ALF-9153 Avoid fetching too much un-used data when rendering a Discussions Topic to JSON with the reply count

git-svn-id: https://svn.alfresco.com/repos/alfresco-enterprise/alfresco/HEAD/root@29773 c4b6b30b-aa2e-2d43-bbcb-ca4b014f7261

source/java/org/alfresco/repo/discussion/DiscussionServiceImpl.java

@@ -477,7 +477,8 @@ public class DiscussionServiceImpl implements DiscussionService
     }
 
     @Override
-    public PostInfo getPrimaryPost(TopicInfo topic) {
+    public PostInfo getPrimaryPost(TopicInfo topic) 
+    {
        // First up, see if there is a post with the same name as the topic
        // (That's the normal Share case)
        PostInfo post = getPost(topic, topic.getSystemName());
@@ -500,6 +501,41 @@ public class DiscussionServiceImpl implements DiscussionService
        return buildPost(postNodeRef, topic, postName, null);
     }
     
+    @Override
+    public PostInfo getMostRecentPost(TopicInfo topic)
+    {
+       // Do a listing at the Node level, ordered by created date
+       //  to get the most recent nodes
+       NodeBackedEntity node = null;
+       int skip = 0;
+       int pageSize = 10000;
+       while(node == null)
+       {
+          PagingRequest paging = new PagingRequest(skip, pageSize);
+          paging.setRequestTotalCountMax(skip+pageSize+10);
+          CannedQueryResults<NodeBackedEntity> results = 
+             listEntries(topic.getNodeRef(), ForumModel.TYPE_POST, null, paging);
+          
+          // Move to the next page if we're not at the end
+          if(results.hasMoreItems())
+          {
+             skip += pageSize;
+             continue;
+          }
+          // Bail if the topic lacks posts
+          if(results.getPage().size() == 0)
+          {
+             // No posts in the topic
+             return null;
+          }
+          // Grab the last node
+          node = results.getPage().get(results.getPage().size()-1);
+       }
+       
+       // Wrap and return
+       return buildPost(node.getNodeRef(), topic, node.getName(), null);
+    }
+
    
    @Override
    public PagingResults<TopicInfo> listTopics(String siteShortName,

source/java/org/alfresco/repo/discussion/DiscussionServiceImplTest.java

@@ -246,6 +246,8 @@ public class DiscussionServiceImplTest
           
           // The topic has no primary post
           assertEquals(null, DISCUSSION_SERVICE.getPrimaryPost(topic));
+          // Which means no recent post
+          assertEquals(null, DISCUSSION_SERVICE.getMostRecentPost(topic));
           
           
           // Get with an arbitrary name gives nothing
@@ -289,6 +291,10 @@ public class DiscussionServiceImplTest
           assertNotNull(DISCUSSION_SERVICE.getPrimaryPost(topic));
           assertEquals(post.getNodeRef(), DISCUSSION_SERVICE.getPrimaryPost(topic).getNodeRef());
           
+          // The new post will be the most recent one
+          assertNotNull(DISCUSSION_SERVICE.getMostRecentPost(topic));
+          assertEquals(post.getNodeRef(), DISCUSSION_SERVICE.getMostRecentPost(topic).getNodeRef());
+
           
           // Topic will now have one post listed
           posts = DISCUSSION_SERVICE.listPosts(topic, new PagingRequest(10));
@@ -357,6 +363,15 @@ public class DiscussionServiceImplTest
           assertEquals(reply1.getNodeRef(), objects.getSecond().getNodeRef());
           
           
+          // The primary post will be unchanged
+          assertNotNull(DISCUSSION_SERVICE.getPrimaryPost(topic));
+          assertEquals(post.getNodeRef(), DISCUSSION_SERVICE.getPrimaryPost(topic).getNodeRef());
+          
+          // But the most recent will be the newest reply
+          assertNotNull(DISCUSSION_SERVICE.getMostRecentPost(topic));
+          assertEquals(reply2.getNodeRef(), DISCUSSION_SERVICE.getMostRecentPost(topic).getNodeRef());
+
+          
           // Check the overall count now
           posts = DISCUSSION_SERVICE.listPosts(topic, new PagingRequest(10));
           assertEquals(3, posts.getPage().size());

source/java/org/alfresco/service/cmr/discussion/DiscussionService.java

@@ -124,6 +124,17 @@ public interface DiscussionService {
    @NotAuditable
    PostInfo getPrimaryPost(TopicInfo topic);
    
+   /**
+    * Retrieves the newest (most recent) Post in a topic, be that 
+    *  the Primary Post or a Reply.
+    * This is typically used when identifying if a topic has had
+    *  new posts added to it since the user last saw it.
+    * Note that this works on Created Date, and not Modified/Updated,
+    *  so edits to an existing post will not change this.
+    */
+   @NotAuditable
+   PostInfo getMostRecentPost(TopicInfo topic);
+   
    /**
     * Retrieves an existing {@link TopicInfo} from the repository,
     *  which is within a site