added abstract-factory sample

abstract-factory/src/main/java/com/iluwatar/ElfKingdomFactory.java

@@ -0,0 +1,17 @@
+package com.iluwatar;
+
+public class ElfKingdomFactory implements KingdomFactory {
+
+	public Castle createCastle() {
+		return new ElfCastle();
+	}
+
+	public King createKing() {
+		return new ElfKing();
+	}
+
+	public Army createArmy() {
+		return new ElfArmy();
+	}
+
+}