ATLAS-2304: fix Relationship search API to work TinkerPop3

repository/src/main/java/org/apache/atlas/discovery/EntityDiscoveryService.java

@@ -608,11 +608,11 @@ public class EntityDiscoveryService implements AtlasDiscoveryService {
             }
 
             if (ret.getEntities() == null) {
-                ret.setEntities(new ArrayList<AtlasEntityHeader>());
+                ret.setEntities(new ArrayList<>());
             }
         } catch (ScriptException e) {
             if (LOG.isDebugEnabled()) {
-                LOG.debug("Gremlin script execution failed for relationship search query: " + e);
+                LOG.debug("Gremlin script execution failed for relationship search query: {}", relatedEntitiesQuery, e);
             }
 
             throw new AtlasBaseException(AtlasErrorCode.INTERNAL_ERROR, "Relationship search query failed");

repository/src/main/java/org/apache/atlas/util/AtlasGremlin3QueryProvider.java

@@ -23,6 +23,10 @@ public class AtlasGremlin3QueryProvider extends AtlasGremlin2QueryProvider {
         // In case any overrides are necessary, a specific switch case can be added here to
         // return Gremlin 3 specific query otherwise delegate to super.getQuery
         switch (gremlinQuery) {
+            case TYPE_UNUSED_COUNT_METRIC:
+                return "g.V().has('__type', 'typeSystem').filter({ !it.getProperty('__type.category').name().matches('TRAIT') && it.inE().count() == 0}).count()";
+            case ENTITY_COUNT_METRIC:
+                return "g.V().has('__superTypeNames', within(['Referenceable'])).count()";
             case EXPORT_TYPE_STARTS_WITH:
                 return "g.V().has('__typeName',typeName).filter({it.get().value(attrName).startsWith(attrValue)}).has('__guid').values('__guid').toList()";
             case EXPORT_TYPE_ENDS_WITH:
@@ -33,6 +37,8 @@ public class AtlasGremlin3QueryProvider extends AtlasGremlin2QueryProvider {
                 return "g.V().has('__typeName',typeName).filter({it.get().value(attrName).matches(attrValue)}).has('__guid').values('__guid').toList()";
             case EXPORT_TYPE_DEFAULT:
                 return "g.V().has('__typeName',typeName).has(attrName, attrValue).has('__guid').values('__guid').toList()";
+            case EXPORT_BY_GUID_FULL:
+                return "g.V().has('__guid', startGuid).bothE().bothV().has('__guid').transform{[__guid:it.__guid,isProcess:(it.__superTypeNames != null) ? it.__superTypeNames.contains('Process') : false ]}.dedup().toList()";
             case EXPORT_BY_GUID_CONNECTED_IN_EDGE:
                 return "g.V().has('__guid', startGuid).inE().outV().has('__guid').project('__guid', 'isProcess').by('__guid').by(map {it.get().values('__superTypeNames').toSet().contains('Process')}).dedup().toList()";
             case EXPORT_BY_GUID_CONNECTED_OUT_EDGE:
@@ -45,6 +51,14 @@ public class AtlasGremlin3QueryProvider extends AtlasGremlin2QueryProvider {
                 return "g.V().has('__guid', '%s').repeat(__.in('%s').out('%s')).times(%s)." +
                         "emit(has('__superTypeNames').and().properties('__superTypeNames').hasValue('DataSet'))." +
                         "path().toList()";
+            case TO_RANGE_LIST:
+                return ".range(startIdx, endIdx).toList()";
+            case RELATIONSHIP_SEARCH:
+                return "g.V().has('__guid', guid).both(relation).has('__state', within(states))";
+            case RELATIONSHIP_SEARCH_ASCENDING_SORT:
+                return ".order().by(sortAttributeName, incr)";
+            case RELATIONSHIP_SEARCH_DESCENDING_SORT:
+                return ".order().by(sortAttributeName, decr)";
             case GREMLIN_SEARCH_RETURNS_VERTEX_ID:
                 return "g.V().range(0,1).toList()";
             case GREMLIN_SEARCH_RETURNS_EDGE_ID: