Refactor group population logic in TurSolrResultProcessor

Split the group population logic into smaller methods for better readability and maintainability. Added null and empty checks for group responses and group values to prevent potential NullPointerExceptions.

Author: alegauss

turing-app/src/main/java/com/viglet/turing/solr/TurSolrResultProcessor.java

@@ -99,14 +99,34 @@ private void processGroups(SolrQuery query, TurSolrInstance turSolrInstance,
 
         private void populateGroupsFromResponse(QueryResponse queryResponse, TurSNSite turSNSite,
                         TurSolrQueryContext queryContext, List<TurSEGroup> turSEGroups) {
-                queryResponse.getGroupResponse().getValues()
-                                .forEach(groupCommand -> groupCommand.getValues()
-                                                .forEach(group -> Optional.ofNullable(group.getGroupValue())
-                                                                .ifPresent(g -> turSEGroups
-                                                                                .add(setTurSEGroup(turSNSite,
-                                                                                                queryContext,
-                                                                                                queryResponse,
-                                                                                                group)))));
+                var groupResponse = queryResponse.getGroupResponse();
+                if (groupResponse == null || CollectionUtils.isEmpty(groupResponse.getValues())) {
+                        return;
+                }
+
+                for (GroupCommand groupCommand : groupResponse.getValues()) {
+                        addGroupsFromCommand(turSNSite, queryContext, queryResponse, turSEGroups, groupCommand);
+                }
+        }
+
+        private void addGroupsFromCommand(TurSNSite turSNSite, TurSolrQueryContext queryContext,
+                        QueryResponse queryResponse, List<TurSEGroup> turSEGroups, GroupCommand groupCommand) {
+                if (CollectionUtils.isEmpty(groupCommand.getValues())) {
+                        return;
+                }
+
+                for (Group group : groupCommand.getValues()) {
+                        addGroupIfPresent(turSNSite, queryContext, queryResponse, turSEGroups, group);
+                }
+        }
+
+        private void addGroupIfPresent(TurSNSite turSNSite, TurSolrQueryContext queryContext,
+                        QueryResponse queryResponse, List<TurSEGroup> turSEGroups, Group group) {
+                if (group.getGroupValue() == null) {
+                        return;
+                }
+
+                turSEGroups.add(setTurSEGroup(turSNSite, queryContext, queryResponse, group));
         }
 
         private boolean shouldApplyWildcardQuery(TurSNSite turSNSite, SolrQuery query) {