Implement referencing other nodes in graph

src/main/java/io/github/chronosx88/JGUN/api/PathReference.java

@@ -27,6 +27,10 @@ public class PathReference {
         this.storageManager = storageManager;
     }
 
+    public String[] getPath() {
+        return path.toArray(new String[0]);
+    }
+
     public PathReference get(String key) {
         path.add(key);
         return this;
@@ -120,4 +124,27 @@ public class PathReference {
             storageManager.addMapChangeListener(pathData.get(pathData.size()-1), mapListener);
         });
     }
+
+    public CompletableFuture<Result> put(PathReference nodeReference) {
+        String[] pathToAnotherNode = nodeReference.getPath();
+        return CompletableFuture.supplyAsync(() -> {
+            try {
+                return storageManager.getPathData(pathToAnotherNode);
+            } catch (TimeoutException | ExecutionException | InterruptedException e) {
+                throw new CompletionException(e);
+            }
+        }).thenComposeAsync(pathData -> {
+            if (pathData.size() < pathToAnotherNode.length) {
+                return CompletableFuture.failedFuture(new IllegalArgumentException("target node not found"));
+            }
+            String nodeId = pathData.get(pathData.size()-1);
+            MemoryGraph graph = new NodeBuilder()
+                    .add(path.get(path.size() - 1), NodeLinkValue.builder()
+                            .link(nodeId)
+                            .build())
+                    .build();
+            if (path.size() > 1) this.path.remove(path.size()-1);
+            return this.put(graph);
+        });
+    }
 }

src/main/java/io/github/chronosx88/JGUN/api/graph/NodeBuilder.java

@@ -91,6 +91,10 @@ public class NodeBuilder {
         return this;
     }
 
+    public NodeBuilder add(String name, NodeLinkValue link) {
+        return addScalar(name, link);
+    }
+
     public MemoryGraph build() {
         return this.graph;
     }

src/main/java/io/github/chronosx88/JGUN/examples/MainClient.java

@@ -18,14 +18,22 @@ public class MainClient {
         Storage storage = new MemoryStorage();
         NetworkNode peer = new NetworkNode(Inet4Address.getByAddress(new byte[]{127, 0, 0, 1}), 5054, storage);
         Gun gun = new Gun(storage, peer);
+
         Result result = gun.get("person").put(new NodeBuilder()
-                .add("firstName", "ABCD")
+                .add("firstName", "Test")
                 .build()).get();
         System.out.println(result);
+
         result = gun.get("person").get("address").put(new NodeBuilder()
-                .add("city", "HUY")
+                .add("city", "Dallas")
-                .add("ZIP", new NodeBuilder()
+                .build()).get();
-                        .add("post", "pochta rossii"))
+        System.out.println(result);
+
+        result = gun.get("person").get("homeAddress").put(gun.get("person").get("address")).get();
+        System.out.println(result);
+
+        result = gun.get("person").get("homeAddress").put(new NodeBuilder()
+                .add("city", "New YORK CITY")
                 .build()).get();
         System.out.println(result);
     }