField(MF.i(proxy().getUrl()), url);
+		return Iterables.getFirst(feeds, null);
+	}
 }

src/main/java/com/commafeed/backend/dao/GenericDAO.java

@@ -56,7 +56,7 @@ public abstract class GenericDAO<T, K> implements
 		em.remove(object);
 	}
 
-	public void deleteById(Object id) {
+	public void deleteById(K id) {
 		Object ref = em.getReference(getType(), id);
 		em.remove(ref);
 	}