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/* @test
 * @bug 8195649
 * @summary Basic functional test of OptionalDouble
 * @author Mike Duigou
 * @build ObscureException
 * @run testng BasicDouble
 */

import java.util.NoSuchElementException;
import java.util.OptionalDouble;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.function.DoublePredicate;
import java.util.List;

import static org.testng.Assert.*;
import org.testng.annotations.Test;

public class BasicDouble {
    static final double DOUBLEVAL = Math.PI;
    static final double UNEXPECTED = 6.62607004E-34;

    /**
     * Checks a block of assertions over an empty OptionalDouble.
     */
    void checkEmpty(OptionalDouble empty) {
        assertTrue(empty.equals(OptionalDouble.empty()));
        assertTrue(OptionalDouble.empty().equals(empty));
        assertFalse(empty.equals(OptionalDouble.of(UNEXPECTED)));
        assertFalse(OptionalDouble.of(UNEXPECTED).equals(empty));
        assertFalse(empty.equals("unexpected"));

        assertFalse(empty.isPresent());
        assertTrue(empty.isEmpty());
        assertEquals(empty.hashCode(), 0);
        assertEquals(empty.orElse(UNEXPECTED), UNEXPECTED);
        assertEquals(empty.orElseGet(() -> UNEXPECTED), UNEXPECTED);

        assertThrows(NoSuchElementException.class, () -> empty.getAsDouble());
        assertThrows(NoSuchElementException.class, () -> empty.orElseThrow());
        assertThrows(ObscureException.class,       () -> empty.orElseThrow(ObscureException::new));

        var b = new AtomicBoolean();
        empty.ifPresent(s -> b.set(true));
        assertFalse(b.get());

        var b1 = new AtomicBoolean(false);
        var b2 = new AtomicBoolean(false);
        empty.ifPresentOrElse(s -> b1.set(true), () -> b2.set(true));
        assertFalse(b1.get());
        assertTrue(b2.get());

        assertEquals(empty.toString(), "OptionalDouble.empty");
    }

    /**
     * Checks a block of assertions over an OptionalDouble that is expected to
     * have a particular value present.
     */
    void checkPresent(OptionalDouble opt, double expected) {
        assertFalse(opt.equals(OptionalDouble.empty()));
        assertFalse(OptionalDouble.empty().equals(opt));
        assertTrue(opt.equals(OptionalDouble.of(expected)));
        assertTrue(OptionalDouble.of(expected).equals(opt));
        assertFalse(opt.equals(OptionalDouble.of(UNEXPECTED)));
        assertFalse(OptionalDouble.of(UNEXPECTED).equals(opt));
        assertFalse(opt.equals("unexpected"));

        assertTrue(opt.isPresent());
        assertEquals(opt.hashCode(), Double.hashCode(expected));
        assertEquals(opt.orElse(UNEXPECTED), expected);
        assertEquals(opt.orElseGet(() -> UNEXPECTED), expected);

        assertEquals(opt.getAsDouble(), expected);
        assertEquals(opt.orElseThrow(), expected);
        assertEquals(opt.orElseThrow(ObscureException::new), expected);

        var b = new AtomicBoolean(false);
        opt.ifPresent(s -> b.set(true));
        assertTrue(b.get());

        var b1 = new AtomicBoolean(false);
        var b2 = new AtomicBoolean(false);
        opt.ifPresentOrElse(s -> b1.set(true), () -> b2.set(true));
        assertTrue(b1.get());
        assertFalse(b2.get());

        assertEquals(opt.toString(), "OptionalDouble[" + expected + "]");
    }

    @Test(groups = "unit")
    public void testEmpty() {
        checkEmpty(OptionalDouble.empty());
    }

    @Test(groups = "unit")
    public void testPresent() {
        checkPresent(OptionalDouble.of(DOUBLEVAL), DOUBLEVAL);
    }

    @Test(groups = "unit")
    public void testStreamEmpty() {
        assertEquals(OptionalDouble.empty().stream().toArray(), new double[] { });
    }

    @Test(groups = "unit")
    public void testStreamPresent() {
        assertEquals(OptionalDouble.of(DOUBLEVAL).stream().toArray(), new double[] { DOUBLEVAL });
    }

    @Test(groups = "unit")
    public void testIsEmpty() {
        OptionalDouble empty = OptionalDouble.empty();
        assertTrue(empty.isEmpty());
        OptionalDouble present = OptionalDouble.of(DOUBLEVAL);
        assertFalse(present.isEmpty());
        var doubleList = List.of(1.0, 2.0, 3.0, 4.0, 5.0);
        DoublePredicate isPositiveNumber = x -> x > 0;
        DoublePredicate isNegativeNumber = x -> x < 0;
        OptionalDouble positiveNumber = doubleList.stream().mapToDouble(Double::doubleValue).filter(isPositiveNumber).findAny();
        OptionalDouble negativeNumber = doubleList.stream().mapToDouble(Double::doubleValue).filter(isNegativeNumber).findAny();
        assertFalse(positiveNumber.isEmpty());
        assertTrue(negativeNumber.isEmpty());
    }

}