30 lines
798 B
Java
30 lines
798 B
Java
import java.util.Optional;
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public final class MonadMaybe {
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public static void main(String[] aArgs) {
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System.out.println(doubler(5).flatMap(MonadMaybe::stringify).get());
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System.out.println(doubler(2).flatMap(MonadMaybe::stringifyNullable).get());
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Optional<String> option = doubler(0).flatMap(MonadMaybe::stringifyNullable);
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String result = option.isPresent() ? option.get() : "Result is Null";
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System.out.println(result);
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}
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private static Optional<Integer> doubler(int aN) {
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return Optional.of(2 * aN);
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}
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private static Optional<String> stringify(int aN) {
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return Optional.of("A".repeat(aN));
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}
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private static Optional<String> stringifyNullable(int aN) {
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return ( aN > 0 ) ? Optional.ofNullable("A".repeat(aN)) : Optional.ofNullable(null);
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}
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}
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