java.util.stream.IntStreamImpl Maven / Gradle / Ivy
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/*
* 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.HashSet;
import java.util.IntSummaryStatistics;
import java.util.OptionalDouble;
import java.util.OptionalInt;
import java.util.PrimitiveIterator;
import java.util.Spliterator;
import java.util.Spliterators;
import java.util.Spliterators.AbstractIntSpliterator;
import java.util.function.BiConsumer;
import java.util.function.Consumer;
import java.util.function.DoubleConsumer;
import java.util.function.IntBinaryOperator;
import java.util.function.IntConsumer;
import java.util.function.IntFunction;
import java.util.function.IntPredicate;
import java.util.function.IntToDoubleFunction;
import java.util.function.IntToLongFunction;
import java.util.function.IntUnaryOperator;
import java.util.function.LongConsumer;
import java.util.function.ObjIntConsumer;
import java.util.function.Supplier;
import javaemul.internal.PrimitiveLists;
/**
* Main implementation of IntStream, wrapping a single spliterator, and an optional parent stream.
*/
final class IntStreamImpl extends TerminatableStream implements IntStream {
/**
* Represents an empty stream, doing nothing for all methods.
*/
static class Empty extends TerminatableStream implements IntStream {
public Empty(TerminatableStream previous) {
super(previous);
}
@Override
public IntStream filter(IntPredicate predicate) {
throwIfTerminated();
return this;
}
@Override
public IntStream map(IntUnaryOperator mapper) {
throwIfTerminated();
return this;
}
@Override
public Stream mapToObj(IntFunction mapper) {
throwIfTerminated();
return new StreamImpl.Empty(this);
}
@Override
public LongStream mapToLong(IntToLongFunction mapper) {
throwIfTerminated();
return new LongStreamImpl.Empty(this);
}
@Override
public DoubleStream mapToDouble(IntToDoubleFunction mapper) {
throwIfTerminated();
return new DoubleStreamImpl.Empty(this);
}
@Override
public IntStream flatMap(IntFunction mapper) {
throwIfTerminated();
return this;
}
@Override
public IntStream distinct() {
throwIfTerminated();
return this;
}
@Override
public IntStream sorted() {
throwIfTerminated();
return this;
}
@Override
public IntStream peek(IntConsumer action) {
throwIfTerminated();
return this;
}
@Override
public IntStream limit(long maxSize) {
throwIfTerminated();
checkState(maxSize >= 0, "maxSize may not be negative");
return this;
}
@Override
public IntStream skip(long n) {
throwIfTerminated();
checkState(n >= 0, "n may not be negative");
return this;
}
@Override
public void forEach(IntConsumer action) {
terminate();
// do nothing
}
@Override
public void forEachOrdered(IntConsumer action) {
terminate();
// do nothing
}
@Override
public int[] toArray() {
terminate();
return new int[0];
}
@Override
public int reduce(int identity, IntBinaryOperator op) {
terminate();
return identity;
}
@Override
public OptionalInt reduce(IntBinaryOperator op) {
terminate();
return OptionalInt.empty();
}
@Override
public R collect(
Supplier supplier, ObjIntConsumer accumulator, BiConsumer combiner) {
terminate();
return supplier.get();
}
@Override
public int sum() {
terminate();
return 0;
}
@Override
public OptionalInt min() {
terminate();
return OptionalInt.empty();
}
@Override
public OptionalInt max() {
terminate();
return OptionalInt.empty();
}
@Override
public long count() {
terminate();
return 0;
}
@Override
public OptionalDouble average() {
terminate();
return OptionalDouble.empty();
}
@Override
public IntSummaryStatistics summaryStatistics() {
terminate();
return new IntSummaryStatistics();
}
@Override
public boolean anyMatch(IntPredicate predicate) {
terminate();
return false;
}
@Override
public boolean allMatch(IntPredicate predicate) {
terminate();
return true;
}
@Override
public boolean noneMatch(IntPredicate predicate) {
terminate();
return true;
}
@Override
public OptionalInt findFirst() {
terminate();
return OptionalInt.empty();
}
@Override
public OptionalInt findAny() {
terminate();
return OptionalInt.empty();
}
@Override
public LongStream asLongStream() {
throwIfTerminated();
return new LongStreamImpl.Empty(this);
}
@Override
public DoubleStream asDoubleStream() {
throwIfTerminated();
return new DoubleStreamImpl.Empty(this);
}
@Override
public Stream boxed() {
throwIfTerminated();
return new StreamImpl.Empty(this);
}
@Override
public IntStream sequential() {
throwIfTerminated();
return this;
}
@Override
public IntStream parallel() {
throwIfTerminated();
return this;
}
@Override
public PrimitiveIterator.OfInt iterator() {
return Spliterators.iterator(spliterator());
}
@Override
public Spliterator.OfInt spliterator() {
terminate();
return Spliterators.emptyIntSpliterator();
}
@Override
public boolean isParallel() {
throwIfTerminated();
return false;
}
@Override
public IntStream unordered() {
throwIfTerminated();
return this;
}
}
/**
* Int to Int map spliterator.
*/
private static final class MapToIntSpliterator extends Spliterators.AbstractIntSpliterator {
private final IntUnaryOperator map;
private final Spliterator.OfInt original;
public MapToIntSpliterator(IntUnaryOperator map, Spliterator.OfInt 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((int u) -> action.accept(map.applyAsInt(u)));
}
}
/**
* Int to Object map spliterator.
*
* @param the type of data in the object spliterator
*/
private static final class MapToObjSpliterator extends Spliterators.AbstractSpliterator {
private final IntFunction map;
private final Spliterator.OfInt original;
public MapToObjSpliterator(IntFunction map, Spliterator.OfInt original) {
super(
original.estimateSize(),
original.characteristics() & ~(Spliterator.SORTED | Spliterator.DISTINCT));
checkNotNull(map);
this.map = map;
this.original = original;
}
@Override
public boolean tryAdvance(final Consumer action) {
return original.tryAdvance((int u) -> action.accept(map.apply(u)));
}
}
/**
* Int to Long map spliterator.
*/
private static final class MapToLongSpliterator extends Spliterators.AbstractLongSpliterator {
private final IntToLongFunction map;
private final Spliterator.OfInt original;
public MapToLongSpliterator(IntToLongFunction map, Spliterator.OfInt 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((int u) -> action.accept(map.applyAsLong(u)));
}
}
/**
* Int to Double map spliterator.
*/
private static final class MapToDoubleSpliterator extends Spliterators.AbstractDoubleSpliterator {
private final IntToDoubleFunction map;
private final Spliterator.OfInt original;
public MapToDoubleSpliterator(IntToDoubleFunction map, Spliterator.OfInt 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((int u) -> action.accept(map.applyAsDouble(u)));
}
}
/**
* Int filter spliterator.
*/
private static final class FilterSpliterator extends Spliterators.AbstractIntSpliterator {
private final IntPredicate filter;
private final Spliterator.OfInt original;
private boolean found;
public FilterSpliterator(IntPredicate filter, Spliterator.OfInt original) {
super(
original.estimateSize(),
original.characteristics() & ~(Spliterator.SIZED | Spliterator.SUBSIZED));
checkNotNull(filter);
this.filter = filter;
this.original = original;
}
@Override
public Comparator getComparator() {
return original.getComparator();
}
@Override
public boolean tryAdvance(final IntConsumer action) {
found = false;
while (!found
&& original.tryAdvance(
(int item) -> {
if (filter.test(item)) {
found = true;
action.accept(item);
}
})) {
// do nothing, work is done in tryAdvance
}
return found;
}
}
/**
* Int skip spliterator.
*/
private static final class SkipSpliterator extends Spliterators.AbstractIntSpliterator {
private long skip;
private final Spliterator.OfInt original;
public SkipSpliterator(long skip, Spliterator.OfInt 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 getComparator() {
return original.getComparator();
}
@Override
public boolean tryAdvance(IntConsumer action) {
while (skip > 0) {
if (!original.tryAdvance((int ignore) -> { })) {
return false;
}
skip--;
}
return original.tryAdvance(action);
}
}
/**
* Int limit spliterator.
*/
private static final class LimitSpliterator extends Spliterators.AbstractIntSpliterator {
private final long limit;
private final Spliterator.OfInt original;
private int position = 0;
public LimitSpliterator(long limit, Spliterator.OfInt 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 getComparator() {
return original.getComparator();
}
@Override
public boolean tryAdvance(IntConsumer action) {
if (position >= limit) {
return false;
}
boolean result = original.tryAdvance(action);
position++;
return result;
}
}
/**
* Value holder for various stream operations.
*/
private static final class ValueConsumer implements IntConsumer {
int value;
@Override
public void accept(int value) {
this.value = value;
}
}
private final Spliterator.OfInt spliterator;
public IntStreamImpl(TerminatableStream previous, Spliterator.OfInt spliterator) {
super(previous);
this.spliterator = spliterator;
}
// terminals
@Override
public Spliterator.OfInt spliterator() {
terminate();
return spliterator;
}
@Override
public PrimitiveIterator.OfInt iterator() {
return Spliterators.iterator(spliterator());
}
@Override
public OptionalInt findFirst() {
terminate();
ValueConsumer holder = new ValueConsumer();
if (spliterator.tryAdvance(holder)) {
return OptionalInt.of(holder.value);
}
return OptionalInt.empty();
}
@Override
public OptionalInt findAny() {
return findFirst();
}
@Override
public boolean noneMatch(IntPredicate predicate) {
return !anyMatch(predicate);
}
@Override
public boolean allMatch(IntPredicate predicate) {
return !anyMatch(predicate.negate());
}
@Override
public boolean anyMatch(IntPredicate predicate) {
return filter(predicate).findFirst().isPresent();
}
@Override
public IntSummaryStatistics summaryStatistics() {
return collect(
IntSummaryStatistics::new,
// TODO switch to a lambda reference once #9340 is fixed
(intSummaryStatistics, value) -> intSummaryStatistics.accept(value),
IntSummaryStatistics::combine);
}
@Override
public OptionalDouble average() {
IntSummaryStatistics stats = summaryStatistics();
if (stats.getCount() == 0) {
return OptionalDouble.empty();
}
return OptionalDouble.of(stats.getAverage());
}
@Override
public long count() {
terminate();
long count = 0;
while (spliterator.tryAdvance((int value) -> { })) {
count++;
}
return count;
}
@Override
public OptionalInt max() {
IntSummaryStatistics stats = summaryStatistics();
if (stats.getCount() == 0) {
return OptionalInt.empty();
}
return OptionalInt.of(stats.getMax());
}
@Override
public OptionalInt min() {
IntSummaryStatistics stats = summaryStatistics();
if (stats.getCount() == 0) {
return OptionalInt.empty();
}
return OptionalInt.of(stats.getMin());
}
@Override
public int sum() {
return (int) summaryStatistics().getSum();
}
@Override
public R collect(
Supplier supplier, final ObjIntConsumer accumulator, BiConsumer combiner) {
terminate();
final R acc = supplier.get();
spliterator.forEachRemaining((int value) -> accumulator.accept(acc, value));
return acc;
}
@Override
public OptionalInt reduce(IntBinaryOperator op) {
ValueConsumer holder = new ValueConsumer();
if (spliterator.tryAdvance(holder)) {
return OptionalInt.of(reduce(holder.value, op));
}
terminate();
return OptionalInt.empty();
}
@Override
public int reduce(int identity, IntBinaryOperator op) {
terminate();
ValueConsumer holder = new ValueConsumer();
holder.value = identity;
spliterator.forEachRemaining(
(int value) -> {
holder.accept(op.applyAsInt(holder.value, value));
});
return holder.value;
}
@Override
public int[] toArray() {
terminate();
PrimitiveLists.Int entries = PrimitiveLists.createForInt();
spliterator.forEachRemaining((int value) -> entries.push(value));
return entries.toArray();
}
@Override
public void forEachOrdered(IntConsumer action) {
terminate();
spliterator.forEachRemaining(action);
}
@Override
public void forEach(IntConsumer action) {
forEachOrdered(action);
}
// end terminals
// intermediates
@Override
public IntStream filter(IntPredicate predicate) {
throwIfTerminated();
return new IntStreamImpl(this, new FilterSpliterator(predicate, spliterator));
}
@Override
public IntStream map(IntUnaryOperator mapper) {
throwIfTerminated();
return new IntStreamImpl(this, new MapToIntSpliterator(mapper, spliterator));
}
@Override
public Stream mapToObj(IntFunction mapper) {
throwIfTerminated();
return new StreamImpl(this, new MapToObjSpliterator(mapper, spliterator));
}
@Override
public LongStream mapToLong(IntToLongFunction mapper) {
throwIfTerminated();
return new LongStreamImpl(this, new MapToLongSpliterator(mapper, spliterator));
}
@Override
public DoubleStream mapToDouble(IntToDoubleFunction mapper) {
throwIfTerminated();
return new DoubleStreamImpl(this, new MapToDoubleSpliterator(mapper, spliterator));
}
@Override
public IntStream flatMap(IntFunction mapper) {
throwIfTerminated();
final Spliterator spliteratorOfStreams =
new MapToObjSpliterator<>(mapper, spliterator);
Spliterator.OfInt flatMapSpliterator =
new Spliterators.AbstractIntSpliterator(Long.MAX_VALUE, 0) {
IntStream nextStream;
Spliterator.OfInt next;
@Override
public boolean tryAdvance(IntConsumer 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 IntStreamImpl(this, flatMapSpliterator);
}
@Override
public IntStream distinct() {
throwIfTerminated();
HashSet seen = new HashSet<>();
return filter(seen::add);
}
@Override
public IntStream sorted() {
throwIfTerminated();
AbstractIntSpliterator sortedSpliterator =
new Spliterators.AbstractIntSpliterator(
spliterator.estimateSize(), spliterator.characteristics() | Spliterator.SORTED) {
Spliterator.OfInt ordered = null;
@Override
public Comparator getComparator() {
return null;
}
@Override
public boolean tryAdvance(IntConsumer action) {
if (ordered == null) {
PrimitiveLists.Int list = PrimitiveLists.createForInt();
spliterator.forEachRemaining((int value) -> list.push(value));
Arrays.sort(list.internalArray(), 0, list.size());
ordered =
Spliterators.spliterator(list.internalArray(), 0, list.size(), characteristics());
}
return ordered.tryAdvance(action);
}
};
return new IntStreamImpl(this, sortedSpliterator);
}
@Override
public IntStream peek(IntConsumer action) {
checkNotNull(action);
throwIfTerminated();
AbstractIntSpliterator peekSpliterator =
new Spliterators.AbstractIntSpliterator(
spliterator.estimateSize(), spliterator.characteristics()) {
@Override
public boolean tryAdvance(final IntConsumer innerAction) {
return spliterator.tryAdvance(action.andThen(innerAction));
}
};
return new IntStreamImpl(this, peekSpliterator);
}
@Override
public IntStream limit(long maxSize) {
throwIfTerminated();
checkState(maxSize >= 0, "maxSize may not be negative");
return new IntStreamImpl(this, new LimitSpliterator(maxSize, spliterator));
}
@Override
public IntStream skip(long n) {
throwIfTerminated();
checkState(n >= 0, "n may not be negative");
if (n == 0) {
return this;
}
return new IntStreamImpl(this, new SkipSpliterator(n, spliterator));
}
@Override
public LongStream asLongStream() {
return mapToLong(i -> (long) i);
}
@Override
public DoubleStream asDoubleStream() {
return mapToDouble(i -> (double) i);
}
@Override
public Stream boxed() {
return mapToObj(Integer::valueOf);
}
@Override
public IntStream sequential() {
throwIfTerminated();
return this;
}
@Override
public IntStream parallel() {
throwIfTerminated();
return this;
}
@Override
public boolean isParallel() {
throwIfTerminated();
return false;
}
@Override
public IntStream unordered() {
throwIfTerminated();
return this;
}
}