Rating Service. Now limited to one rating scheme per user per node.

Without an explicit requirement for multiple rating schemes being applied to a node by a user and in order to simplify
the code and ease maintenance, the RatingService now only supports one rating scheme per node per user.
A rating can be applied, removed and a new rating in another scheme applied. But if the first is not removed, an exception will be thrown by the service.

This change was a simple edit in the model with changes to the service implementation and test code.


git-svn-id: https://svn.alfresco.com/repos/alfresco-enterprise/alfresco/HEAD/root@21585 c4b6b30b-aa2e-2d43-bbcb-ca4b014f7261

source/java/org/alfresco/repo/rating/script/ScriptRatingService.java

@@ -26,6 +26,7 @@ import org.alfresco.repo.jscript.ScriptNode;
 import org.alfresco.service.ServiceRegistry;
 import org.alfresco.service.cmr.rating.Rating;
 import org.alfresco.service.cmr.rating.RatingService;
+import org.alfresco.service.cmr.rating.RatingServiceException;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 
@@ -92,10 +93,13 @@ public class ScriptRatingService extends BaseScopableProcessorExtension
      * Applies the given rating to the specified node using the specified ratingScheme.
      * It is the responsibility of the caller to ensure that the rating scheme exists
      * and that the rating is within the limits defined for that scheme.
+     * <p/>Furthermore, only one rating scheme per user per target node is supported. Any attempt
+     * by one user to apply a second rating in a different scheme will result in a {@link RatingServiceException}.
      * 
      * @param node
      * @param rating
      * @param ratingSchemeName
+     * @throws RatingServiceException
      * @see ScriptRatingService#getMin(String)
      * @see ScriptRatingService#getMax(String)
      */