| /* |
| * Copyright 2016 Google Inc. |
| * |
| * 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 java.util.stream; |
| |
| import static javaemul.internal.InternalPreconditions.checkNotNull; |
| import static javaemul.internal.InternalPreconditions.checkState; |
| |
| import java.util.Arrays; |
| import java.util.Comparator; |
| import java.util.DoubleSummaryStatistics; |
| import java.util.HashSet; |
| import java.util.OptionalDouble; |
| import java.util.PrimitiveIterator; |
| import java.util.Spliterator; |
| import java.util.Spliterators; |
| import java.util.function.BiConsumer; |
| import java.util.function.Consumer; |
| import java.util.function.DoubleBinaryOperator; |
| import java.util.function.DoubleConsumer; |
| import java.util.function.DoubleFunction; |
| import java.util.function.DoublePredicate; |
| import java.util.function.DoubleToIntFunction; |
| import java.util.function.DoubleToLongFunction; |
| import java.util.function.DoubleUnaryOperator; |
| import java.util.function.IntConsumer; |
| import java.util.function.LongConsumer; |
| import java.util.function.ObjDoubleConsumer; |
| import java.util.function.Supplier; |
| |
| /** |
| * Main implementation of DoubleStream, wrapping a single spliterator, and an optional parent |
| * stream. |
| */ |
| final class DoubleStreamImpl extends TerminatableStream<DoubleStreamImpl> implements DoubleStream { |
| |
| /** |
| * Represents an empty stream, doing nothing for all methods. |
| */ |
| static class Empty extends TerminatableStream<Empty> implements DoubleStream { |
| public Empty(TerminatableStream<?> previous) { |
| super(previous); |
| } |
| |
| @Override |
| public DoubleStream filter(DoublePredicate predicate) { |
| throwIfTerminated(); |
| return this; |
| } |
| |
| @Override |
| public DoubleStream map(DoubleUnaryOperator mapper) { |
| throwIfTerminated(); |
| return this; |
| } |
| |
| @Override |
| public <U> Stream<U> mapToObj(DoubleFunction<? extends U> mapper) { |
| throwIfTerminated(); |
| return new StreamImpl.Empty<U>(this); |
| } |
| |
| @Override |
| public IntStream mapToInt(DoubleToIntFunction mapper) { |
| throwIfTerminated(); |
| return new IntStreamImpl.Empty(this); |
| } |
| |
| @Override |
| public LongStream mapToLong(DoubleToLongFunction mapper) { |
| throwIfTerminated(); |
| return new LongStreamImpl.Empty(this); |
| } |
| |
| @Override |
| public DoubleStream flatMap(DoubleFunction<? extends DoubleStream> mapper) { |
| throwIfTerminated(); |
| return this; |
| } |
| |
| @Override |
| public DoubleStream distinct() { |
| throwIfTerminated(); |
| return this; |
| } |
| |
| @Override |
| public DoubleStream sorted() { |
| throwIfTerminated(); |
| return this; |
| } |
| |
| @Override |
| public DoubleStream peek(DoubleConsumer action) { |
| throwIfTerminated(); |
| return this; |
| } |
| |
| @Override |
| public DoubleStream limit(long maxSize) { |
| throwIfTerminated(); |
| checkState(maxSize >= 0, "maxSize may not be negative"); |
| return this; |
| } |
| |
| @Override |
| public DoubleStream skip(long n) { |
| throwIfTerminated(); |
| checkState(n >= 0, "n may not be negative"); |
| return this; |
| } |
| |
| @Override |
| public void forEach(DoubleConsumer action) { |
| terminate(); |
| // do nothing |
| } |
| |
| @Override |
| public void forEachOrdered(DoubleConsumer action) { |
| terminate(); |
| // do nothing |
| } |
| |
| @Override |
| public double[] toArray() { |
| terminate(); |
| return new double[0]; |
| } |
| |
| @Override |
| public double reduce(double identity, DoubleBinaryOperator op) { |
| terminate(); |
| return identity; |
| } |
| |
| @Override |
| public OptionalDouble reduce(DoubleBinaryOperator op) { |
| terminate(); |
| return OptionalDouble.empty(); |
| } |
| |
| @Override |
| public <R> R collect( |
| Supplier<R> supplier, ObjDoubleConsumer<R> accumulator, BiConsumer<R, R> combiner) { |
| terminate(); |
| return supplier.get(); |
| } |
| |
| @Override |
| public double sum() { |
| terminate(); |
| return 0; |
| } |
| |
| @Override |
| public OptionalDouble min() { |
| terminate(); |
| return OptionalDouble.empty(); |
| } |
| |
| @Override |
| public OptionalDouble max() { |
| terminate(); |
| return OptionalDouble.empty(); |
| } |
| |
| @Override |
| public long count() { |
| terminate(); |
| return 0; |
| } |
| |
| @Override |
| public OptionalDouble average() { |
| terminate(); |
| return OptionalDouble.empty(); |
| } |
| |
| @Override |
| public DoubleSummaryStatistics summaryStatistics() { |
| terminate(); |
| return new DoubleSummaryStatistics(); |
| } |
| |
| @Override |
| public boolean anyMatch(DoublePredicate predicate) { |
| terminate(); |
| return false; |
| } |
| |
| @Override |
| public boolean allMatch(DoublePredicate predicate) { |
| terminate(); |
| return true; |
| } |
| |
| @Override |
| public boolean noneMatch(DoublePredicate predicate) { |
| terminate(); |
| return true; |
| } |
| |
| @Override |
| public OptionalDouble findFirst() { |
| terminate(); |
| return OptionalDouble.empty(); |
| } |
| |
| @Override |
| public OptionalDouble findAny() { |
| terminate(); |
| return OptionalDouble.empty(); |
| } |
| |
| @Override |
| public Stream<Double> boxed() { |
| throwIfTerminated(); |
| return new StreamImpl.Empty<Double>(this); |
| } |
| |
| @Override |
| public DoubleStream sequential() { |
| throwIfTerminated(); |
| return this; |
| } |
| |
| @Override |
| public DoubleStream parallel() { |
| throwIfTerminated(); |
| return this; |
| } |
| |
| @Override |
| public PrimitiveIterator.OfDouble iterator() { |
| return Spliterators.iterator(spliterator()); |
| } |
| |
| @Override |
| public Spliterator.OfDouble spliterator() { |
| terminate(); |
| return Spliterators.emptyDoubleSpliterator(); |
| } |
| |
| @Override |
| public boolean isParallel() { |
| throwIfTerminated(); |
| return false; |
| } |
| |
| @Override |
| public DoubleStream unordered() { |
| throwIfTerminated(); |
| return this; |
| } |
| } |
| |
| /** |
| * Double to Int map spliterator. |
| */ |
| private static final class MapToIntSpliterator extends Spliterators.AbstractIntSpliterator { |
| private final DoubleToIntFunction map; |
| private final Spliterator.OfDouble original; |
| |
| public MapToIntSpliterator(DoubleToIntFunction map, Spliterator.OfDouble original) { |
| super( |
| original.estimateSize(), |
| original.characteristics() & ~(Spliterator.SORTED | Spliterator.DISTINCT)); |
| checkNotNull(map); |
| this.map = map; |
| this.original = original; |
| } |
| |
| @Override |
| public boolean tryAdvance(final IntConsumer action) { |
| return original.tryAdvance((double u) -> action.accept(map.applyAsInt(u))); |
| } |
| } |
| |
| /** |
| * Double to Object map spliterator. |
| * |
| * @param <T> the type of Object in the spliterator |
| */ |
| private static final class MapToObjSpliterator<T> extends Spliterators.AbstractSpliterator<T> { |
| private final DoubleFunction<? extends T> map; |
| private final Spliterator.OfDouble original; |
| |
| public MapToObjSpliterator(DoubleFunction<? extends T> map, Spliterator.OfDouble original) { |
| super( |
| original.estimateSize(), |
| original.characteristics() & ~(Spliterator.SORTED | Spliterator.DISTINCT)); |
| checkNotNull(map); |
| this.map = map; |
| this.original = original; |
| } |
| |
| @Override |
| public boolean tryAdvance(final Consumer<? super T> action) { |
| return original.tryAdvance((double u) -> action.accept(map.apply(u))); |
| } |
| } |
| |
| /** |
| * Double to Long map spliterator. |
| */ |
| private static final class MapToLongSpliterator extends Spliterators.AbstractLongSpliterator { |
| private final DoubleToLongFunction map; |
| private final Spliterator.OfDouble original; |
| |
| public MapToLongSpliterator(DoubleToLongFunction map, Spliterator.OfDouble original) { |
| super( |
| original.estimateSize(), |
| original.characteristics() & ~(Spliterator.SORTED | Spliterator.DISTINCT)); |
| checkNotNull(map); |
| this.map = map; |
| this.original = original; |
| } |
| |
| @Override |
| public boolean tryAdvance(final LongConsumer action) { |
| return original.tryAdvance((double u) -> action.accept(map.applyAsLong(u))); |
| } |
| } |
| |
| /** |
| * Double to Double map spliterator. |
| */ |
| private static final class MapToDoubleSpliterator extends Spliterators.AbstractDoubleSpliterator { |
| private final DoubleUnaryOperator map; |
| private final Spliterator.OfDouble original; |
| |
| public MapToDoubleSpliterator(DoubleUnaryOperator map, Spliterator.OfDouble original) { |
| super( |
| original.estimateSize(), |
| original.characteristics() & ~(Spliterator.SORTED | Spliterator.DISTINCT)); |
| checkNotNull(map); |
| this.map = map; |
| this.original = original; |
| } |
| |
| @Override |
| public boolean tryAdvance(final DoubleConsumer action) { |
| return original.tryAdvance((double u) -> action.accept(map.applyAsDouble(u))); |
| } |
| } |
| |
| /** |
| * Double filter spliterator. |
| */ |
| private static final class FilterSpliterator extends Spliterators.AbstractDoubleSpliterator { |
| private final DoublePredicate filter; |
| private final Spliterator.OfDouble original; |
| |
| private boolean found; |
| |
| public FilterSpliterator(DoublePredicate filter, Spliterator.OfDouble original) { |
| super( |
| original.estimateSize(), |
| original.characteristics() & ~(Spliterator.SIZED | Spliterator.SUBSIZED)); |
| checkNotNull(filter); |
| this.filter = filter; |
| this.original = original; |
| } |
| |
| @Override |
| public Comparator<? super Double> getComparator() { |
| return original.getComparator(); |
| } |
| |
| @Override |
| public boolean tryAdvance(final DoubleConsumer action) { |
| found = false; |
| while (!found |
| && original.tryAdvance( |
| (double item) -> { |
| if (filter.test(item)) { |
| found = true; |
| action.accept(item); |
| } |
| })) { |
| // do nothing, work is done in tryAdvance |
| } |
| |
| return found; |
| } |
| } |
| |
| /** |
| * Double skip spliterator. |
| */ |
| private static final class SkipSpliterator extends Spliterators.AbstractDoubleSpliterator { |
| private long skip; |
| private final Spliterator.OfDouble original; |
| |
| public SkipSpliterator(long skip, Spliterator.OfDouble original) { |
| super( |
| original.hasCharacteristics(Spliterator.SIZED) |
| ? Math.max(0, original.estimateSize() - skip) |
| : Long.MAX_VALUE, |
| original.characteristics()); |
| this.skip = skip; |
| this.original = original; |
| } |
| |
| @Override |
| public Comparator<? super Double> getComparator() { |
| return original.getComparator(); |
| } |
| |
| @Override |
| public boolean tryAdvance(DoubleConsumer action) { |
| while (skip > 0) { |
| if (!original.tryAdvance((double ignore) -> { })) { |
| return false; |
| } |
| skip--; |
| } |
| return original.tryAdvance(action); |
| } |
| } |
| |
| /** |
| * Double limit spliterator. |
| */ |
| private static final class LimitSpliterator extends Spliterators.AbstractDoubleSpliterator { |
| private final long limit; |
| private final Spliterator.OfDouble original; |
| private int position = 0; |
| |
| public LimitSpliterator(long limit, Spliterator.OfDouble original) { |
| super( |
| original.hasCharacteristics(Spliterator.SIZED) |
| ? Math.min(original.estimateSize(), limit) |
| : Long.MAX_VALUE, |
| original.characteristics()); |
| this.limit = limit; |
| this.original = original; |
| } |
| |
| @Override |
| public Comparator<? super Double> getComparator() { |
| return original.getComparator(); |
| } |
| |
| @Override |
| public boolean tryAdvance(DoubleConsumer action) { |
| if (position >= limit) { |
| return false; |
| } |
| |
| boolean result = original.tryAdvance(action); |
| position++; |
| return result; |
| } |
| } |
| |
| /** |
| * Value holder for various stream operations. |
| */ |
| private static class ValueConsumer implements DoubleConsumer { |
| double value; |
| |
| @Override |
| public void accept(double value) { |
| this.value = value; |
| } |
| } |
| |
| private final Spliterator.OfDouble spliterator; |
| |
| public DoubleStreamImpl(TerminatableStream<?> previous, Spliterator.OfDouble spliterator) { |
| super(previous); |
| this.spliterator = spliterator; |
| } |
| |
| // terminals |
| |
| @Override |
| public void forEach(DoubleConsumer action) { |
| forEachOrdered(action); |
| } |
| |
| @Override |
| public void forEachOrdered(DoubleConsumer action) { |
| terminate(); |
| spliterator.forEachRemaining(action); |
| } |
| |
| @Override |
| public double[] toArray() { |
| terminate(); |
| double[] entries = new double[0]; |
| // this is legal in js, since the array will be backed by a JS array |
| spliterator.forEachRemaining((double value) -> entries[entries.length] = value); |
| |
| return entries; |
| } |
| |
| @Override |
| public double reduce(double identity, DoubleBinaryOperator op) { |
| terminate(); |
| ValueConsumer holder = new ValueConsumer(); |
| holder.value = identity; |
| spliterator.forEachRemaining( |
| (double value) -> { |
| holder.accept(op.applyAsDouble(holder.value, value)); |
| }); |
| return holder.value; |
| } |
| |
| @Override |
| public OptionalDouble reduce(DoubleBinaryOperator op) { |
| ValueConsumer holder = new ValueConsumer(); |
| if (spliterator.tryAdvance(holder)) { |
| return OptionalDouble.of(reduce(holder.value, op)); |
| } |
| terminate(); |
| return OptionalDouble.empty(); |
| } |
| |
| @Override |
| public <R> R collect( |
| Supplier<R> supplier, ObjDoubleConsumer<R> accumulator, BiConsumer<R, R> combiner) { |
| terminate(); |
| final R acc = supplier.get(); |
| spliterator.forEachRemaining((double value) -> accumulator.accept(acc, value)); |
| return acc; |
| } |
| |
| @Override |
| public double sum() { |
| return summaryStatistics().getSum(); |
| } |
| |
| @Override |
| public OptionalDouble min() { |
| DoubleSummaryStatistics stats = summaryStatistics(); |
| if (stats.getCount() == 0) { |
| return OptionalDouble.empty(); |
| } |
| return OptionalDouble.of(stats.getMin()); |
| } |
| |
| @Override |
| public OptionalDouble max() { |
| DoubleSummaryStatistics stats = summaryStatistics(); |
| if (stats.getCount() == 0) { |
| return OptionalDouble.empty(); |
| } |
| return OptionalDouble.of(stats.getMax()); |
| } |
| |
| @Override |
| public long count() { |
| terminate(); |
| long count = 0; |
| while (spliterator.tryAdvance((double value) -> { })) { |
| count++; |
| } |
| return count; |
| } |
| |
| @Override |
| public OptionalDouble average() { |
| DoubleSummaryStatistics stats = summaryStatistics(); |
| if (stats.getCount() == 0) { |
| return OptionalDouble.empty(); |
| } |
| return OptionalDouble.of(stats.getAverage()); |
| } |
| |
| @Override |
| public DoubleSummaryStatistics summaryStatistics() { |
| return collect( |
| DoubleSummaryStatistics::new, |
| // TODO switch to a lambda reference once #9340 is fixed |
| (doubleSummaryStatistics, value) -> doubleSummaryStatistics.accept(value), |
| DoubleSummaryStatistics::combine); |
| } |
| |
| @Override |
| public boolean anyMatch(DoublePredicate predicate) { |
| return filter(predicate).findFirst().isPresent(); |
| } |
| |
| @Override |
| public boolean allMatch(DoublePredicate predicate) { |
| return !anyMatch(predicate.negate()); |
| } |
| |
| @Override |
| public boolean noneMatch(DoublePredicate predicate) { |
| return !anyMatch(predicate); |
| } |
| |
| @Override |
| public OptionalDouble findFirst() { |
| terminate(); |
| ValueConsumer holder = new ValueConsumer(); |
| if (spliterator.tryAdvance(holder)) { |
| return OptionalDouble.of(holder.value); |
| } |
| return OptionalDouble.empty(); |
| } |
| |
| @Override |
| public OptionalDouble findAny() { |
| return findFirst(); |
| } |
| |
| @Override |
| public PrimitiveIterator.OfDouble iterator() { |
| return Spliterators.iterator(spliterator()); |
| } |
| |
| @Override |
| public Spliterator.OfDouble spliterator() { |
| terminate(); |
| return spliterator; |
| } |
| |
| // end terminals |
| |
| // intermediates |
| |
| @Override |
| public DoubleStream filter(DoublePredicate predicate) { |
| throwIfTerminated(); |
| return new DoubleStreamImpl(this, new FilterSpliterator(predicate, spliterator)); |
| } |
| |
| @Override |
| public DoubleStream map(DoubleUnaryOperator mapper) { |
| throwIfTerminated(); |
| return new DoubleStreamImpl(this, new MapToDoubleSpliterator(mapper, spliterator)); |
| } |
| |
| @Override |
| public <U> Stream<U> mapToObj(DoubleFunction<? extends U> mapper) { |
| throwIfTerminated(); |
| return new StreamImpl<U>(this, new MapToObjSpliterator<U>(mapper, spliterator)); |
| } |
| |
| @Override |
| public IntStream mapToInt(DoubleToIntFunction mapper) { |
| throwIfTerminated(); |
| return new IntStreamImpl(this, new MapToIntSpliterator(mapper, spliterator)); |
| } |
| |
| @Override |
| public LongStream mapToLong(DoubleToLongFunction mapper) { |
| throwIfTerminated(); |
| return new LongStreamImpl(this, new MapToLongSpliterator(mapper, spliterator)); |
| } |
| |
| @Override |
| public DoubleStream flatMap(DoubleFunction<? extends DoubleStream> mapper) { |
| throwIfTerminated(); |
| final Spliterator<? extends DoubleStream> spliteratorOfStreams = |
| new MapToObjSpliterator<DoubleStream>(mapper, spliterator); |
| |
| Spliterator.OfDouble flatMapSpliterator = |
| new Spliterators.AbstractDoubleSpliterator(Long.MAX_VALUE, 0) { |
| DoubleStream nextStream; |
| Spliterator.OfDouble next; |
| |
| @Override |
| public boolean tryAdvance(DoubleConsumer action) { |
| // look for a new spliterator |
| while (advanceToNextSpliterator()) { |
| // if we have one, try to read and use it |
| if (next.tryAdvance(action)) { |
| return true; |
| } else { |
| nextStream.close(); |
| nextStream = null; |
| // failed, null it out so we can find another |
| next = null; |
| } |
| } |
| return false; |
| } |
| |
| private boolean advanceToNextSpliterator() { |
| while (next == null) { |
| if (!spliteratorOfStreams.tryAdvance( |
| n -> { |
| if (n != null) { |
| nextStream = n; |
| next = n.spliterator(); |
| } |
| })) { |
| return false; |
| } |
| } |
| return true; |
| } |
| }; |
| |
| return new DoubleStreamImpl(this, flatMapSpliterator); |
| } |
| |
| @Override |
| public DoubleStream distinct() { |
| throwIfTerminated(); |
| HashSet<Double> seen = new HashSet<>(); |
| return filter(seen::add); |
| } |
| |
| @Override |
| public DoubleStream sorted() { |
| throwIfTerminated(); |
| |
| Spliterator.OfDouble sortingSpliterator = |
| new Spliterators.AbstractDoubleSpliterator( |
| spliterator.estimateSize(), spliterator.characteristics() | Spliterator.SORTED) { |
| Spliterator.OfDouble ordered = null; |
| |
| @Override |
| public Comparator<? super Double> getComparator() { |
| return null; |
| } |
| |
| @Override |
| public boolean tryAdvance(DoubleConsumer action) { |
| if (ordered == null) { |
| double[] list = new double[0]; |
| spliterator.forEachRemaining((double item) -> list[list.length] = item); |
| Arrays.sort(list); |
| ordered = Spliterators.spliterator(list, characteristics()); |
| } |
| return ordered.tryAdvance(action); |
| } |
| }; |
| |
| return new DoubleStreamImpl(this, sortingSpliterator); |
| } |
| |
| @Override |
| public DoubleStream peek(DoubleConsumer action) { |
| checkNotNull(action); |
| throwIfTerminated(); |
| |
| Spliterator.OfDouble peekSpliterator = |
| new Spliterators.AbstractDoubleSpliterator( |
| spliterator.estimateSize(), spliterator.characteristics()) { |
| @Override |
| public boolean tryAdvance(final DoubleConsumer innerAction) { |
| return spliterator.tryAdvance(action.andThen(innerAction)); |
| } |
| }; |
| |
| return new DoubleStreamImpl(this, peekSpliterator); |
| } |
| |
| @Override |
| public DoubleStream limit(long maxSize) { |
| throwIfTerminated(); |
| checkState(maxSize >= 0, "maxSize may not be negative"); |
| return new DoubleStreamImpl(this, new LimitSpliterator(maxSize, spliterator)); |
| } |
| |
| @Override |
| public DoubleStream skip(long n) { |
| throwIfTerminated(); |
| checkState(n >= 0, "n may not be negative"); |
| if (n == 0) { |
| return this; |
| } |
| return new DoubleStreamImpl(this, new SkipSpliterator(n, spliterator)); |
| } |
| |
| @Override |
| public Stream<Double> boxed() { |
| return mapToObj(Double::valueOf); |
| } |
| |
| @Override |
| public DoubleStream sequential() { |
| throwIfTerminated(); |
| return this; |
| } |
| |
| @Override |
| public DoubleStream parallel() { |
| throwIfTerminated(); |
| return this; |
| } |
| |
| @Override |
| public boolean isParallel() { |
| throwIfTerminated(); |
| return false; |
| } |
| |
| @Override |
| public DoubleStream unordered() { |
| throwIfTerminated(); |
| return this; |
| } |
| } |