Node:drawTree(): creates a String representing the node in the tree

The NodeItem implementation on includes nodes with names, or where they
have child nodes. In which case the are shown as '(unnamed)'.

src/main/java/net/kemitix/node/Node.java

@@ -146,6 +146,16 @@ public interface Node<T> {
      */
     Node<T> getChildNamed(String name);
 
+    /**
+     * Draw a representation of the tree.
+     *
+     * @param depth current depth for recursion
+     *
+     * @return a representation of the tree
+     */
+    String drawTree(int depth);
+
+    /**
      * Returns true if the Node has a name.
      *
      * @return true if the node has a name

src/main/java/net/kemitix/node/NodeItem.java

@@ -305,6 +305,21 @@ public class NodeItem<T> implements Node<T> {
         throw new NodeException("Named child not found");
     }
 
+    @Override
+    public String drawTree(final int depth) {
+        final StringBuilder sb = new StringBuilder();
+        final String unnamed = "(unnamed)";
+        if (isNamed()) {
+            sb.append(String.format("[%1$" + (depth + name.length()) + "s]\n",
+                    name));
+        } else if (!children.isEmpty()) {
+            sb.append(String.format("[%1$" + (depth + unnamed) + "s]\n",
+                    unnamed));
+        }
+        getChildren().stream().forEach(c -> sb.append(c.drawTree(depth + 1)));
+        return sb.toString();
+    }
+
     @Override
     public boolean isNamed() {
         return name != null && name.length() > 0;