From 36efe5d83ab5e3f63c6cf3cd208b54a19c1600ce Mon Sep 17 00:00:00 2001
From: Paul Campbell <pcampbell@kemitix.net>
Date: Tue, 24 May 2016 09:57:11 +0100
Subject: [PATCH] Node: may be empty, having no data

* isEmpty()
---
 src/main/java/net/kemitix/node/Node.java     | 7 +++++++
 src/main/java/net/kemitix/node/NodeItem.java | 5 +++++
 2 files changed, 12 insertions(+)

diff --git a/src/main/java/net/kemitix/node/Node.java b/src/main/java/net/kemitix/node/Node.java
index 002bead..2d9c67e 100644
--- a/src/main/java/net/kemitix/node/Node.java
+++ b/src/main/java/net/kemitix/node/Node.java
@@ -20,6 +20,13 @@ public interface Node<T> {
      */
     T getData();
 
+    /**
+     * Returns true if the node is empty (has no data).
+     *
+     * @return true is data is null
+     */
+    boolean isEmpty();
+
     /**
      * Fetch the parent node.
      * <p>
diff --git a/src/main/java/net/kemitix/node/NodeItem.java b/src/main/java/net/kemitix/node/NodeItem.java
index d11ff23..c3a3b45 100644
--- a/src/main/java/net/kemitix/node/NodeItem.java
+++ b/src/main/java/net/kemitix/node/NodeItem.java
@@ -50,6 +50,11 @@ public class NodeItem<T> implements Node<T> {
         return data;
     }
 
+    @Override
+    public boolean isEmpty() {
+        return data == null;
+    }
+
     @Override
     public Node<T> getParent() {
         return parent;