39 lines
1.2 KiB
Java
39 lines
1.2 KiB
Java
// reflection/pets/Creator.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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// Creates random Pets
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package reflection.pets;
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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 java.lang.reflect.InvocationTargetException;
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public abstract class Creator implements Supplier<Pet> {
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private Random rand = new Random(47);
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// The different types of Pet to create:
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public abstract List<Class<? extends Pet>> types();
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@Override public Pet get() { // Create one random Pet
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int n = rand.nextInt(types().size());
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try {
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return types().get(n)
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.getConstructor().newInstance();
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} catch(InstantiationException |
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NoSuchMethodException |
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InvocationTargetException |
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IllegalAccessException e) {
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throw new RuntimeException(e);
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}
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}
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public Stream<Pet> stream() {
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return Stream.generate(this);
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}
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public Pet[] array(int size) {
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return stream().limit(size).toArray(Pet[]::new);
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}
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public List<Pet> list(int size) {
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return stream().limit(size)
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.collect(Collectors.toCollection(ArrayList::new));
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}
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}
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