From 2b4132493a7334708fd5bb0c19eac511b6211778 Mon Sep 17 00:00:00 2001
From: Paul Campbell <pcampbell@kemitix.net>
Date: Sat, 18 Feb 2017 18:21:23 +0000
Subject: [PATCH] Node: isRoot(): added

---
 src/main/java/net/kemitix/node/Node.java         |  7 +++++++
 src/main/java/net/kemitix/node/NodeItem.java     |  5 +++++
 src/test/java/net/kemitix/node/NodeItemTest.java | 15 +++++++++++++++
 3 files changed, 27 insertions(+)

diff --git a/src/main/java/net/kemitix/node/Node.java b/src/main/java/net/kemitix/node/Node.java
index 19351fa..6477681 100644
--- a/src/main/java/net/kemitix/node/Node.java
+++ b/src/main/java/net/kemitix/node/Node.java
@@ -82,6 +82,13 @@ public interface Node<T> {
      */
     boolean isEmpty();
 
+    /**
+     * Returns true is the node is a root node (has no parent).
+     *
+     * @return true is parent is null
+     */
+    boolean isRoot();
+
     /**
      * Fetch the parent node.
      *
diff --git a/src/main/java/net/kemitix/node/NodeItem.java b/src/main/java/net/kemitix/node/NodeItem.java
index 739df89..70724c5 100644
--- a/src/main/java/net/kemitix/node/NodeItem.java
+++ b/src/main/java/net/kemitix/node/NodeItem.java
@@ -113,6 +113,11 @@ class NodeItem<T> implements Node<T> {
         return data == null;
     }
 
+    @Override
+    public boolean isRoot() {
+        return parent == null;
+    }
+
     @Override
     public Optional<Node<T>> findParent() {
         return Optional.ofNullable(parent);
diff --git a/src/test/java/net/kemitix/node/NodeItemTest.java b/src/test/java/net/kemitix/node/NodeItemTest.java
index 73b7951..9e8504c 100644
--- a/src/test/java/net/kemitix/node/NodeItemTest.java
+++ b/src/test/java/net/kemitix/node/NodeItemTest.java
@@ -930,4 +930,19 @@ public class NodeItemTest {
                      .collect(Collectors.toList())).as("sub-tree")
                                                    .containsExactlyInAnyOrder(n1, n3, n5, n7);
     }
+
+    @Test
+    public void isRootWhenRootIsTrue() {
+        assertThat(Nodes.unnamedRoot(null)
+                        .isRoot()).isTrue();
+    }
+
+    @Test
+    public void isRootWhenNotRootIsFalse() {
+        //given
+        val root = Nodes.unnamedRoot(null);
+        //then
+        assertThat(Nodes.unnamedChild(null, root)
+                        .isRoot()).isFalse();
+    }
 }