// patterns/ShapeFactory2.java

// (c)2021 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 {

private Map<String, Constructor> factories =

new HashMap<>();

private 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);

}

}

@Override public Shape create(String id) {

try {

return (Shape)factories

.computeIfAbsent(id, ShapeFactory2::load)

.newInstance();

} catch(Exception 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

*/