// patterns/ShapeFactory2.java
// (c)2017 MindView LLC: see Copyright.txt
// We make no guarantees that this code is fit for any purpose.
// Visit http://OnJava8.com for more book information.
import java.util.*;
import java.lang.reflect.*;
import java.util.stream.*;
import patterns.shapes.*;

public class ShapeFactory2 implements FactoryMethod {
 Map<String, Constructor> factories =
 new HashMap<>();
 static Constructor load(String id) {
 System.out.println("loading " + id);
 try {
 return Class.forName("patterns.shapes." + id)
 .getConstructor();
 } catch(ClassNotFoundException |
 NoSuchMethodException e) {
 throw new BadShapeCreation(id);
 }
 }
 public Shape create(String id) {
 try {
 return (Shape)factories
 .computeIfAbsent(id, ShapeFactory2::load)
 .newInstance();
 } catch(InstantiationException |
 IllegalAccessException |
 InvocationTargetException e) {
 throw new BadShapeCreation(id);
 }
 }
 public static void main(String[] args) {
 FactoryTest.test(new ShapeFactory2());
 }
}
/* Output:
loading Circle
Circle[0] draw
Circle[0] erase
loading Square
Square[1] draw
Square[1] erase
loading Triangle
Triangle[2] draw
Triangle[2] erase
Square[3] draw
Square[3] erase
Circle[4] draw
Circle[4] erase
Circle[5] draw
Circle[5] erase
Triangle[6] draw
Triangle[6] erase
*/