added visitor pattern sample

visitor/src/main/java/com/iluwatar/Unit.java

@@ -0,0 +1,16 @@
+package com.iluwatar;
+
+public abstract class Unit {
+
+	private Unit[] children;
+
+	public Unit(Unit ... children) {
+		this.children = children;
+	}
+	
+	public void accept(UnitVisitor visitor) {
+		for (Unit child: children) {
+			child.accept(visitor);
+		}
+	}
+}