method to merge feeds

src/main/java/com/commafeed/backend/model/Feed.java

@@ -4,7 +4,6 @@ import java.util.Date;
 import java.util.Set;
 
 import javax.persistence.Cacheable;
-import javax.persistence.CascadeType;
 import javax.persistence.Column;
 import javax.persistence.Entity;
 import javax.persistence.ManyToMany;
@@ -111,7 +110,7 @@ public class Feed extends AbstractModel {
 	@Column(length = 40)
 	private String lastContentHash;
 
-	@ManyToMany(mappedBy = "feeds", cascade = CascadeType.REMOVE)
+	@ManyToMany(mappedBy = "feeds")
 	private Set<FeedEntry> entries = Sets.newHashSet();
 
 	@OneToMany(mappedBy = "feed")

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

@@ -1,5 +1,7 @@
 package com.commafeed.backend.services;
 
+import java.util.List;
+
 import javax.ejb.Lock;
 import javax.ejb.LockType;
 import javax.ejb.Singleton;
@@ -8,8 +10,10 @@ import javax.inject.Inject;
 import org.apache.commons.codec.digest.DigestUtils;
 
 import com.commafeed.backend.dao.FeedDAO;
+import com.commafeed.backend.dao.FeedSubscriptionDAO;
 import com.commafeed.backend.feeds.FeedUtils;
 import com.commafeed.backend.model.Feed;
+import com.commafeed.backend.model.FeedSubscription;
 
 @Singleton
 public class FeedService {
@@ -17,6 +21,9 @@ public class FeedService {
 	@Inject
 	FeedDAO feedDAO;
 
+	@Inject
+	FeedSubscriptionDAO feedSubscriptionDAO;
+
 	@Lock(LockType.WRITE)
 	public Feed findOrCreate(String url) {
 		Feed feed = feedDAO.findByUrl(url);
@@ -32,4 +39,19 @@ public class FeedService {
 		return feed;
 	}
 
+	public void mergeFeeds(Feed into, Feed... feeds) {
+		for (Feed feed : feeds) {
+			if (into.getId().equals(feed.getId())) {
+				continue;
+			}
+			List<FeedSubscription> subs = feedSubscriptionDAO.findByFeed(feed);
+			for (FeedSubscription sub : subs) {
+				sub.setFeed(into);
+			}
+			feedSubscriptionDAO.saveOrUpdate(subs);
+			feedDAO.delete(feed);
+		}
+		feedDAO.saveOrUpdate(into);
+	}
+
 }