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/*
* Copyright (C) 2015 The Guava Authors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.google.common.collect.testing;
import static com.google.common.base.Preconditions.checkNotNull;
import static com.google.common.collect.testing.Helpers.assertEqualIgnoringOrder;
import static com.google.common.collect.testing.Helpers.assertEqualInOrder;
import static com.google.common.collect.testing.Platform.format;
import static junit.framework.Assert.assertEquals;
import static junit.framework.Assert.assertFalse;
import static junit.framework.Assert.assertTrue;
import static junit.framework.Assert.fail;
import com.google.common.annotations.GwtCompatible;
import com.google.common.collect.Ordering;
import com.google.common.primitives.Ints;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Comparator;
import java.util.EnumSet;
import java.util.List;
import java.util.Spliterator;
import java.util.function.Consumer;
import java.util.function.Supplier;
import org.checkerframework.checker.nullness.qual.Nullable;
/** Tester for {@code Spliterator} implementations. */
@GwtCompatible
public final class SpliteratorTester<E> {
/** Return type from "contains the following elements" assertions. */
public interface Ordered {
/**
* Attests that the expected values must not just be present but must be present in the order
* they were given.
*/
void inOrder();
}
/**
* Different ways of decomposing a Spliterator, all of which must produce the same elements (up to
* ordering, if Spliterator.ORDERED is not present).
*/
enum SpliteratorDecompositionStrategy {
NO_SPLIT_FOR_EACH_REMAINING {
@Override
<E> void forEach(Spliterator<E> spliterator, Consumer<? super E> consumer) {
spliterator.forEachRemaining(consumer);
}
},
NO_SPLIT_TRY_ADVANCE {
@Override
<E> void forEach(Spliterator<E> spliterator, Consumer<? super E> consumer) {
while (spliterator.tryAdvance(consumer)) {
// do nothing
}
}
},
MAXIMUM_SPLIT {
@Override
<E> void forEach(Spliterator<E> spliterator, Consumer<? super E> consumer) {
for (Spliterator<E> prefix = trySplitTestingSize(spliterator);
prefix != null;
prefix = trySplitTestingSize(spliterator)) {
forEach(prefix, consumer);
}
long size = spliterator.getExactSizeIfKnown();
long[] counter = {0};
spliterator.forEachRemaining(
e -> {
consumer.accept(e);
counter[0]++;
});
if (size >= 0) {
assertEquals(size, counter[0]);
}
}
},
ALTERNATE_ADVANCE_AND_SPLIT {
@Override
<E> void forEach(Spliterator<E> spliterator, Consumer<? super E> consumer) {
while (spliterator.tryAdvance(consumer)) {
Spliterator<E> prefix = trySplitTestingSize(spliterator);
if (prefix != null) {
forEach(prefix, consumer);
}
}
}
};
abstract <E> void forEach(Spliterator<E> spliterator, Consumer<? super E> consumer);
}
@Nullable
private static <E> Spliterator<E> trySplitTestingSize(Spliterator<E> spliterator) {
boolean subsized = spliterator.hasCharacteristics(Spliterator.SUBSIZED);
long originalSize = spliterator.estimateSize();
Spliterator<E> trySplit = spliterator.trySplit();
if (spliterator.estimateSize() > originalSize) {
fail(
format(
"estimated size of spliterator after trySplit (%s) is larger than original size (%s)",
spliterator.estimateSize(), originalSize));
}
if (trySplit != null) {
if (trySplit.estimateSize() > originalSize) {
fail(
format(
"estimated size of trySplit result (%s) is larger than original size (%s)",
trySplit.estimateSize(), originalSize));
}
}
if (subsized) {
if (trySplit != null) {
assertEquals(
"sum of estimated sizes of trySplit and original spliterator after trySplit",
originalSize,
trySplit.estimateSize() + spliterator.estimateSize());
} else {
assertEquals(
"estimated size of spliterator after failed trySplit",
originalSize,
spliterator.estimateSize());
}
}
return trySplit;
}
public static <E> SpliteratorTester<E> of(Supplier<Spliterator<E>> spliteratorSupplier) {
return new SpliteratorTester<E>(spliteratorSupplier);
}
private final Supplier<Spliterator<E>> spliteratorSupplier;
private SpliteratorTester(Supplier<Spliterator<E>> spliteratorSupplier) {
this.spliteratorSupplier = checkNotNull(spliteratorSupplier);
}
@SafeVarargs
public final Ordered expect(Object... elements) {
return expect(Arrays.asList(elements));
}
public final Ordered expect(Iterable<?> elements) {
List<List<E>> resultsForAllStrategies = new ArrayList<>();
Spliterator<E> spliterator = spliteratorSupplier.get();
int characteristics = spliterator.characteristics();
long estimatedSize = spliterator.estimateSize();
for (SpliteratorDecompositionStrategy strategy :
EnumSet.allOf(SpliteratorDecompositionStrategy.class)) {
List<E> resultsForStrategy = new ArrayList<>();
strategy.forEach(spliteratorSupplier.get(), resultsForStrategy::add);
// TODO(cpovirk): better failure messages
if ((characteristics & Spliterator.NONNULL) != 0) {
assertFalse(resultsForStrategy.contains(null));
}
if ((characteristics & Spliterator.SORTED) != 0) {
Comparator<? super E> comparator = spliterator.getComparator();
if (comparator == null) {
comparator = (Comparator) Comparator.naturalOrder();
}
assertTrue(Ordering.from(comparator).isOrdered(resultsForStrategy));
}
if ((characteristics & Spliterator.SIZED) != 0) {
assertEquals(Ints.checkedCast(estimatedSize), resultsForStrategy.size());
}
assertEqualIgnoringOrder(elements, resultsForStrategy);
resultsForAllStrategies.add(resultsForStrategy);
}
return new Ordered() {
@Override
public void inOrder() {
resultsForAllStrategies.forEach(
resultsForStrategy -> assertEqualInOrder(elements, resultsForStrategy));
}
};
}
}
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