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1 /*
2  * Copyright (c) 2012, 2013, Oracle and/or its affiliates. All rights reserved.
3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4  *
5  * This code is free software; you can redistribute it and/or modify it
6  * under the terms of the GNU General Public License version 2 only, as
7  * published by the Free Software Foundation.  Oracle designates this
8  * particular file as subject to the "Classpath" exception as provided
9  * by Oracle in the LICENSE file that accompanied this code.
10  *
11  * This code is distributed in the hope that it will be useful, but WITHOUT
12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14  * version 2 for more details (a copy is included in the LICENSE file that
15  * accompanied this code).
16  *
17  * You should have received a copy of the GNU General Public License version
18  * 2 along with this work; if not, write to the Free Software Foundation,
19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20  *
21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22  * or visit www.oracle.com if you need additional information or have any
23  * questions.
24  */
25 package java.util.stream;
26 
27 import java.util.Comparator;
28 import java.util.Iterator;
29 import java.util.Objects;
30 import java.util.Optional;
31 import java.util.Spliterator;
32 import java.util.Spliterators;
33 import java.util.function.BiConsumer;
34 import java.util.function.BiFunction;
35 import java.util.function.BinaryOperator;
36 import java.util.function.Consumer;
37 import java.util.function.DoubleConsumer;
38 import java.util.function.Function;
39 import java.util.function.IntConsumer;
40 import java.util.function.IntFunction;
41 import java.util.function.LongConsumer;
42 import java.util.function.Predicate;
43 import java.util.function.Supplier;
44 import java.util.function.ToDoubleFunction;
45 import java.util.function.ToIntFunction;
46 import java.util.function.ToLongFunction;
47 
48 /**
49  * Abstract base class for an intermediate pipeline stage or pipeline source
50  * stage implementing whose elements are of type {@code U}.
51  *
52  * @param <P_IN> type of elements in the upstream source
53  * @param <P_OUT> type of elements in produced by this stage
54  *
55  * @since 1.8
56  * @hide Visible for CTS testing only (OpenJDK8 tests).
57  */
58 // Android-changed: Made public for CTS tests only.
59 public abstract class ReferencePipeline<P_IN, P_OUT>
60         extends AbstractPipeline<P_IN, P_OUT, Stream<P_OUT>>
61         implements Stream<P_OUT>  {
62 
63     /**
64      * Constructor for the head of a stream pipeline.
65      *
66      * @param source {@code Supplier<Spliterator>} describing the stream source
67      * @param sourceFlags the source flags for the stream source, described in
68      *        {@link StreamOpFlag}
69      * @param parallel {@code true} if the pipeline is parallel
70      */
ReferencePipeline(Supplier<? extends Spliterator<?>> source, int sourceFlags, boolean parallel)71     ReferencePipeline(Supplier<? extends Spliterator<?>> source,
72                       int sourceFlags, boolean parallel) {
73         super(source, sourceFlags, parallel);
74     }
75 
76     /**
77      * Constructor for the head of a stream pipeline.
78      *
79      * @param source {@code Spliterator} describing the stream source
80      * @param sourceFlags The source flags for the stream source, described in
81      *        {@link StreamOpFlag}
82      * @param parallel {@code true} if the pipeline is parallel
83      */
ReferencePipeline(Spliterator<?> source, int sourceFlags, boolean parallel)84     ReferencePipeline(Spliterator<?> source,
85                       int sourceFlags, boolean parallel) {
86         super(source, sourceFlags, parallel);
87     }
88 
89     /**
90      * Constructor for appending an intermediate operation onto an existing
91      * pipeline.
92      *
93      * @param upstream the upstream element source.
94      */
ReferencePipeline(AbstractPipeline<?, P_IN, ?> upstream, int opFlags)95     ReferencePipeline(AbstractPipeline<?, P_IN, ?> upstream, int opFlags) {
96         super(upstream, opFlags);
97     }
98 
99     // Shape-specific methods
100 
101     @Override
102     // Android-changed: Make public, to match the method it's overriding.
getOutputShape()103     public final StreamShape getOutputShape() {
104         return StreamShape.REFERENCE;
105     }
106 
107     @Override
108     // Android-changed: Make public, to match the method it's overriding.
evaluateToNode(PipelineHelper<P_OUT> helper, Spliterator<P_IN> spliterator, boolean flattenTree, IntFunction<P_OUT[]> generator)109     public final <P_IN> Node<P_OUT> evaluateToNode(PipelineHelper<P_OUT> helper,
110                                         Spliterator<P_IN> spliterator,
111                                         boolean flattenTree,
112                                         IntFunction<P_OUT[]> generator) {
113         return Nodes.collect(helper, spliterator, flattenTree, generator);
114     }
115 
116     @Override
117     // Android-changed: Make public, to match the method it's overriding.
wrap(PipelineHelper<P_OUT> ph, Supplier<Spliterator<P_IN>> supplier, boolean isParallel)118     public final <P_IN> Spliterator<P_OUT> wrap(PipelineHelper<P_OUT> ph,
119                                      Supplier<Spliterator<P_IN>> supplier,
120                                      boolean isParallel) {
121         return new StreamSpliterators.WrappingSpliterator<>(ph, supplier, isParallel);
122     }
123 
124     @Override
125     // Android-changed: Make public, to match the method it's overriding.
lazySpliterator(Supplier<? extends Spliterator<P_OUT>> supplier)126     public final Spliterator<P_OUT> lazySpliterator(Supplier<? extends Spliterator<P_OUT>> supplier) {
127         return new StreamSpliterators.DelegatingSpliterator<>(supplier);
128     }
129 
130     @Override
131     // Android-changed: Make public, to match the method it's overriding.
forEachWithCancel(Spliterator<P_OUT> spliterator, Sink<P_OUT> sink)132     public final void forEachWithCancel(Spliterator<P_OUT> spliterator, Sink<P_OUT> sink) {
133         do { } while (!sink.cancellationRequested() && spliterator.tryAdvance(sink));
134     }
135 
136     @Override
137     // Android-changed: Make public, to match the method it's overriding.
makeNodeBuilder(long exactSizeIfKnown, IntFunction<P_OUT[]> generator)138     public final Node.Builder<P_OUT> makeNodeBuilder(long exactSizeIfKnown, IntFunction<P_OUT[]> generator) {
139         return Nodes.builder(exactSizeIfKnown, generator);
140     }
141 
142 
143     // BaseStream
144 
145     @Override
iterator()146     public final Iterator<P_OUT> iterator() {
147         return Spliterators.iterator(spliterator());
148     }
149 
150 
151     // Stream
152 
153     // Stateless intermediate operations from Stream
154 
155     @Override
unordered()156     public Stream<P_OUT> unordered() {
157         if (!isOrdered())
158             return this;
159         return new StatelessOp<P_OUT, P_OUT>(this, StreamShape.REFERENCE, StreamOpFlag.NOT_ORDERED) {
160             @Override
161             // Android-changed: Make public, to match the method it's overriding.
162             public Sink<P_OUT> opWrapSink(int flags, Sink<P_OUT> sink) {
163                 return sink;
164             }
165         };
166     }
167 
168     @Override
169     public final Stream<P_OUT> filter(Predicate<? super P_OUT> predicate) {
170         Objects.requireNonNull(predicate);
171         return new StatelessOp<P_OUT, P_OUT>(this, StreamShape.REFERENCE,
172                                      StreamOpFlag.NOT_SIZED) {
173             @Override
174             // Android-changed: Make public, to match the method it's overriding.
175             public Sink<P_OUT> opWrapSink(int flags, Sink<P_OUT> sink) {
176                 return new Sink.ChainedReference<P_OUT, P_OUT>(sink) {
177                     @Override
178                     public void begin(long size) {
179                         downstream.begin(-1);
180                     }
181 
182                     @Override
183                     public void accept(P_OUT u) {
184                         if (predicate.test(u))
185                             downstream.accept(u);
186                     }
187                 };
188             }
189         };
190     }
191 
192     @Override
193     @SuppressWarnings("unchecked")
194     public final <R> Stream<R> map(Function<? super P_OUT, ? extends R> mapper) {
195         Objects.requireNonNull(mapper);
196         return new StatelessOp<P_OUT, R>(this, StreamShape.REFERENCE,
197                                      StreamOpFlag.NOT_SORTED | StreamOpFlag.NOT_DISTINCT) {
198             @Override
199             public Sink<P_OUT> opWrapSink(int flags, Sink<R> sink) {
200                 return new Sink.ChainedReference<P_OUT, R>(sink) {
201                     @Override
202                     public void accept(P_OUT u) {
203                         downstream.accept(mapper.apply(u));
204                     }
205                 };
206             }
207         };
208     }
209 
210     @Override
211     public final IntStream mapToInt(ToIntFunction<? super P_OUT> mapper) {
212         Objects.requireNonNull(mapper);
213         return new IntPipeline.StatelessOp<P_OUT>(this, StreamShape.REFERENCE,
214                                               StreamOpFlag.NOT_SORTED | StreamOpFlag.NOT_DISTINCT) {
215             @Override
216             // Android-changed: Make public, to match the method it's overriding.
217             public Sink<P_OUT> opWrapSink(int flags, Sink<Integer> sink) {
218                 return new Sink.ChainedReference<P_OUT, Integer>(sink) {
219                     @Override
220                     public void accept(P_OUT u) {
221                         downstream.accept(mapper.applyAsInt(u));
222                     }
223                 };
224             }
225         };
226     }
227 
228     @Override
229     public final LongStream mapToLong(ToLongFunction<? super P_OUT> mapper) {
230         Objects.requireNonNull(mapper);
231         return new LongPipeline.StatelessOp<P_OUT>(this, StreamShape.REFERENCE,
232                                       StreamOpFlag.NOT_SORTED | StreamOpFlag.NOT_DISTINCT) {
233             @Override
234             // Android-changed: Make public, to match the method it's overriding.
235             public Sink<P_OUT> opWrapSink(int flags, Sink<Long> sink) {
236                 return new Sink.ChainedReference<P_OUT, Long>(sink) {
237                     @Override
238                     public void accept(P_OUT u) {
239                         downstream.accept(mapper.applyAsLong(u));
240                     }
241                 };
242             }
243         };
244     }
245 
246     @Override
247     public final DoubleStream mapToDouble(ToDoubleFunction<? super P_OUT> mapper) {
248         Objects.requireNonNull(mapper);
249         return new DoublePipeline.StatelessOp<P_OUT>(this, StreamShape.REFERENCE,
250                                         StreamOpFlag.NOT_SORTED | StreamOpFlag.NOT_DISTINCT) {
251             @Override
252             // Android-changed: Make public, to match the method it's overriding.
253             public Sink<P_OUT> opWrapSink(int flags, Sink<Double> sink) {
254                 return new Sink.ChainedReference<P_OUT, Double>(sink) {
255                     @Override
256                     public void accept(P_OUT u) {
257                         downstream.accept(mapper.applyAsDouble(u));
258                     }
259                 };
260             }
261         };
262     }
263 
264     @Override
265     public final <R> Stream<R> flatMap(Function<? super P_OUT, ? extends Stream<? extends R>> mapper) {
266         Objects.requireNonNull(mapper);
267         // We can do better than this, by polling cancellationRequested when stream is infinite
268         return new StatelessOp<P_OUT, R>(this, StreamShape.REFERENCE,
269                                      StreamOpFlag.NOT_SORTED | StreamOpFlag.NOT_DISTINCT | StreamOpFlag.NOT_SIZED) {
270             @Override
271             public Sink<P_OUT> opWrapSink(int flags, Sink<R> sink) {
272                 return new Sink.ChainedReference<P_OUT, R>(sink) {
273                     @Override
274                     public void begin(long size) {
275                         downstream.begin(-1);
276                     }
277 
278                     @Override
279                     public void accept(P_OUT u) {
280                         try (Stream<? extends R> result = mapper.apply(u)) {
281                             // We can do better that this too; optimize for depth=0 case and just grab spliterator and forEach it
282                             if (result != null)
283                                 result.sequential().forEach(downstream);
284                         }
285                     }
286                 };
287             }
288         };
289     }
290 
291     @Override
292     public final IntStream flatMapToInt(Function<? super P_OUT, ? extends IntStream> mapper) {
293         Objects.requireNonNull(mapper);
294         // We can do better than this, by polling cancellationRequested when stream is infinite
295         return new IntPipeline.StatelessOp<P_OUT>(this, StreamShape.REFERENCE,
296                                               StreamOpFlag.NOT_SORTED | StreamOpFlag.NOT_DISTINCT | StreamOpFlag.NOT_SIZED) {
297             @Override
298             // Android-changed: Make public, to match the method it's overriding.
299             public Sink<P_OUT> opWrapSink(int flags, Sink<Integer> sink) {
300                 return new Sink.ChainedReference<P_OUT, Integer>(sink) {
301                     IntConsumer downstreamAsInt = downstream::accept;
302                     @Override
303                     public void begin(long size) {
304                         downstream.begin(-1);
305                     }
306 
307                     @Override
308                     public void accept(P_OUT u) {
309                         try (IntStream result = mapper.apply(u)) {
310                             // We can do better that this too; optimize for depth=0 case and just grab spliterator and forEach it
311                             if (result != null)
312                                 result.sequential().forEach(downstreamAsInt);
313                         }
314                     }
315                 };
316             }
317         };
318     }
319 
320     @Override
321     public final DoubleStream flatMapToDouble(Function<? super P_OUT, ? extends DoubleStream> mapper) {
322         Objects.requireNonNull(mapper);
323         // We can do better than this, by polling cancellationRequested when stream is infinite
324         return new DoublePipeline.StatelessOp<P_OUT>(this, StreamShape.REFERENCE,
325                                                      StreamOpFlag.NOT_SORTED | StreamOpFlag.NOT_DISTINCT | StreamOpFlag.NOT_SIZED) {
326             @Override
327             // Android-changed: Make public, to match the method it's overriding.
328             public Sink<P_OUT> opWrapSink(int flags, Sink<Double> sink) {
329                 return new Sink.ChainedReference<P_OUT, Double>(sink) {
330                     DoubleConsumer downstreamAsDouble = downstream::accept;
331                     @Override
332                     public void begin(long size) {
333                         downstream.begin(-1);
334                     }
335 
336                     @Override
337                     public void accept(P_OUT u) {
338                         try (DoubleStream result = mapper.apply(u)) {
339                             // We can do better that this too; optimize for depth=0 case and just grab spliterator and forEach it
340                             if (result != null)
341                                 result.sequential().forEach(downstreamAsDouble);
342                         }
343                     }
344                 };
345             }
346         };
347     }
348 
349     @Override
350     public final LongStream flatMapToLong(Function<? super P_OUT, ? extends LongStream> mapper) {
351         Objects.requireNonNull(mapper);
352         // We can do better than this, by polling cancellationRequested when stream is infinite
353         return new LongPipeline.StatelessOp<P_OUT>(this, StreamShape.REFERENCE,
354                                                    StreamOpFlag.NOT_SORTED | StreamOpFlag.NOT_DISTINCT | StreamOpFlag.NOT_SIZED) {
355             @Override
356             // Android-changed: Make public, to match the method it's overriding.
357             public Sink<P_OUT> opWrapSink(int flags, Sink<Long> sink) {
358                 return new Sink.ChainedReference<P_OUT, Long>(sink) {
359                     LongConsumer downstreamAsLong = downstream::accept;
360                     @Override
361                     public void begin(long size) {
362                         downstream.begin(-1);
363                     }
364 
365                     @Override
366                     public void accept(P_OUT u) {
367                         try (LongStream result = mapper.apply(u)) {
368                             // We can do better that this too; optimize for depth=0 case and just grab spliterator and forEach it
369                             if (result != null)
370                                 result.sequential().forEach(downstreamAsLong);
371                         }
372                     }
373                 };
374             }
375         };
376     }
377 
378     @Override
379     public final Stream<P_OUT> peek(Consumer<? super P_OUT> action) {
380         Objects.requireNonNull(action);
381         return new StatelessOp<P_OUT, P_OUT>(this, StreamShape.REFERENCE,
382                                      0) {
383             @Override
384             // Android-changed: Make public, to match the method it's overriding.
385             public Sink<P_OUT> opWrapSink(int flags, Sink<P_OUT> sink) {
386                 return new Sink.ChainedReference<P_OUT, P_OUT>(sink) {
387                     @Override
388                     public void accept(P_OUT u) {
389                         action.accept(u);
390                         downstream.accept(u);
391                     }
392                 };
393             }
394         };
395     }
396 
397     // Stateful intermediate operations from Stream
398 
399     @Override
400     public final Stream<P_OUT> distinct() {
401         return DistinctOps.makeRef(this);
402     }
403 
404     @Override
405     public final Stream<P_OUT> sorted() {
406         return SortedOps.makeRef(this);
407     }
408 
409     @Override
410     public final Stream<P_OUT> sorted(Comparator<? super P_OUT> comparator) {
411         return SortedOps.makeRef(this, comparator);
412     }
413 
414     @Override
415     public final Stream<P_OUT> limit(long maxSize) {
416         if (maxSize < 0)
417             throw new IllegalArgumentException(Long.toString(maxSize));
418         return SliceOps.makeRef(this, 0, maxSize);
419     }
420 
421     @Override
422     public final Stream<P_OUT> skip(long n) {
423         if (n < 0)
424             throw new IllegalArgumentException(Long.toString(n));
425         if (n == 0)
426             return this;
427         else
428             return SliceOps.makeRef(this, n, -1);
429     }
430 
431     // Terminal operations from Stream
432 
433     @Override
434     public void forEach(Consumer<? super P_OUT> action) {
435         evaluate(ForEachOps.makeRef(action, false));
436     }
437 
438     @Override
439     public void forEachOrdered(Consumer<? super P_OUT> action) {
440         evaluate(ForEachOps.makeRef(action, true));
441     }
442 
443     @Override
444     @SuppressWarnings("unchecked")
445     public final <A> A[] toArray(IntFunction<A[]> generator) {
446         // Since A has no relation to U (not possible to declare that A is an upper bound of U)
447         // there will be no static type checking.
448         // Therefore use a raw type and assume A == U rather than propagating the separation of A and U
449         // throughout the code-base.
450         // The runtime type of U is never checked for equality with the component type of the runtime type of A[].
451         // Runtime checking will be performed when an element is stored in A[], thus if A is not a
452         // super type of U an ArrayStoreException will be thrown.
453         @SuppressWarnings("rawtypes")
454         IntFunction rawGenerator = (IntFunction) generator;
455         // Android-changed: Eclipse compiler requires explicit (Node<A[]>) cast (b/29399275).
456         return (A[]) Nodes.flatten((Node<A[]>) evaluateToArrayNode(rawGenerator), rawGenerator)
457                 .asArray(rawGenerator);
458     }
459 
460     @Override
461     public final Object[] toArray() {
462         return toArray(Object[]::new);
463     }
464 
465     @Override
466     public final boolean anyMatch(Predicate<? super P_OUT> predicate) {
467         return evaluate(MatchOps.makeRef(predicate, MatchOps.MatchKind.ANY));
468     }
469 
470     @Override
471     public final boolean allMatch(Predicate<? super P_OUT> predicate) {
472         return evaluate(MatchOps.makeRef(predicate, MatchOps.MatchKind.ALL));
473     }
474 
475     @Override
476     public final boolean noneMatch(Predicate<? super P_OUT> predicate) {
477         return evaluate(MatchOps.makeRef(predicate, MatchOps.MatchKind.NONE));
478     }
479 
480     @Override
481     public final Optional<P_OUT> findFirst() {
482         return evaluate(FindOps.makeRef(true));
483     }
484 
485     @Override
486     public final Optional<P_OUT> findAny() {
487         return evaluate(FindOps.makeRef(false));
488     }
489 
490     @Override
491     public final P_OUT reduce(final P_OUT identity, final BinaryOperator<P_OUT> accumulator) {
492         return evaluate(ReduceOps.makeRef(identity, accumulator, accumulator));
493     }
494 
495     @Override
496     public final Optional<P_OUT> reduce(BinaryOperator<P_OUT> accumulator) {
497         return evaluate(ReduceOps.makeRef(accumulator));
498     }
499 
500     @Override
501     public final <R> R reduce(R identity, BiFunction<R, ? super P_OUT, R> accumulator, BinaryOperator<R> combiner) {
502         return evaluate(ReduceOps.makeRef(identity, accumulator, combiner));
503     }
504 
505     @Override
506     @SuppressWarnings("unchecked")
507     public final <R, A> R collect(Collector<? super P_OUT, A, R> collector) {
508         A container;
509         if (isParallel()
510                 && (collector.characteristics().contains(Collector.Characteristics.CONCURRENT))
511                 && (!isOrdered() || collector.characteristics().contains(Collector.Characteristics.UNORDERED))) {
512             container = collector.supplier().get();
513             BiConsumer<A, ? super P_OUT> accumulator = collector.accumulator();
514             forEach(u -> accumulator.accept(container, u));
515         }
516         else {
517             container = evaluate(ReduceOps.makeRef(collector));
518         }
519         return collector.characteristics().contains(Collector.Characteristics.IDENTITY_FINISH)
520                ? (R) container
521                : collector.finisher().apply(container);
522     }
523 
524     @Override
525     public final <R> R collect(Supplier<R> supplier,
526                                BiConsumer<R, ? super P_OUT> accumulator,
527                                BiConsumer<R, R> combiner) {
528         return evaluate(ReduceOps.makeRef(supplier, accumulator, combiner));
529     }
530 
531     @Override
532     public final Optional<P_OUT> max(Comparator<? super P_OUT> comparator) {
533         return reduce(BinaryOperator.maxBy(comparator));
534     }
535 
536     @Override
537     public final Optional<P_OUT> min(Comparator<? super P_OUT> comparator) {
538         return reduce(BinaryOperator.minBy(comparator));
539 
540     }
541 
542     @Override
543     public final long count() {
544         return mapToLong(e -> 1L).sum();
545     }
546 
547 
548     //
549 
550     /**
551      * Source stage of a ReferencePipeline.
552      *
553      * @param <E_IN> type of elements in the upstream source
554      * @param <E_OUT> type of elements in produced by this stage
555      * @since 1.8
556      * @hide Visible for CTS testing only (OpenJDK8 tests).
557      */
558     // Android-changed: Made public for CTS tests only.
559     public static class Head<E_IN, E_OUT> extends ReferencePipeline<E_IN, E_OUT> {
560         /**
561          * Constructor for the source stage of a Stream.
562          *
563          * @param source {@code Supplier<Spliterator>} describing the stream
564          *               source
565          * @param sourceFlags the source flags for the stream source, described
566          *                    in {@link StreamOpFlag}
567          */
568         // Android-changed: Made public for CTS tests only.
569         public Head(Supplier<? extends Spliterator<?>> source,
570              int sourceFlags, boolean parallel) {
571             super(source, sourceFlags, parallel);
572         }
573 
574         /**
575          * Constructor for the source stage of a Stream.
576          *
577          * @param source {@code Spliterator} describing the stream source
578          * @param sourceFlags the source flags for the stream source, described
579          *                    in {@link StreamOpFlag}
580          */
581         // Android-changed: Made public for CTS tests only.
582         public Head(Spliterator<?> source,
583              int sourceFlags, boolean parallel) {
584             super(source, sourceFlags, parallel);
585         }
586 
587         @Override
588         // Android-changed: Make public, to match the method it's overriding.
589         public final boolean opIsStateful() {
590             throw new UnsupportedOperationException();
591         }
592 
593         @Override
594         // Android-changed: Make public, to match the method it's overriding.
595         public final Sink<E_IN> opWrapSink(int flags, Sink<E_OUT> sink) {
596             throw new UnsupportedOperationException();
597         }
598 
599         // Optimized sequential terminal operations for the head of the pipeline
600 
601         @Override
602         public void forEach(Consumer<? super E_OUT> action) {
603             if (!isParallel()) {
604                 sourceStageSpliterator().forEachRemaining(action);
605             }
606             else {
607                 super.forEach(action);
608             }
609         }
610 
611         @Override
612         public void forEachOrdered(Consumer<? super E_OUT> action) {
613             if (!isParallel()) {
614                 sourceStageSpliterator().forEachRemaining(action);
615             }
616             else {
617                 super.forEachOrdered(action);
618             }
619         }
620     }
621 
622     /**
623      * Base class for a stateless intermediate stage of a Stream.
624      *
625      * @param <E_IN> type of elements in the upstream source
626      * @param <E_OUT> type of elements in produced by this stage
627      * @since 1.8
628      * @hide Visible for CTS testing only (OpenJDK8 tests).
629      */
630     // Android-changed: Made public for CTS tests only.
631     public abstract static class StatelessOp<E_IN, E_OUT>
632             extends ReferencePipeline<E_IN, E_OUT> {
633         /**
634          * Construct a new Stream by appending a stateless intermediate
635          * operation to an existing stream.
636          *
637          * @param upstream The upstream pipeline stage
638          * @param inputShape The stream shape for the upstream pipeline stage
639          * @param opFlags Operation flags for the new stage
640          */
641         // Android-changed: Made public for CTS tests only.
642         public StatelessOp(AbstractPipeline<?, E_IN, ?> upstream,
643                     StreamShape inputShape,
644                     int opFlags) {
645             super(upstream, opFlags);
646             assert upstream.getOutputShape() == inputShape;
647         }
648 
649         @Override
650         // Android-changed: Make public, to match the method it's overriding.
651         public final boolean opIsStateful() {
652             return false;
653         }
654     }
655 
656     /**
657      * Base class for a stateful intermediate stage of a Stream.
658      *
659      * @param <E_IN> type of elements in the upstream source
660      * @param <E_OUT> type of elements in produced by this stage
661      * @since 1.8
662      * @hide Visible for CTS testing only (OpenJDK8 tests).
663      */
664     // Android-changed: Made public for CTS tests only.
665     public abstract static class StatefulOp<E_IN, E_OUT>
666             extends ReferencePipeline<E_IN, E_OUT> {
667         /**
668          * Construct a new Stream by appending a stateful intermediate operation
669          * to an existing stream.
670          * @param upstream The upstream pipeline stage
671          * @param inputShape The stream shape for the upstream pipeline stage
672          * @param opFlags Operation flags for the new stage
673          */
674         // Android-changed: Made public for CTS tests only.
675         public StatefulOp(AbstractPipeline<?, E_IN, ?> upstream,
676                    StreamShape inputShape,
677                    int opFlags) {
678             super(upstream, opFlags);
679             assert upstream.getOutputShape() == inputShape;
680         }
681 
682         @Override
683         // Android-changed: Make public, to match the method it's overriding.
684         public final boolean opIsStateful() {
685             return true;
686         }
687 
688         @Override
689         // Android-changed: Make public, to match the method it's overriding.
690         public abstract <P_IN> Node<E_OUT> opEvaluateParallel(PipelineHelper<E_OUT> helper,
691                                                        Spliterator<P_IN> spliterator,
692                                                        IntFunction<E_OUT[]> generator);
693     }
694 }
695