refact: let kout degree applied to all labels & remove source vertex from kneighbor default results

hugegraph-core/src/main/java/com/baidu/hugegraph/backend/tx/GraphTransaction.java

@@ -72,6 +72,7 @@
 import com.baidu.hugegraph.iterator.ExtendableIterator;
 import com.baidu.hugegraph.iterator.FilterIterator;
 import com.baidu.hugegraph.iterator.FlatMapperIterator;
+import com.baidu.hugegraph.iterator.LimitIterator;
 import com.baidu.hugegraph.iterator.ListIterator;
 import com.baidu.hugegraph.iterator.MapperIterator;
 import com.baidu.hugegraph.iterator.WrappedIterator;
@@ -1995,47 +1996,4 @@ private <T> void traverseByLabel(SchemaLabel label,
             } while (page != null);
         }
     }
-
-    // TODO: move to common module
-    public static class LimitIterator<T> extends WrappedIterator<T> {
-
-        private final Iterator<T> originIterator;
-        private final Function<T, Boolean> filterCallback;
-
-        public LimitIterator(Iterator<T> origin, Function<T, Boolean> filter) {
-            this.originIterator = origin;
-            this.filterCallback = filter;
-        }
-
-        @Override
-        protected Iterator<T> originIterator() {
-            return this.originIterator;
-        }
-
-        @Override
-        protected final boolean fetch() {
-            while (this.originIterator.hasNext()) {
-                T next = this.originIterator.next();
-                // Do filter
-                boolean reachLimit = this.filterCallback.apply(next);
-                if (reachLimit) {
-                    this.closeOriginIterator();
-                    return false;
-                }
-                if (next != null) {
-                    assert this.current == none();
-                    this.current = next;
-                    return true;
-                }
-            }
-            return false;
-        }
-
-        protected final void closeOriginIterator() {
-            if (this.originIterator == null) {
-                return;
-            }
-            close(this.originIterator);
-        }
-    }
 }

hugegraph-core/src/main/java/com/baidu/hugegraph/traversal/algorithm/HugeTraverser.java

@@ -48,6 +48,7 @@
 import com.baidu.hugegraph.exception.NotFoundException;
 import com.baidu.hugegraph.iterator.ExtendableIterator;
 import com.baidu.hugegraph.iterator.FilterIterator;
+import com.baidu.hugegraph.iterator.LimitIterator;
 import com.baidu.hugegraph.iterator.MapperIterator;
 import com.baidu.hugegraph.schema.SchemaLabel;
 import com.baidu.hugegraph.structure.HugeEdge;
@@ -148,7 +149,8 @@ protected Set<Node> adjacentVertices(Set<Node> vertices, EdgeStep step,
             while (edges.hasNext()) {
                 Id target = ((HugeEdge) edges.next()).id().otherVertexId();
                 KNode kNode = new KNode(target, (KNode) source);
-                if (excluded != null && excluded.contains(kNode)) {
+                if ((excluded != null && excluded.contains(kNode)) ||
+                    neighbors.contains(kNode)) {
                     continue;
                 }
                 neighbors.add(kNode);
@@ -182,10 +184,17 @@ protected Iterator<Edge> edgesOfVertex(Id source, Directions dir,
         ExtendableIterator<Edge> results = new ExtendableIterator<>();
         for (Id label : labels.keySet()) {
             E.checkNotNull(label, "edge label");
-            // TODO: limit should be applied to all labels
             results.extend(this.edgesOfVertex(source, dir, label, limit));
         }
-        return results;
+
+        if (limit == NO_LIMIT) {
+            return results;
+        }
+
+        long[] count = new long[1];
+        return new LimitIterator<>(results, e -> {
+            return count[0]++ >= limit;
+        });
     }
 
     protected Iterator<Edge> edgesOfVertex(Id source, EdgeStep edgeStep) {

hugegraph-core/src/main/java/com/baidu/hugegraph/traversal/algorithm/KneighborTraverser.java

@@ -86,7 +86,6 @@ public Set<Node> customizedKneighbor(Id source, EdgeStep step, int maxDepth,
         Node sourceV = new KNode(source, null);
 
         latest.add(sourceV);
-        all.add(sourceV);
 
         while (maxDepth-- > 0) {
             long remaining = limit == NO_LIMIT ? NO_LIMIT : limit - all.size();