ATLAS-3269: fixed basic-search handing of search for entities with no-classication

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

@@ -176,8 +176,8 @@ public class ClassificationSearchProcessor extends SearchProcessor {
 
                 entityGraphQueryTraitNames = graph.query().or(orConditions);
                 entityPredicateTraitNames  = PredicateUtils.andPredicate(
-                        SearchPredicateUtil.getIsNullPredicateGenerator().generatePredicate(TRAIT_NAMES_PROPERTY_KEY, null, List.class),
-                        SearchPredicateUtil.getIsNullPredicateGenerator().generatePredicate(PROPAGATED_TRAIT_NAMES_PROPERTY_KEY, null, List.class));
+                        SearchPredicateUtil.getIsNullOrEmptyPredicateGenerator().generatePredicate(TRAIT_NAMES_PROPERTY_KEY, null, List.class),
+                        SearchPredicateUtil.getIsNullOrEmptyPredicateGenerator().generatePredicate(PROPAGATED_TRAIT_NAMES_PROPERTY_KEY, null, List.class));
             } else {
                 orConditions.add(graph.query().createChildQuery().in(TRAIT_NAMES_PROPERTY_KEY, typeAndSubTypes));
                 orConditions.add(graph.query().createChildQuery().in(PROPAGATED_TRAIT_NAMES_PROPERTY_KEY, typeAndSubTypes));

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

@@ -103,8 +103,8 @@ public class EntitySearchProcessor extends SearchProcessor {
             traitPredicate = PredicateUtils.orPredicate(SearchPredicateUtil.getNotEmptyPredicateGenerator().generatePredicate(TRAIT_NAMES_PROPERTY_KEY, null, List.class),
                                                         SearchPredicateUtil.getNotEmptyPredicateGenerator().generatePredicate(PROPAGATED_TRAIT_NAMES_PROPERTY_KEY, null, List.class));
         } else if (classificationType == MATCH_ALL_NOT_CLASSIFIED) {
-            traitPredicate = PredicateUtils.andPredicate(SearchPredicateUtil.getIsNullPredicateGenerator().generatePredicate(TRAIT_NAMES_PROPERTY_KEY, null, List.class),
-                                                         SearchPredicateUtil.getIsNullPredicateGenerator().generatePredicate(PROPAGATED_TRAIT_NAMES_PROPERTY_KEY, null, List.class));
+            traitPredicate = PredicateUtils.andPredicate(SearchPredicateUtil.getIsNullOrEmptyPredicateGenerator().generatePredicate(TRAIT_NAMES_PROPERTY_KEY, null, List.class),
+                                                         SearchPredicateUtil.getIsNullOrEmptyPredicateGenerator().generatePredicate(PROPAGATED_TRAIT_NAMES_PROPERTY_KEY, null, List.class));
         } else {
             traitPredicate = PredicateUtils.orPredicate(SearchPredicateUtil.getContainsAnyPredicateGenerator().generatePredicate(TRAIT_NAMES_PROPERTY_KEY, classificationTypeAndSubTypes, List.class),
                                                         SearchPredicateUtil.getContainsAnyPredicateGenerator().generatePredicate(PROPAGATED_TRAIT_NAMES_PROPERTY_KEY, classificationTypeAndSubTypes, List.class));

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

@@ -650,6 +650,50 @@ public class SearchPredicateUtil {
         return ret;
     }
 
+    public static VertexAttributePredicateGenerator getIsNullOrEmptyPredicateGenerator() {
+        if (LOG.isDebugEnabled()) {
+            LOG.debug("==> getIsNullOrEmptyPredicateGenerator");
+        }
+
+        VertexAttributePredicateGenerator ret = new VertexAttributePredicateGenerator() {
+            @Override
+            public Predicate generatePredicate(final String attrName, final Object attrVal, final Class attrClass) {
+                final Predicate ret;
+
+                if (attrName == null || attrClass == null) {
+                    ret = ALWAYS_FALSE;
+                } else {
+                    ret = new VertexAttributePredicate(attrName, attrClass, true) {
+                        @Override
+                        protected boolean compareValue(final Object vertexAttrVal) {
+                            final boolean ret;
+
+                            if (vertexAttrVal == null) {
+                                ret = true;
+                            } else if (vertexAttrVal instanceof Collection) {
+                                ret = CollectionUtils.isEmpty((Collection) vertexAttrVal);
+                            } else if (vertexAttrVal instanceof String) {
+                                ret = StringUtils.isEmpty((String) vertexAttrVal);
+                            } else {
+                                ret = false;
+                            }
+
+                            return ret;
+                        }
+                    };
+                }
+
+                return ret;
+            }
+        };
+
+        if (LOG.isDebugEnabled()) {
+            LOG.debug("<== getIsNullOrEmptyPredicateGenerator");
+        }
+
+        return ret;
+    }
+
     public interface VertexAttributePredicateGenerator {
         Predicate generatePredicate(String attrName, Object attrVal, Class attrClass);
     }