Optimize Entities capacity to avoid reallocation (#145)

* Optimize Entities capacity to avoid reallocation

Author: sazzad16

src/main/java/com/redislabs/redisgraph/graph_entities/Edge.java

@@ -9,11 +9,22 @@
 public class Edge extends GraphEntity {
 
     //members
-    private  String relationshipType;
+    private String relationshipType;
     private long source;
     private long destination;
 
+    public Edge() {
+        super();
+    }
 
+    /**
+     * Use this constructor to reduce memory allocations
+     * when properties are added to the edge
+     * @param propertiesCapacity preallocate the capacity for the properties
+     */
+    public Edge(int propertiesCapacity) {
+        super(propertiesCapacity);
+    }
     //getters & setters
 
     /**

src/main/java/com/redislabs/redisgraph/graph_entities/GraphEntity.java

@@ -10,8 +10,20 @@
 public abstract class GraphEntity {
     //members
     protected long id;
-    protected final Map<String, Property<?>> propertyMap = new HashMap<>();
+    protected final Map<String, Property<?>> propertyMap;
 
+    public GraphEntity() {
+        propertyMap = new HashMap<>();
+    }
+
+    /**
+     * Use this constructor to reduce memory allocations 
+     * when properties are added to the edge
+     * @param propertiesCapacity preallocate the capacity for the properties
+     */
+    public GraphEntity(int propertiesCapacity) {
+        propertyMap = new HashMap<>(propertiesCapacity);
+    }
 
     //setters & getters
 

src/main/java/com/redislabs/redisgraph/graph_entities/Node.java

@@ -10,7 +10,24 @@
 public class Node extends GraphEntity {
 
     //members
-    private final List<String> labels = new ArrayList<>();
+    private final List<String> labels;
+
+    public Node() {
+        super();
+        labels = new ArrayList<>();
+    }
+
+    /**
+     * Use this constructor to reduce memory allocations 
+     * when labels or properties are added to the node
+     * @param labelsCapacity preallocate the capacity for the node labels
+     * @param propertiesCapacity preallocate the capacity for the properties
+     */
+    public Node(int labelsCapacity, int propertiesCapacity) {
+        super(propertiesCapacity);
+        this.labels = new ArrayList<>(labelsCapacity);
+    }
+
 
     /**
      * @param label - a label to be add

src/main/java/com/redislabs/redisgraph/impl/resultset/ResultSetImpl.java

@@ -140,26 +140,28 @@ public Header getHeader() {
      */
     @SuppressWarnings("unchecked")
     private Node deserializeNode(List<Object> rawNodeData) {
-        Node node = new Node();
-        deserializeGraphEntityId(node, rawNodeData.get(0));
+
         List<Long> labelsIndices = (List<Long>) rawNodeData.get(1);
+        List<List<Object>> rawProperties = (List<List<Object>>) rawNodeData.get(2);
+
+        Node node = new Node(labelsIndices.size(), rawProperties.size());
+        deserializeGraphEntityId(node, (Long) rawNodeData.get(0));
+
         for (Long labelIndex : labelsIndices) {
             String label = cache.getLabel(labelIndex.intValue(), redisGraph);
             node.addLabel(label);
         }
-        deserializeGraphEntityProperties(node, (List<List<Object>>) rawNodeData.get(2));
 
-        return node;
+        deserializeGraphEntityProperties(node, rawProperties);
 
+        return node;
     }
 
     /**
      * @param graphEntity graph entity
-     * @param rawEntityId raw representation of entity id to be set to the graph
-     *                    entity
+     * @param id entity id to be set to the graph entity
      */
-    private void deserializeGraphEntityId(GraphEntity graphEntity, Object rawEntityId) {
-        long id = (Long) rawEntityId;
+    private void deserializeGraphEntityId(GraphEntity graphEntity, long id) {
         graphEntity.setId(id);
     }
 
@@ -172,16 +174,19 @@ private void deserializeGraphEntityId(GraphEntity graphEntity, Object rawEntityI
      */
     @SuppressWarnings("unchecked")
     private Edge deserializeEdge(List<Object> rawEdgeData) {
-        Edge edge = new Edge();
-        deserializeGraphEntityId(edge, rawEdgeData.get(0));
+
+        List<List<Object>> rawProperties = (List<List<Object>>) rawEdgeData.get(4);
+
+        Edge edge = new Edge(rawProperties.size());
+        deserializeGraphEntityId(edge, (Long) rawEdgeData.get(0));
 
         String relationshipType = cache.getRelationshipType(((Long) rawEdgeData.get(1)).intValue(), redisGraph);
         edge.setRelationshipType(relationshipType);
 
         edge.setSource((long) rawEdgeData.get(2));
         edge.setDestination((long) rawEdgeData.get(3));
 
-        deserializeGraphEntityProperties(edge, (List<List<Object>>) rawEdgeData.get(4));
+        deserializeGraphEntityProperties(edge, rawProperties);
 
         return edge;
     }
@@ -256,8 +261,11 @@ private Object deserializePoint(Object rawScalarData) {
     @SuppressWarnings("unchecked")
     private Map<String, Object> deserializeMap(Object rawScalarData) {
         List<Object> keyTypeValueEntries = (List<Object>) rawScalarData;
-        Map<String, Object> map = new HashMap<>();
-        for (int i = 0; i < keyTypeValueEntries.size(); i += 2) {
+
+        int size = keyTypeValueEntries.size();
+        Map<String, Object> map = new HashMap<>(size >> 1); // set the capacity to half of the list
+
+        for (int i = 0; i < size; i += 2) {
             String key = SafeEncoder.encode((byte[]) keyTypeValueEntries.get(i));
             Object value = deserializeScalar((List<Object>) keyTypeValueEntries.get(i + 1));
             map.put(key, value);