/*
* 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);
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;
}
}