CPS-1526 Fix response message for PATCH operation

- Fixed the Response code and message when trying to update multiple
  data trees at once
- Response code changed to 400
- Since the patch operation across multiple data trees is not
  supported when xpath is set to root node xpath, appropriate message is
  returned in response
- Existing functionality of updating one data node with root node xpath
  remains as it is.
- Updated API documentation and release notes

Issue-ID: CPS-1526
Signed-off-by: arpitsingh <as00745003@techmahindra.com>
Change-Id: I5d25a06bb5d407316ccfb2f85877cbe56a9f6f31

2 files changed, 12 insertions, 4 deletions

diff --git a/cps-service/src/main/java/org/onap/cps/api/CpsDataService.java b/cps-service/src/main/java/org/onap/cps/api/CpsDataService.java
index 39fa45ac1a..fc008685c1 100644
--- a/cps-service/src/main/java/org/onap/cps/api/CpsDataService.java
+++ b/cps-service/src/main/java/org/onap/cps/api/CpsDataService.java
@@ -138,7 +138,9 @@ public interface CpsDataService {
                                                        FetchDescendantsOption fetchDescendantsOption);
 
     /**
-     * Updates data node for given dataspace and anchor using xpath to parent node.
+     * Updates data node for given dataspace and anchor using xpath to parent node. This method can currently
+     * update only one top level data node. The method will throw DataValidationException when more than one top level
+     * data nodes are provided in jsonData
      *
      * @param dataspaceName   dataspace name
      * @param anchorName      anchor name
diff --git a/cps-service/src/main/java/org/onap/cps/api/impl/CpsDataServiceImpl.java b/cps-service/src/main/java/org/onap/cps/api/impl/CpsDataServiceImpl.java
index cd14795ad5..51e31f08c8 100755
--- a/cps-service/src/main/java/org/onap/cps/api/impl/CpsDataServiceImpl.java
+++ b/cps-service/src/main/java/org/onap/cps/api/impl/CpsDataServiceImpl.java
@@ -160,9 +160,15 @@ public class CpsDataServiceImpl implements CpsDataService {
         final String jsonData, final OffsetDateTime observedTimestamp) {
         cpsValidator.validateNameCharacters(dataspaceName, anchorName);
         final Anchor anchor = cpsAdminService.getAnchor(dataspaceName, anchorName);
-        final DataNode dataNode = buildDataNode(anchor, parentNodeXpath, jsonData, ContentType.JSON);
-        cpsDataPersistenceService.updateDataLeaves(dataspaceName, anchorName, dataNode.getXpath(),
-            dataNode.getLeaves());
+        final Collection<DataNode> dataNodesInPatch = buildDataNodes(anchor, parentNodeXpath, jsonData,
+                ContentType.JSON);
+        if (dataNodesInPatch.size() > 1) {
+            throw new DataValidationException("Operation is not supported for multiple data nodes",
+                    "Number of data nodes present: " + dataNodesInPatch.size());
+        }
+        cpsDataPersistenceService.updateDataLeaves(dataspaceName, anchorName,
+                dataNodesInPatch.iterator().next().getXpath(),
+            dataNodesInPatch.iterator().next().getLeaves());
         processDataUpdatedEventAsync(anchor, parentNodeXpath, UPDATE, observedTimestamp);
     }