54 lines
1.2 KiB
Java
54 lines
1.2 KiB
Java
// patterns/ShapeFactory3.java
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// (c)2021 MindView LLC: see Copyright.txt
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// We make no guarantees that this code is fit for any purpose.
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// Visit http://OnJava8.com for more book information.
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// Polymorphic factory methods.
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import java.util.*;
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import java.util.function.*;
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import java.util.stream.*;
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import patterns.shapes.*;
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interface PolymorphicFactory {
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Shape create();
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}
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class RandomShapes implements Supplier<Shape> {
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private final PolymorphicFactory[] factories;
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private Random rand = new Random(42);
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RandomShapes(PolymorphicFactory... factories) {
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this.factories = factories;
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}
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@Override public Shape get() {
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return
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factories[rand.nextInt(factories.length)]
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.create();
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}
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}
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public class ShapeFactory3 {
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public static void main(String[] args) {
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RandomShapes rs = new RandomShapes( // [1]
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Circle::new, Square::new, Triangle::new
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);
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Stream.generate(rs)
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.limit(6)
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.peek(Shape::draw)
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.peek(Shape::erase)
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.count();
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}
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}
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/* Output:
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Triangle[0] draw
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Triangle[0] erase
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Circle[1] draw
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Circle[1] erase
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Circle[2] draw
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Circle[2] erase
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Triangle[3] draw
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Triangle[3] erase
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Circle[4] draw
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Circle[4] erase
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Square[5] draw
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Square[5] erase
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*/
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