beta, Added from and size controls

intg/src/main/java/org/apache/atlas/model/discovery/IndexSearchParams.java

@@ -18,7 +18,6 @@ public class IndexSearchParams extends SearchParams {
     private String purpose;
     private String persona;
     private String queryString;
-
     /*
     * Indexsearch includes all relations (if requested with param attributes) even if relationshipStatus is DELETED
     * Changing this behaviour to exclude related attributes which has relationshipStatus as DELETED
@@ -43,6 +42,20 @@ public void setDsl(Map dsl) {
         queryString = AtlasType.toJson(dsl);
     }
 
+    public Integer getFrom() {
+        if (dsl != null && dsl.containsKey("from")) {
+            return (Integer) dsl.get("from");
+        }
+        return null;
+    }
+
+    public Integer getSize() {
+        if (dsl != null && dsl.containsKey("size")) {
+            return (Integer) dsl.get("size");
+        }
+        return null;
+    }
+
     public boolean isAllowDeletedRelations() {
         return allowDeletedRelations;
     }

repository/src/main/java/org/apache/atlas/repository/graph/GraphHelper.java

@@ -540,12 +540,8 @@ public static List<String> getPropagatedVerticesIds (AtlasVertex classificationV
     }
 
     public static boolean hasEntityReferences(AtlasVertex classificationVertex) {
-        boolean ret = false;
         Iterator edgeIterator = classificationVertex.query().direction(AtlasEdgeDirection.IN).label(CLASSIFICATION_LABEL).edges(1).iterator();
-        if (edgeIterator != null && edgeIterator.hasNext()) {
-            ret = true;
-        }
-        return ret;
+        return edgeIterator != null && edgeIterator.hasNext();
     }
 
     public static List<AtlasVertex> getAllPropagatedEntityVertices(AtlasVertex classificationVertex) {

webapp/src/main/java/org/apache/atlas/web/rest/DiscoveryREST.java

@@ -408,6 +408,14 @@ public AtlasSearchResult indexSearch(@Context HttpServletRequest servletRequest,
                 throw abe;
             }
 
+            if (parameters.getFrom() > 10000) {
+                throw new AtlasBaseException(AtlasErrorCode.BAD_REQUEST, "Invalid search query: 'from' parameter is more than 10000, Use search_after parameter for pagination.");
+            }
+
+            if (parameters.getSize() > 20) {
+                throw new AtlasBaseException(AtlasErrorCode.BAD_REQUEST, "Invalid search query: 'size' parameter is more than 20, 'size' parameter can only be less than equal to 20");
+            }
+
             if(LOG.isDebugEnabled()){
                 LOG.debug("Performing indexsearch for the params ({})", parameters);
             }