/*
* Copyright (c) 2012, 2013, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
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package java.util.stream;
import java.util.Comparator;
import java.util.Iterator;
import java.util.Objects;
import java.util.Optional;
import java.util.Spliterator;
import java.util.Spliterators;
import java.util.function.BiConsumer;
import java.util.function.BiFunction;
import java.util.function.BinaryOperator;
import java.util.function.Consumer;
import java.util.function.DoubleConsumer;
import java.util.function.Function;
import java.util.function.IntConsumer;
import java.util.function.IntFunction;
import java.util.function.LongConsumer;
import java.util.function.Predicate;
import java.util.function.Supplier;
import java.util.function.ToDoubleFunction;
import java.util.function.ToIntFunction;
import java.util.function.ToLongFunction;
/**
* Abstract base class for an intermediate pipeline stage or pipeline source
* stage implementing whose elements are of type {@code U}.
*
* @param <P_IN> type of elements in the upstream source
* @param <P_OUT> type of elements in produced by this stage
*
* @since 1.8
*/
abstract class ReferencePipeline<P_IN, P_OUT>
extends AbstractPipeline<P_IN, P_OUT, Stream<P_OUT>>
implements Stream<P_OUT> {
/**
* Constructor for the head of a stream pipeline.
*
* @param source {@code Supplier<Spliterator>} describing the stream source
* @param sourceFlags the source flags for the stream source, described in
* {@link StreamOpFlag}
* @param parallel {@code true} if the pipeline is parallel
*/
ReferencePipeline(Supplier<? extends Spliterator<?>> source,
int sourceFlags, boolean parallel) {
super(source, sourceFlags, parallel);
}
/**
* Constructor for the head of a stream pipeline.
*
* @param source {@code Spliterator} describing the stream source
* @param sourceFlags The source flags for the stream source, described in
* {@link StreamOpFlag}
* @param parallel {@code true} if the pipeline is parallel
*/
ReferencePipeline(Spliterator<?> source,
int sourceFlags, boolean parallel) {
super(source, sourceFlags, parallel);
}
/**
* Constructor for appending an intermediate operation onto an existing
* pipeline.
*
* @param upstream the upstream element source.
*/
ReferencePipeline(AbstractPipeline<?, P_IN, ?> upstream, int opFlags) {
super(upstream, opFlags);
}
// Shape-specific methods
@Override
final StreamShape getOutputShape() {
return StreamShape.REFERENCE;
}
@Override
final <P_IN> Node<P_OUT> evaluateToNode(PipelineHelper<P_OUT> helper,
Spliterator<P_IN> spliterator,
boolean flattenTree,
IntFunction<P_OUT[]> generator) {
return Nodes.collect(helper, spliterator, flattenTree, generator);
}
@Override
final <P_IN> Spliterator<P_OUT> wrap(PipelineHelper<P_OUT> ph,
Supplier<Spliterator<P_IN>> supplier,
boolean isParallel) {
return new StreamSpliterators.WrappingSpliterator<>(ph, supplier, isParallel);
}
@Override
final Spliterator<P_OUT> lazySpliterator(Supplier<? extends Spliterator<P_OUT>> supplier) {
return new StreamSpliterators.DelegatingSpliterator<>(supplier);
}
@Override
final void forEachWithCancel(Spliterator<P_OUT> spliterator, Sink<P_OUT> sink) {
do { } while (!sink.cancellationRequested() && spliterator.tryAdvance(sink));
}
@Override
final Node.Builder<P_OUT> makeNodeBuilder(long exactSizeIfKnown, IntFunction<P_OUT[]> generator) {
return Nodes.builder(exactSizeIfKnown, generator);
}
// BaseStream
@Override
public final Iterator<P_OUT> iterator() {
return Spliterators.iterator(spliterator());
}
// Stream
// Stateless intermediate operations from Stream
@Override
public Stream<P_OUT> unordered() {
if (!isOrdered())
return this;
return new StatelessOp<P_OUT, P_OUT>(this, StreamShape.REFERENCE, StreamOpFlag.NOT_ORDERED) {
@Override
Sink<P_OUT> opWrapSink(int flags, Sink<P_OUT> sink) {
return sink;
}
};
}
@Override
public final Stream<P_OUT> filter(Predicate<? super P_OUT> predicate) {
Objects.requireNonNull(predicate);
return new StatelessOp<P_OUT, P_OUT>(this, StreamShape.REFERENCE,
StreamOpFlag.NOT_SIZED) {
@Override
Sink<P_OUT> opWrapSink(int flags, Sink<P_OUT> sink) {
return new Sink.ChainedReference<P_OUT, P_OUT>(sink) {
@Override
public void begin(long size) {
downstream.begin(-1);
}
@Override
public void accept(P_OUT u) {
if (predicate.test(u))
downstream.accept(u);
}
};
}
};
}
@Override
@SuppressWarnings("unchecked")
public final <R> Stream<R> map(Function<? super P_OUT, ? extends R> mapper) {
Objects.requireNonNull(mapper);
return new StatelessOp<P_OUT, R>(this, StreamShape.REFERENCE,
StreamOpFlag.NOT_SORTED | StreamOpFlag.NOT_DISTINCT) {
@Override
Sink<P_OUT> opWrapSink(int flags, Sink<R> sink) {
return new Sink.ChainedReference<P_OUT, R>(sink) {
@Override
public void accept(P_OUT u) {
downstream.accept(mapper.apply(u));
}
};
}
};
}
@Override
public final IntStream mapToInt(ToIntFunction<? super P_OUT> mapper) {
Objects.requireNonNull(mapper);
return new IntPipeline.StatelessOp<P_OUT>(this, StreamShape.REFERENCE,
StreamOpFlag.NOT_SORTED | StreamOpFlag.NOT_DISTINCT) {
@Override
Sink<P_OUT> opWrapSink(int flags, Sink<Integer> sink) {
return new Sink.ChainedReference<P_OUT, Integer>(sink) {
@Override
public void accept(P_OUT u) {
downstream.accept(mapper.applyAsInt(u));
}
};
}
};
}
@Override
public final LongStream mapToLong(ToLongFunction<? super P_OUT> mapper) {
Objects.requireNonNull(mapper);
return new LongPipeline.StatelessOp<P_OUT>(this, StreamShape.REFERENCE,
StreamOpFlag.NOT_SORTED | StreamOpFlag.NOT_DISTINCT) {
@Override
Sink<P_OUT> opWrapSink(int flags, Sink<Long> sink) {
return new Sink.ChainedReference<P_OUT, Long>(sink) {
@Override
public void accept(P_OUT u) {
downstream.accept(mapper.applyAsLong(u));
}
};
}
};
}
@Override
public final DoubleStream mapToDouble(ToDoubleFunction<? super P_OUT> mapper) {
Objects.requireNonNull(mapper);
return new DoublePipeline.StatelessOp<P_OUT>(this, StreamShape.REFERENCE,
StreamOpFlag.NOT_SORTED | StreamOpFlag.NOT_DISTINCT) {
@Override
Sink<P_OUT> opWrapSink(int flags, Sink<Double> sink) {
return new Sink.ChainedReference<P_OUT, Double>(sink) {
@Override
public void accept(P_OUT u) {
downstream.accept(mapper.applyAsDouble(u));
}
};
}
};
}
@Override
public final <R> Stream<R> flatMap(Function<? super P_OUT, ? extends Stream<? extends R>> mapper) {
Objects.requireNonNull(mapper);
// We can do better than this, by polling cancellationRequested when stream is infinite
return new StatelessOp<P_OUT, R>(this, StreamShape.REFERENCE,
StreamOpFlag.NOT_SORTED | StreamOpFlag.NOT_DISTINCT | StreamOpFlag.NOT_SIZED) {
@Override
Sink<P_OUT> opWrapSink(int flags, Sink<R> sink) {
return new Sink.ChainedReference<P_OUT, R>(sink) {
@Override
public void begin(long size) {
downstream.begin(-1);
}
@Override
public void accept(P_OUT u) {
try (Stream<? extends R> result = mapper.apply(u)) {
// We can do better that this too; optimize for depth=0 case and just grab spliterator and forEach it
if (result != null)
result.sequential().forEach(downstream);
}
}
};
}
};
}
@Override
public final IntStream flatMapToInt(Function<? super P_OUT, ? extends IntStream> mapper) {
Objects.requireNonNull(mapper);
// We can do better than this, by polling cancellationRequested when stream is infinite
return new IntPipeline.StatelessOp<P_OUT>(this, StreamShape.REFERENCE,
StreamOpFlag.NOT_SORTED | StreamOpFlag.NOT_DISTINCT | StreamOpFlag.NOT_SIZED) {
@Override
Sink<P_OUT> opWrapSink(int flags, Sink<Integer> sink) {
return new Sink.ChainedReference<P_OUT, Integer>(sink) {
IntConsumer downstreamAsInt = downstream::accept;
@Override
public void begin(long size) {
downstream.begin(-1);
}
@Override
public void accept(P_OUT u) {
try (IntStream result = mapper.apply(u)) {
// We can do better that this too; optimize for depth=0 case and just grab spliterator and forEach it
if (result != null)
result.sequential().forEach(downstreamAsInt);
}
}
};
}
};
}
@Override
public final DoubleStream flatMapToDouble(Function<? super P_OUT, ? extends DoubleStream> mapper) {
Objects.requireNonNull(mapper);
// We can do better than this, by polling cancellationRequested when stream is infinite
return new DoublePipeline.StatelessOp<P_OUT>(this, StreamShape.REFERENCE,
StreamOpFlag.NOT_SORTED | StreamOpFlag.NOT_DISTINCT | StreamOpFlag.NOT_SIZED) {
@Override
Sink<P_OUT> opWrapSink(int flags, Sink<Double> sink) {
return new Sink.ChainedReference<P_OUT, Double>(sink) {
DoubleConsumer downstreamAsDouble = downstream::accept;
@Override
public void begin(long size) {
downstream.begin(-1);
}
@Override
public void accept(P_OUT u) {
try (DoubleStream result = mapper.apply(u)) {
// We can do better that this too; optimize for depth=0 case and just grab spliterator and forEach it
if (result != null)
result.sequential().forEach(downstreamAsDouble);
}
}
};
}
};
}
@Override
public final LongStream flatMapToLong(Function<? super P_OUT, ? extends LongStream> mapper) {
Objects.requireNonNull(mapper);
// We can do better than this, by polling cancellationRequested when stream is infinite
return new LongPipeline.StatelessOp<P_OUT>(this, StreamShape.REFERENCE,
StreamOpFlag.NOT_SORTED | StreamOpFlag.NOT_DISTINCT | StreamOpFlag.NOT_SIZED) {
@Override
Sink<P_OUT> opWrapSink(int flags, Sink<Long> sink) {
return new Sink.ChainedReference<P_OUT, Long>(sink) {
LongConsumer downstreamAsLong = downstream::accept;
@Override
public void begin(long size) {
downstream.begin(-1);
}
@Override
public void accept(P_OUT u) {
try (LongStream result = mapper.apply(u)) {
// We can do better that this too; optimize for depth=0 case and just grab spliterator and forEach it
if (result != null)
result.sequential().forEach(downstreamAsLong);
}
}
};
}
};
}
@Override
public final Stream<P_OUT> peek(Consumer<? super P_OUT> action) {
Objects.requireNonNull(action);
return new StatelessOp<P_OUT, P_OUT>(this, StreamShape.REFERENCE,
0) {
@Override
Sink<P_OUT> opWrapSink(int flags, Sink<P_OUT> sink) {
return new Sink.ChainedReference<P_OUT, P_OUT>(sink) {
@Override
public void accept(P_OUT u) {
action.accept(u);
downstream.accept(u);
}
};
}
};
}
// Stateful intermediate operations from Stream
@Override
public final Stream<P_OUT> distinct() {
return DistinctOps.makeRef(this);
}
@Override
public final Stream<P_OUT> sorted() {
return SortedOps.makeRef(this);
}
@Override
public final Stream<P_OUT> sorted(Comparator<? super P_OUT> comparator) {
return SortedOps.makeRef(this, comparator);
}
private Stream<P_OUT> slice(long skip, long limit) {
return SliceOps.makeRef(this, skip, limit);
}
@Override
public final Stream<P_OUT> limit(long maxSize) {
if (maxSize < 0)
throw new IllegalArgumentException(Long.toString(maxSize));
return slice(0, maxSize);
}
@Override
public final Stream<P_OUT> substream(long startingOffset) {
if (startingOffset < 0)
throw new IllegalArgumentException(Long.toString(startingOffset));
if (startingOffset == 0)
return this;
else
return slice(startingOffset, -1);
}
@Override
public final Stream<P_OUT> substream(long startingOffset, long endingOffset) {
if (startingOffset < 0 || endingOffset < startingOffset)
throw new IllegalArgumentException(String.format("substream(%d, %d)", startingOffset, endingOffset));
return slice(startingOffset, endingOffset - startingOffset);
}
// Terminal operations from Stream
@Override
public void forEach(Consumer<? super P_OUT> action) {
evaluate(ForEachOps.makeRef(action, false));
}
@Override
public void forEachOrdered(Consumer<? super P_OUT> action) {
evaluate(ForEachOps.makeRef(action, true));
}
@Override
@SuppressWarnings("unchecked")
public final <A> A[] toArray(IntFunction<A[]> generator) {
// Since A has no relation to U (not possible to declare that A is an upper bound of U)
// there will be no static type checking.
// Therefore use a raw type and assume A == U rather than propagating the separation of A and U
// throughout the code-base.
// The runtime type of U is never checked for equality with the component type of the runtime type of A[].
// Runtime checking will be performed when an element is stored in A[], thus if A is not a
// super type of U an ArrayStoreException will be thrown.
@SuppressWarnings("rawtypes")
IntFunction rawGenerator = (IntFunction) generator;
return (A[]) Nodes.flatten(evaluateToArrayNode(rawGenerator), rawGenerator)
.asArray(rawGenerator);
}
@Override
public final Object[] toArray() {
return toArray(Object[]::new);
}
@Override
public final boolean anyMatch(Predicate<? super P_OUT> predicate) {
return evaluate(MatchOps.makeRef(predicate, MatchOps.MatchKind.ANY));
}
@Override
public final boolean allMatch(Predicate<? super P_OUT> predicate) {
return evaluate(MatchOps.makeRef(predicate, MatchOps.MatchKind.ALL));
}
@Override
public final boolean noneMatch(Predicate<? super P_OUT> predicate) {
return evaluate(MatchOps.makeRef(predicate, MatchOps.MatchKind.NONE));
}
@Override
public final Optional<P_OUT> findFirst() {
return evaluate(FindOps.makeRef(true));
}
@Override
public final Optional<P_OUT> findAny() {
return evaluate(FindOps.makeRef(false));
}
@Override
public final P_OUT reduce(final P_OUT identity, final BinaryOperator<P_OUT> accumulator) {
return evaluate(ReduceOps.makeRef(identity, accumulator, accumulator));
}
@Override
public final Optional<P_OUT> reduce(BinaryOperator<P_OUT> accumulator) {
return evaluate(ReduceOps.makeRef(accumulator));
}
@Override
public final <R> R reduce(R identity, BiFunction<R, ? super P_OUT, R> accumulator, BinaryOperator<R> combiner) {
return evaluate(ReduceOps.makeRef(identity, accumulator, combiner));
}
@Override
@SuppressWarnings("unchecked")
public final <R, A> R collect(Collector<? super P_OUT, A, R> collector) {
A container;
if (isParallel()
&& (collector.characteristics().contains(Collector.Characteristics.CONCURRENT))
&& (!isOrdered() || collector.characteristics().contains(Collector.Characteristics.UNORDERED))) {
container = collector.supplier().get();
BiConsumer<A, ? super P_OUT> accumulator = collector.accumulator();
forEach(u -> accumulator.accept(container, u));
}
else {
container = evaluate(ReduceOps.makeRef(collector));
}
return collector.characteristics().contains(Collector.Characteristics.IDENTITY_FINISH)
? (R) container
: collector.finisher().apply(container);
}
@Override
public final <R> R collect(Supplier<R> supplier,
BiConsumer<R, ? super P_OUT> accumulator,
BiConsumer<R, R> combiner) {
return evaluate(ReduceOps.makeRef(supplier, accumulator, combiner));
}
@Override
public final Optional<P_OUT> max(Comparator<? super P_OUT> comparator) {
return reduce(BinaryOperator.maxBy(comparator));
}
@Override
public final Optional<P_OUT> min(Comparator<? super P_OUT> comparator) {
return reduce(BinaryOperator.minBy(comparator));
}
@Override
public final long count() {
return mapToLong(e -> 1L).sum();
}
//
/**
* Source stage of a ReferencePipeline.
*
* @param <E_IN> type of elements in the upstream source
* @param <E_OUT> type of elements in produced by this stage
* @since 1.8
*/
static class Head<E_IN, E_OUT> extends ReferencePipeline<E_IN, E_OUT> {
/**
* Constructor for the source stage of a Stream.
*
* @param source {@code Supplier<Spliterator>} describing the stream
* source
* @param sourceFlags the source flags for the stream source, described
* in {@link StreamOpFlag}
*/
Head(Supplier<? extends Spliterator<?>> source,
int sourceFlags, boolean parallel) {
super(source, sourceFlags, parallel);
}
/**
* Constructor for the source stage of a Stream.
*
* @param source {@code Spliterator} describing the stream source
* @param sourceFlags the source flags for the stream source, described
* in {@link StreamOpFlag}
*/
Head(Spliterator<?> source,
int sourceFlags, boolean parallel) {
super(source, sourceFlags, parallel);
}
@Override
final boolean opIsStateful() {
throw new UnsupportedOperationException();
}
@Override
final Sink<E_IN> opWrapSink(int flags, Sink<E_OUT> sink) {
throw new UnsupportedOperationException();
}
// Optimized sequential terminal operations for the head of the pipeline
@Override
public void forEach(Consumer<? super E_OUT> action) {
if (!isParallel()) {
sourceStageSpliterator().forEachRemaining(action);
}
else {
super.forEach(action);
}
}
@Override
public void forEachOrdered(Consumer<? super E_OUT> action) {
if (!isParallel()) {
sourceStageSpliterator().forEachRemaining(action);
}
else {
super.forEachOrdered(action);
}
}
}
/**
* Base class for a stateless intermediate stage of a Stream.
*
* @param <E_IN> type of elements in the upstream source
* @param <E_OUT> type of elements in produced by this stage
* @since 1.8
*/
abstract static class StatelessOp<E_IN, E_OUT>
extends ReferencePipeline<E_IN, E_OUT> {
/**
* Construct a new Stream by appending a stateless intermediate
* operation to an existing stream.
*
* @param upstream The upstream pipeline stage
* @param inputShape The stream shape for the upstream pipeline stage
* @param opFlags Operation flags for the new stage
*/
StatelessOp(AbstractPipeline<?, E_IN, ?> upstream,
StreamShape inputShape,
int opFlags) {
super(upstream, opFlags);
assert upstream.getOutputShape() == inputShape;
}
@Override
final boolean opIsStateful() {
return false;
}
}
/**
* Base class for a stateful intermediate stage of a Stream.
*
* @param <E_IN> type of elements in the upstream source
* @param <E_OUT> type of elements in produced by this stage
* @since 1.8
*/
abstract static class StatefulOp<E_IN, E_OUT>
extends ReferencePipeline<E_IN, E_OUT> {
/**
* Construct a new Stream by appending a stateful intermediate operation
* to an existing stream.
* @param upstream The upstream pipeline stage
* @param inputShape The stream shape for the upstream pipeline stage
* @param opFlags Operation flags for the new stage
*/
StatefulOp(AbstractPipeline<?, E_IN, ?> upstream,
StreamShape inputShape,
int opFlags) {
super(upstream, opFlags);
assert upstream.getOutputShape() == inputShape;
}
@Override
final boolean opIsStateful() {
return true;
}
@Override
abstract <P_IN> Node<E_OUT> opEvaluateParallel(PipelineHelper<E_OUT> helper,
Spliterator<P_IN> spliterator,
IntFunction<E_OUT[]> generator);
}
}