53 lines
1.2 KiB
Java
53 lines
1.2 KiB
Java
|
// patterns/ShapeFactory3.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.
|
||
|
|
// Polymorphic factory methods
|
||
|
|
import java.util.*;
|
||
|
|
import java.util.function.*;
|
||
|
|
import java.util.stream.*;
|
||
|
|
import patterns.shapes.*;
|
||
|
|
|
||
|
|
interface PolymorphicFactory {
|
||
|
|
Shape create();
|
||
|
|
}
|
||
|
|
|
||
|
|
class RandomShapes implements Supplier<Shape> {
|
||
|
|
private final PolymorphicFactory[] factories;
|
||
|
|
private Random rand = new Random(42);
|
||
|
|
RandomShapes(PolymorphicFactory... factories) {
|
||
|
|
this.factories = factories;
|
||
|
|
}
|
||
|
|
public Shape get() {
|
||
|
|
return factories[
|
||
|
|
rand.nextInt(factories.length)].create();
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
public class ShapeFactory3 {
|
||
|
|
public static void main(String[] args) {
|
||
|
|
RandomShapes rs = new RandomShapes(
|
||
|
|
Circle::new, Square::new, Triangle::new
|
||
|
|
);
|
||
|
|
Stream.generate(rs)
|
||
|
|
.limit(6)
|
||
|
|
.peek(Shape::draw)
|
||
|
|
.peek(Shape::erase)
|
||
|
|
.count();
|
||
|
|
}
|
||
|
|
}
|
||
|
|
/* Output:
|
||
|
|
Triangle[0] draw
|
||
|
|
Triangle[0] erase
|
||
|
|
Circle[1] draw
|
||
|
|
Circle[1] erase
|
||
|
|
Circle[2] draw
|
||
|
|
Circle[2] erase
|
||
|
|
Triangle[3] draw
|
||
|
|
Triangle[3] erase
|
||
|
|
Circle[4] draw
|
||
|
|
Circle[4] erase
|
||
|
|
Square[5] draw
|
||
|
|
Square[5] erase
|
||
|
|
*/
|