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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
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*
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* accompanied this code).
*
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package java8.util.stream;
import java8.util.DoubleSummaryStatistics;
import java8.util.Objects;
import java8.util.PrimitiveIterator;
import java8.util.function.BiConsumer;
import java8.util.function.BinaryOperator;
import java8.util.function.DoubleBinaryOperator;
import java8.util.function.DoubleConsumer;
import java8.util.function.DoubleFunction;
import java8.util.function.DoublePredicate;
import java8.util.function.DoubleToIntFunction;
import java8.util.function.DoubleToLongFunction;
import java8.util.function.DoubleUnaryOperator;
import java8.util.function.IntFunction;
import java8.util.function.ObjDoubleConsumer;
import java8.util.function.Supplier;
import java8.util.OptionalDouble;
import java8.util.Spliterator;
import java8.util.Spliterators;
/**
* Abstract base class for an intermediate pipeline stage or pipeline source
* stage implementing whose elements are of type {@code double}.
*
* @param type of elements in the upstream source
*
* @since 1.8
*/
abstract class DoublePipeline
extends AbstractPipeline
implements DoubleStream {
/**
* Constructor for the head of a stream pipeline.
*
* @param source {@code Supplier} describing the stream source
* @param sourceFlags the source flags for the stream source, described in
* {@link StreamOpFlag}
*/
DoublePipeline(Supplier> 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}
*/
DoublePipeline(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.
* @param opFlags the operation flags
*/
DoublePipeline(AbstractPipeline upstream, int opFlags) {
super(upstream, opFlags);
}
/**
* Adapt a {@code Sink to a {@code DoubleConsumer}, ideally simply
* by casting.
*/
private static DoubleConsumer adapt(Sink sink) {
if (sink instanceof DoubleConsumer) {
return (DoubleConsumer) sink;
} else {
return sink::accept;
}
}
/**
* Adapt a {@code Spliterator} to a {@code Spliterator.OfDouble}.
*
* Implementation Note:
* The implementation attempts to cast to a Spliterator.OfDouble, and throws
* an exception if this cast is not possible.
*/
private static Spliterator.OfDouble adapt(Spliterator s) {
if (s instanceof Spliterator.OfDouble) {
return (Spliterator.OfDouble) s;
} else {
throw new UnsupportedOperationException("DoubleStream.adapt(Spliterator s)");
}
}
// Shape-specific methods
@Override
final StreamShape getOutputShape() {
return StreamShape.DOUBLE_VALUE;
}
@Override
final Node evaluateToNode(PipelineHelper helper,
Spliterator spliterator,
boolean flattenTree,
IntFunction generator) {
return Nodes.collectDouble(helper, spliterator, flattenTree);
}
@Override
final Spliterator wrap(PipelineHelper ph,
Supplier> supplier,
boolean isParallel) {
return new StreamSpliterators.DoubleWrappingSpliterator<>(ph, supplier, isParallel);
}
@Override
@SuppressWarnings("unchecked")
final Spliterator.OfDouble lazySpliterator(Supplier> supplier) {
return new StreamSpliterators.DelegatingSpliterator.OfDouble((Supplier) supplier);
}
@Override
final boolean forEachWithCancel(Spliterator spliterator, Sink sink) {
Spliterator.OfDouble spl = adapt(spliterator);
DoubleConsumer adaptedSink = adapt(sink);
boolean cancelled;
do { } while (!(cancelled = sink.cancellationRequested()) && spl.tryAdvance(adaptedSink));
return cancelled;
}
@Override
final Node.Builder makeNodeBuilder(long exactSizeIfKnown, IntFunction generator) {
return Nodes.doubleBuilder(exactSizeIfKnown);
}
private Stream mapToObj(DoubleFunction mapper, int opFlags) {
return new ReferencePipeline.StatelessOp(this, StreamShape.DOUBLE_VALUE, opFlags) {
@Override
Sink opWrapSink(int flags, Sink sink) {
return new Sink.ChainedDouble(sink) {
@Override
public void accept(double t) {
downstream.accept(mapper.apply(t));
}
};
}
};
}
// DoubleStream
@Override
public final PrimitiveIterator.OfDouble iterator() {
return Spliterators.iterator(spliterator());
}
@Override
public final Spliterator.OfDouble spliterator() {
return adapt(super.spliterator());
}
// Stateless intermediate ops from DoubleStream
@Override
public final Stream boxed() {
return mapToObj(Double::valueOf, 0);
}
@Override
public final DoubleStream map(DoubleUnaryOperator mapper) {
Objects.requireNonNull(mapper);
return new StatelessOp(this, StreamShape.DOUBLE_VALUE,
StreamOpFlag.NOT_SORTED | StreamOpFlag.NOT_DISTINCT) {
@Override
Sink opWrapSink(int flags, Sink sink) {
return new Sink.ChainedDouble(sink) {
@Override
public void accept(double t) {
downstream.accept(mapper.applyAsDouble(t));
}
};
}
};
}
@Override
public final Stream mapToObj(DoubleFunction mapper) {
Objects.requireNonNull(mapper);
return mapToObj(mapper, StreamOpFlag.NOT_SORTED | StreamOpFlag.NOT_DISTINCT);
}
@Override
public final IntStream mapToInt(DoubleToIntFunction mapper) {
Objects.requireNonNull(mapper);
return new IntPipeline.StatelessOp(this, StreamShape.DOUBLE_VALUE,
StreamOpFlag.NOT_SORTED | StreamOpFlag.NOT_DISTINCT) {
@Override
Sink opWrapSink(int flags, Sink sink) {
return new Sink.ChainedDouble(sink) {
@Override
public void accept(double t) {
downstream.accept(mapper.applyAsInt(t));
}
};
}
};
}
@Override
public final LongStream mapToLong(DoubleToLongFunction mapper) {
Objects.requireNonNull(mapper);
return new LongPipeline.StatelessOp(this, StreamShape.DOUBLE_VALUE,
StreamOpFlag.NOT_SORTED | StreamOpFlag.NOT_DISTINCT) {
@Override
Sink opWrapSink(int flags, Sink sink) {
return new Sink.ChainedDouble(sink) {
@Override
public void accept(double t) {
downstream.accept(mapper.applyAsLong(t));
}
};
}
};
}
@Override
public final DoubleStream flatMap(DoubleFunction mapper) {
Objects.requireNonNull(mapper);
return new StatelessOp(this, StreamShape.DOUBLE_VALUE,
StreamOpFlag.NOT_SORTED | StreamOpFlag.NOT_DISTINCT | StreamOpFlag.NOT_SIZED) {
@Override
Sink opWrapSink(int flags, Sink sink) {
return new Sink.ChainedDouble(sink) {
// true if cancellationRequested() has been called
boolean cancellationRequested;
// cache the consumer to avoid creation on every accepted element
DoubleConsumer downstreamAsDouble = downstream::accept;
@Override
public void begin(long size) {
downstream.begin(-1);
}
@Override
public void accept(double t) {
DoubleStream result = null;
try {
result = mapper.apply(t);
if (result != null) {
if (!cancellationRequested) {
result.sequential().forEach(downstreamAsDouble);
}
else {
Spliterator.OfDouble s = result.sequential().spliterator();
do { } while (!downstream.cancellationRequested() && s.tryAdvance(downstreamAsDouble));
}
}
} finally {
if (result != null) {
result.close();
}
}
}
@Override
public boolean cancellationRequested() {
// If this method is called then an operation within the stream
// pipeline is short-circuiting (see AbstractPipeline.copyInto).
// Note that we cannot differentiate between an upstream or
// downstream operation
cancellationRequested = true;
return downstream.cancellationRequested();
}
};
}
};
}
@Override
public DoubleStream unordered() {
if (!isOrdered())
return this;
return new StatelessOp(this, StreamShape.DOUBLE_VALUE, StreamOpFlag.NOT_ORDERED) {
@Override
Sink opWrapSink(int flags, Sink sink) {
return sink;
}
};
}
@Override
public final DoubleStream filter(DoublePredicate predicate) {
Objects.requireNonNull(predicate);
return new StatelessOp(this, StreamShape.DOUBLE_VALUE,
StreamOpFlag.NOT_SIZED) {
@Override
Sink opWrapSink(int flags, Sink sink) {
return new Sink.ChainedDouble(sink) {
@Override
public void begin(long size) {
downstream.begin(-1);
}
@Override
public void accept(double t) {
if (predicate.test(t))
downstream.accept(t);
}
};
}
};
}
@Override
public final DoubleStream peek(DoubleConsumer action) {
Objects.requireNonNull(action);
return new StatelessOp(this, StreamShape.DOUBLE_VALUE,
0) {
@Override
Sink opWrapSink(int flags, Sink sink) {
return new Sink.ChainedDouble(sink) {
@Override
public void accept(double t) {
action.accept(t);
downstream.accept(t);
}
};
}
};
}
// Stateful intermediate ops from DoubleStream
@Override
public final DoubleStream limit(long maxSize) {
if (maxSize < 0)
throw new IllegalArgumentException(Long.toString(maxSize));
return SliceOps.makeDouble(this, (long) 0, maxSize);
}
@Override
public final DoubleStream skip(long n) {
if (n < 0)
throw new IllegalArgumentException(Long.toString(n));
if (n == 0)
return this;
else {
long limit = -1;
return SliceOps.makeDouble(this, n, limit);
}
}
@Override
public final DoubleStream takeWhile(DoublePredicate predicate) {
return WhileOps.makeTakeWhileDouble(this, predicate);
}
@Override
public final DoubleStream dropWhile(DoublePredicate predicate) {
return WhileOps.makeDropWhileDouble(this, predicate);
}
@Override
public final DoubleStream sorted() {
return SortedOps.makeDouble(this);
}
@Override
public final DoubleStream distinct() {
// While functional and quick to implement, this approach is not very efficient.
// An efficient version requires a double-specific map/set implementation.
return boxed().distinct().mapToDouble(i -> (double) i);
}
// Terminal ops from DoubleStream
@Override
public void forEach(DoubleConsumer consumer) {
evaluate(ForEachOps.makeDouble(consumer, false));
}
@Override
public void forEachOrdered(DoubleConsumer consumer) {
evaluate(ForEachOps.makeDouble(consumer, true));
}
@Override
public final double sum() {
/*
* In the arrays allocated for the collect operation, index 0
* holds the high-order bits of the running sum, index 1 holds
* the low-order bits of the sum computed via compensated
* summation, and index 2 holds the simple sum used to compute
* the proper result if the stream contains infinite values of
* the same sign.
*/
double[] summation = collect(() -> new double[3],
(ll, d) -> {
Collectors.sumWithCompensation(ll, d);
ll[2] += d;
},
(ll, rr) -> {
Collectors.sumWithCompensation(ll, rr[0]);
Collectors.sumWithCompensation(ll, rr[1]);
ll[2] += rr[2];
});
return Collectors.computeFinalSum(summation);
}
@Override
public final OptionalDouble min() {
return reduce(Math::min);
}
@Override
public final OptionalDouble max() {
return reduce(Math::max);
}
/**
* {@inheritDoc}
*
* Implementation Note:
The {@code double} format can represent all
* consecutive integers in the range -253 to
* 253. If the pipeline has more than 253
* values, the divisor in the average computation will saturate at
* 253, leading to additional numerical errors.
*/
@Override
public final OptionalDouble average() {
/*
* In the arrays allocated for the collect operation, index 0
* holds the high-order bits of the running sum, index 1 holds
* the low-order bits of the sum computed via compensated
* summation, index 2 holds the number of values seen, index 3
* holds the simple sum.
*/
double[] avg = collect(() -> new double[4],
(ll, d) -> {
ll[2]++;
Collectors.sumWithCompensation(ll, d);
ll[3] += d;
},
(ll, rr) -> {
Collectors.sumWithCompensation(ll, rr[0]);
Collectors.sumWithCompensation(ll, rr[1]);
ll[2] += rr[2];
ll[3] += rr[3];
});
return avg[2] > 0
? OptionalDouble.of(Collectors.computeFinalSum(avg) / avg[2])
: OptionalDouble.empty();
}
@Override
public final long count() {
return evaluate(ReduceOps.makeDoubleCounting());
}
@Override
public final DoubleSummaryStatistics summaryStatistics() {
return collect(Collectors.DBL_SUM_STATS, DoubleSummaryStatistics::accept,
DoubleSummaryStatistics::combine);
}
@Override
public final double reduce(double identity, DoubleBinaryOperator op) {
return evaluate(ReduceOps.makeDouble(identity, op));
}
@Override
public final OptionalDouble reduce(DoubleBinaryOperator op) {
return evaluate(ReduceOps.makeDouble(op));
}
@Override
public final R collect(Supplier supplier,
ObjDoubleConsumer accumulator,
BiConsumer combiner) {
Objects.requireNonNull(combiner);
BinaryOperator operator = (left, right) -> {
combiner.accept(left, right);
return left;
};
return evaluate(ReduceOps.makeDouble(supplier, accumulator, operator));
}
@Override
public final boolean anyMatch(DoublePredicate predicate) {
return evaluate(MatchOps.makeDouble(predicate, MatchOps.MatchKind.ANY));
}
@Override
public final boolean allMatch(DoublePredicate predicate) {
return evaluate(MatchOps.makeDouble(predicate, MatchOps.MatchKind.ALL));
}
@Override
public final boolean noneMatch(DoublePredicate predicate) {
return evaluate(MatchOps.makeDouble(predicate, MatchOps.MatchKind.NONE));
}
@Override
public final OptionalDouble findFirst() {
return evaluate(FindOps.makeDouble(true));
}
@Override
public final OptionalDouble findAny() {
return evaluate(FindOps.makeDouble(false));
}
@Override
public final double[] toArray() {
return Nodes.flattenDouble((Node.OfDouble) evaluateToArrayNode(WhileOps.DOUBLE_ARR_GEN))
.asPrimitiveArray();
}
//
/**
* Source stage of a DoubleStream
*
* @param type of elements in the upstream source
*/
static class Head extends DoublePipeline {
/**
* Constructor for the source stage of a DoubleStream.
*
* @param source {@code Supplier} 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
*/
Head(Supplier> source,
int sourceFlags, boolean parallel) {
super(source, sourceFlags, parallel);
}
/**
* Constructor for the source stage of a DoubleStream.
*
* @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
*/
Head(Spliterator source,
int sourceFlags, boolean parallel) {
super(source, sourceFlags, parallel);
}
@Override
final boolean opIsStateful() {
throw new UnsupportedOperationException();
}
@Override
final Sink opWrapSink(int flags, Sink sink) {
throw new UnsupportedOperationException();
}
// Optimized sequential terminal operations for the head of the pipeline
@Override
public void forEach(DoubleConsumer consumer) {
if (!isParallel()) {
adapt(sourceStageSpliterator()).forEachRemaining(consumer);
}
else {
super.forEach(consumer);
}
}
@Override
public void forEachOrdered(DoubleConsumer consumer) {
if (!isParallel()) {
adapt(sourceStageSpliterator()).forEachRemaining(consumer);
}
else {
super.forEachOrdered(consumer);
}
}
}
/**
* Base class for a stateless intermediate stage of a DoubleStream.
*
* @param type of elements in the upstream source
* @since 1.8
*/
abstract static class StatelessOp extends DoublePipeline {
/**
* Construct a new DoubleStream 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 upstream,
StreamShape inputShape,
int opFlags) {
super(upstream, opFlags);
}
@Override
final boolean opIsStateful() {
return false;
}
}
/**
* Base class for a stateful intermediate stage of a DoubleStream.
*
* @param type of elements in the upstream source
* @since 1.8
*/
abstract static class StatefulOp extends DoublePipeline {
/**
* Construct a new DoubleStream 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 upstream,
StreamShape inputShape,
int opFlags) {
super(upstream, opFlags);
}
@Override
final boolean opIsStateful() {
return true;
}
@Override
abstract Node opEvaluateParallel(PipelineHelper helper,
Spliterator spliterator,
IntFunction generator);
}
}