103 lines
3.5 KiB
Java
103 lines
3.5 KiB
Java
/*
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* Copyright (c) 2023, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*/
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import java.util.LinkedList;
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import java.util.List;
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import java.util.stream.Gatherers;
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import java.util.stream.Stream;
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import org.junit.jupiter.api.Test;
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import org.junit.jupiter.params.ParameterizedTest;
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import org.junit.jupiter.params.provider.MethodSource;
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import static org.junit.jupiter.api.Assertions.*;
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import static org.junit.jupiter.api.Assumptions.*;
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/**
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* @test
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* @summary Tests the API and contract of Gatherers.scan
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* @run junit GatherersScanTest
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*/
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public class GatherersScanTest {
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record Config(int streamSize, boolean parallel) {
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Stream<Integer> stream() {
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var stream = Stream.iterate(1, i -> i + 1).limit(streamSize);
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stream = parallel ? stream.parallel() : stream.sequential();
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return stream;
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}
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}
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static final Stream<Integer> sizes(){
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return Stream.of(0,1,10,33,99,9999);
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}
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static final Stream<Config> sequentialAndParallel(int size) {
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return Stream.of(false, true)
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.map(parallel ->
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new Config(size, parallel));
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}
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static final Stream<Config> configurations() {
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return sizes().flatMap(i -> sequentialAndParallel(i));
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}
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@Test
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public void throwsNPEWhenStateSupplierIsNull() {
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assertThrows(NullPointerException.class,
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() -> Gatherers.<String, String>scan(null, (state, next) -> state));
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}
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@Test
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public void throwsNPEWhenScannerFunctionIsNull() {
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assertThrows(NullPointerException.class,
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() -> Gatherers.<String, String>scan(() -> "", null));
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}
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@ParameterizedTest
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@MethodSource("configurations")
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public void behavesAsExpected(Config config) {
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final List<Long> expectedResult;
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if (config.streamSize() == 0) {
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expectedResult = List.of();
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} else {
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expectedResult = config.stream()
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.sequential()
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.reduce(
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new LinkedList<Long>(),
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(acc, next) -> {
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acc.addLast((acc.isEmpty() ? 0L : acc.getLast()) + next);
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return acc;
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},
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(l, r) -> { throw new IllegalStateException(); }
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);
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}
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final var result = config.stream()
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.gather(Gatherers.scan(() -> 0L, (acc, next) -> acc + next))
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.toList();
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assertEquals(expectedResult, result);
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}
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}
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