1 /* 2 * Copyright (c) 2012, 2021, 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.Objects; 29 import java.util.Spliterator; 30 import java.util.concurrent.ConcurrentHashMap; 31 import java.util.concurrent.atomic.AtomicLong; 32 import java.util.function.BooleanSupplier; 33 import java.util.function.Consumer; 34 import java.util.function.DoubleConsumer; 35 import java.util.function.DoubleSupplier; 36 import java.util.function.IntConsumer; 37 import java.util.function.IntSupplier; 38 import java.util.function.LongConsumer; 39 import java.util.function.LongSupplier; 40 import java.util.function.Supplier; 41 42 /** 43 * Spliterator implementations for wrapping and delegating spliterators, used 44 * in the implementation of the {@link Stream#spliterator()} method. 45 * 46 * @since 1.8 47 */ 48 class StreamSpliterators { 49 50 /** 51 * Abstract wrapping spliterator that binds to the spliterator of a 52 * pipeline helper on first operation. 53 * 54 * <p>This spliterator is not late-binding and will bind to the source 55 * spliterator when first operated on. 56 * 57 * <p>A wrapping spliterator produced from a sequential stream 58 * cannot be split if there are stateful operations present. 59 */ 60 private abstract static class AbstractWrappingSpliterator<P_IN, P_OUT, 61 T_BUFFER extends AbstractSpinedBuffer> 62 implements Spliterator<P_OUT> { 63 64 // @@@ Detect if stateful operations are present or not 65 // If not then can split otherwise cannot 66 67 /** 68 * True if this spliterator supports splitting 69 */ 70 final boolean isParallel; 71 72 final PipelineHelper<P_OUT> ph; 73 74 /** 75 * Supplier for the source spliterator. Client provides either a 76 * spliterator or a supplier. 77 */ 78 private Supplier<Spliterator<P_IN>> spliteratorSupplier; 79 80 /** 81 * Source spliterator. Either provided from client or obtained from 82 * supplier. 83 */ 84 Spliterator<P_IN> spliterator; 85 86 /** 87 * Sink chain for the downstream stages of the pipeline, ultimately 88 * leading to the buffer. Used during partial traversal. 89 */ 90 Sink<P_IN> bufferSink; 91 92 /** 93 * A function that advances one element of the spliterator, pushing 94 * it to bufferSink. Returns whether any elements were processed. 95 * Used during partial traversal. 96 */ 97 BooleanSupplier pusher; 98 99 /** Next element to consume from the buffer, used during partial traversal */ 100 long nextToConsume; 101 102 /** Buffer into which elements are pushed. Used during partial traversal. */ 103 T_BUFFER buffer; 104 105 /** 106 * True if full traversal has occurred (with possible cancellation). 107 * If doing a partial traversal, there may be still elements in buffer. 108 */ 109 boolean finished; 110 111 /** 112 * Construct an AbstractWrappingSpliterator from a 113 * {@code Supplier<Spliterator>}. 114 */ AbstractWrappingSpliterator(PipelineHelper<P_OUT> ph, Supplier<Spliterator<P_IN>> spliteratorSupplier, boolean parallel)115 AbstractWrappingSpliterator(PipelineHelper<P_OUT> ph, 116 Supplier<Spliterator<P_IN>> spliteratorSupplier, 117 boolean parallel) { 118 this.ph = ph; 119 this.spliteratorSupplier = spliteratorSupplier; 120 this.spliterator = null; 121 this.isParallel = parallel; 122 } 123 124 /** 125 * Construct an AbstractWrappingSpliterator from a 126 * {@code Spliterator}. 127 */ AbstractWrappingSpliterator(PipelineHelper<P_OUT> ph, Spliterator<P_IN> spliterator, boolean parallel)128 AbstractWrappingSpliterator(PipelineHelper<P_OUT> ph, 129 Spliterator<P_IN> spliterator, 130 boolean parallel) { 131 this.ph = ph; 132 this.spliteratorSupplier = null; 133 this.spliterator = spliterator; 134 this.isParallel = parallel; 135 } 136 137 /** 138 * Called before advancing to set up spliterator, if needed. 139 */ init()140 final void init() { 141 if (spliterator == null) { 142 spliterator = spliteratorSupplier.get(); 143 spliteratorSupplier = null; 144 } 145 } 146 147 /** 148 * Get an element from the source, pushing it into the sink chain, 149 * setting up the buffer if needed 150 * @return whether there are elements to consume from the buffer 151 */ doAdvance()152 final boolean doAdvance() { 153 if (buffer == null) { 154 if (finished) 155 return false; 156 157 init(); 158 initPartialTraversalState(); 159 nextToConsume = 0; 160 bufferSink.begin(spliterator.getExactSizeIfKnown()); 161 return fillBuffer(); 162 } 163 else { 164 ++nextToConsume; 165 boolean hasNext = nextToConsume < buffer.count(); 166 if (!hasNext) { 167 nextToConsume = 0; 168 buffer.clear(); 169 hasNext = fillBuffer(); 170 } 171 return hasNext; 172 } 173 } 174 175 /** 176 * Invokes the shape-specific constructor with the provided arguments 177 * and returns the result. 178 */ 179 abstract AbstractWrappingSpliterator<P_IN, P_OUT, ?> wrap(Spliterator<P_IN> s); 180 181 /** 182 * Initializes buffer, sink chain, and pusher for a shape-specific 183 * implementation. 184 */ 185 abstract void initPartialTraversalState(); 186 187 @Override 188 public Spliterator<P_OUT> trySplit() { 189 if (isParallel && buffer == null && !finished) { 190 init(); 191 192 Spliterator<P_IN> split = spliterator.trySplit(); 193 return (split == null) ? null : wrap(split); 194 } 195 else 196 return null; 197 } 198 199 /** 200 * If the buffer is empty, push elements into the sink chain until 201 * the source is empty or cancellation is requested. 202 * @return whether there are elements to consume from the buffer 203 */ 204 private boolean fillBuffer() { 205 while (buffer.count() == 0) { 206 if (bufferSink.cancellationRequested() || !pusher.getAsBoolean()) { 207 if (finished) 208 return false; 209 else { 210 bufferSink.end(); // might trigger more elements 211 finished = true; 212 } 213 } 214 } 215 return true; 216 } 217 218 @Override 219 public final long estimateSize() { 220 long exactSizeIfKnown = getExactSizeIfKnown(); 221 // Use the estimate of the wrapped spliterator 222 // Note this may not be accurate if there are filter/flatMap 223 // operations filtering or adding elements to the stream 224 return exactSizeIfKnown == -1 ? spliterator.estimateSize() : exactSizeIfKnown; 225 } 226 227 @Override 228 public final long getExactSizeIfKnown() { 229 init(); 230 return ph.exactOutputSizeIfKnown(spliterator); 231 } 232 233 @Override 234 public final int characteristics() { 235 init(); 236 237 // Get the characteristics from the pipeline 238 int c = StreamOpFlag.toCharacteristics(StreamOpFlag.toStreamFlags(ph.getStreamAndOpFlags())); 239 240 // Mask off the size and uniform characteristics and replace with 241 // those of the spliterator 242 // Note that a non-uniform spliterator can change from something 243 // with an exact size to an estimate for a sub-split, for example 244 // with HashSet where the size is known at the top level spliterator 245 // but for sub-splits only an estimate is known 246 if ((c & Spliterator.SIZED) != 0) { 247 c &= ~(Spliterator.SIZED | Spliterator.SUBSIZED); 248 c |= (spliterator.characteristics() & (Spliterator.SIZED | Spliterator.SUBSIZED)); 249 } 250 251 return c; 252 } 253 254 @Override 255 public Comparator<? super P_OUT> getComparator() { 256 if (!hasCharacteristics(SORTED)) 257 throw new IllegalStateException(); 258 return null; 259 } 260 261 @Override 262 public final String toString() { 263 return String.format("%s[%s]", getClass().getName(), spliterator); 264 } 265 } 266 267 static final class WrappingSpliterator<P_IN, P_OUT> 268 extends AbstractWrappingSpliterator<P_IN, P_OUT, SpinedBuffer<P_OUT>> { 269 270 WrappingSpliterator(PipelineHelper<P_OUT> ph, 271 Supplier<Spliterator<P_IN>> supplier, 272 boolean parallel) { 273 super(ph, supplier, parallel); 274 } 275 276 WrappingSpliterator(PipelineHelper<P_OUT> ph, 277 Spliterator<P_IN> spliterator, 278 boolean parallel) { 279 super(ph, spliterator, parallel); 280 } 281 282 @Override 283 WrappingSpliterator<P_IN, P_OUT> wrap(Spliterator<P_IN> s) { 284 return new WrappingSpliterator<>(ph, s, isParallel); 285 } 286 287 @Override 288 void initPartialTraversalState() { 289 SpinedBuffer<P_OUT> b = new SpinedBuffer<>(); 290 buffer = b; 291 bufferSink = ph.wrapSink(b::accept); 292 pusher = () -> spliterator.tryAdvance(bufferSink); 293 } 294 295 @Override tryAdvance(Consumer<? super P_OUT> consumer)296 public boolean tryAdvance(Consumer<? super P_OUT> consumer) { 297 Objects.requireNonNull(consumer); 298 boolean hasNext = doAdvance(); 299 if (hasNext) 300 consumer.accept(buffer.get(nextToConsume)); 301 return hasNext; 302 } 303 304 @Override forEachRemaining(Consumer<? super P_OUT> consumer)305 public void forEachRemaining(Consumer<? super P_OUT> consumer) { 306 if (buffer == null && !finished) { 307 Objects.requireNonNull(consumer); 308 init(); 309 310 ph.wrapAndCopyInto((Sink<P_OUT>) consumer::accept, spliterator); 311 finished = true; 312 } 313 else { 314 do { } while (tryAdvance(consumer)); 315 } 316 } 317 } 318 319 static final class IntWrappingSpliterator<P_IN> 320 extends AbstractWrappingSpliterator<P_IN, Integer, SpinedBuffer.OfInt> 321 implements Spliterator.OfInt { 322 IntWrappingSpliterator(PipelineHelper<Integer> ph, Supplier<Spliterator<P_IN>> supplier, boolean parallel)323 IntWrappingSpliterator(PipelineHelper<Integer> ph, 324 Supplier<Spliterator<P_IN>> supplier, 325 boolean parallel) { 326 super(ph, supplier, parallel); 327 } 328 IntWrappingSpliterator(PipelineHelper<Integer> ph, Spliterator<P_IN> spliterator, boolean parallel)329 IntWrappingSpliterator(PipelineHelper<Integer> ph, 330 Spliterator<P_IN> spliterator, 331 boolean parallel) { 332 super(ph, spliterator, parallel); 333 } 334 335 @Override wrap(Spliterator<P_IN> s)336 AbstractWrappingSpliterator<P_IN, Integer, ?> wrap(Spliterator<P_IN> s) { 337 return new IntWrappingSpliterator<>(ph, s, isParallel); 338 } 339 340 @Override initPartialTraversalState()341 void initPartialTraversalState() { 342 SpinedBuffer.OfInt b = new SpinedBuffer.OfInt(); 343 buffer = b; 344 bufferSink = ph.wrapSink((Sink.OfInt) b::accept); 345 pusher = () -> spliterator.tryAdvance(bufferSink); 346 } 347 348 @Override trySplit()349 public Spliterator.OfInt trySplit() { 350 return (Spliterator.OfInt) super.trySplit(); 351 } 352 353 @Override tryAdvance(IntConsumer consumer)354 public boolean tryAdvance(IntConsumer consumer) { 355 Objects.requireNonNull(consumer); 356 boolean hasNext = doAdvance(); 357 if (hasNext) 358 consumer.accept(buffer.get(nextToConsume)); 359 return hasNext; 360 } 361 362 @Override forEachRemaining(IntConsumer consumer)363 public void forEachRemaining(IntConsumer consumer) { 364 if (buffer == null && !finished) { 365 Objects.requireNonNull(consumer); 366 init(); 367 368 ph.wrapAndCopyInto((Sink.OfInt) consumer::accept, spliterator); 369 finished = true; 370 } 371 else { 372 do { } while (tryAdvance(consumer)); 373 } 374 } 375 } 376 377 static final class LongWrappingSpliterator<P_IN> 378 extends AbstractWrappingSpliterator<P_IN, Long, SpinedBuffer.OfLong> 379 implements Spliterator.OfLong { 380 LongWrappingSpliterator(PipelineHelper<Long> ph, Supplier<Spliterator<P_IN>> supplier, boolean parallel)381 LongWrappingSpliterator(PipelineHelper<Long> ph, 382 Supplier<Spliterator<P_IN>> supplier, 383 boolean parallel) { 384 super(ph, supplier, parallel); 385 } 386 LongWrappingSpliterator(PipelineHelper<Long> ph, Spliterator<P_IN> spliterator, boolean parallel)387 LongWrappingSpliterator(PipelineHelper<Long> ph, 388 Spliterator<P_IN> spliterator, 389 boolean parallel) { 390 super(ph, spliterator, parallel); 391 } 392 393 @Override wrap(Spliterator<P_IN> s)394 AbstractWrappingSpliterator<P_IN, Long, ?> wrap(Spliterator<P_IN> s) { 395 return new LongWrappingSpliterator<>(ph, s, isParallel); 396 } 397 398 @Override initPartialTraversalState()399 void initPartialTraversalState() { 400 SpinedBuffer.OfLong b = new SpinedBuffer.OfLong(); 401 buffer = b; 402 bufferSink = ph.wrapSink((Sink.OfLong) b::accept); 403 pusher = () -> spliterator.tryAdvance(bufferSink); 404 } 405 406 @Override trySplit()407 public Spliterator.OfLong trySplit() { 408 return (Spliterator.OfLong) super.trySplit(); 409 } 410 411 @Override tryAdvance(LongConsumer consumer)412 public boolean tryAdvance(LongConsumer consumer) { 413 Objects.requireNonNull(consumer); 414 boolean hasNext = doAdvance(); 415 if (hasNext) 416 consumer.accept(buffer.get(nextToConsume)); 417 return hasNext; 418 } 419 420 @Override forEachRemaining(LongConsumer consumer)421 public void forEachRemaining(LongConsumer consumer) { 422 if (buffer == null && !finished) { 423 Objects.requireNonNull(consumer); 424 init(); 425 426 ph.wrapAndCopyInto((Sink.OfLong) consumer::accept, spliterator); 427 finished = true; 428 } 429 else { 430 do { } while (tryAdvance(consumer)); 431 } 432 } 433 } 434 435 static final class DoubleWrappingSpliterator<P_IN> 436 extends AbstractWrappingSpliterator<P_IN, Double, SpinedBuffer.OfDouble> 437 implements Spliterator.OfDouble { 438 DoubleWrappingSpliterator(PipelineHelper<Double> ph, Supplier<Spliterator<P_IN>> supplier, boolean parallel)439 DoubleWrappingSpliterator(PipelineHelper<Double> ph, 440 Supplier<Spliterator<P_IN>> supplier, 441 boolean parallel) { 442 super(ph, supplier, parallel); 443 } 444 DoubleWrappingSpliterator(PipelineHelper<Double> ph, Spliterator<P_IN> spliterator, boolean parallel)445 DoubleWrappingSpliterator(PipelineHelper<Double> ph, 446 Spliterator<P_IN> spliterator, 447 boolean parallel) { 448 super(ph, spliterator, parallel); 449 } 450 451 @Override wrap(Spliterator<P_IN> s)452 AbstractWrappingSpliterator<P_IN, Double, ?> wrap(Spliterator<P_IN> s) { 453 return new DoubleWrappingSpliterator<>(ph, s, isParallel); 454 } 455 456 @Override initPartialTraversalState()457 void initPartialTraversalState() { 458 SpinedBuffer.OfDouble b = new SpinedBuffer.OfDouble(); 459 buffer = b; 460 bufferSink = ph.wrapSink((Sink.OfDouble) b::accept); 461 pusher = () -> spliterator.tryAdvance(bufferSink); 462 } 463 464 @Override trySplit()465 public Spliterator.OfDouble trySplit() { 466 return (Spliterator.OfDouble) super.trySplit(); 467 } 468 469 @Override tryAdvance(DoubleConsumer consumer)470 public boolean tryAdvance(DoubleConsumer consumer) { 471 Objects.requireNonNull(consumer); 472 boolean hasNext = doAdvance(); 473 if (hasNext) 474 consumer.accept(buffer.get(nextToConsume)); 475 return hasNext; 476 } 477 478 @Override forEachRemaining(DoubleConsumer consumer)479 public void forEachRemaining(DoubleConsumer consumer) { 480 if (buffer == null && !finished) { 481 Objects.requireNonNull(consumer); 482 init(); 483 484 ph.wrapAndCopyInto((Sink.OfDouble) consumer::accept, spliterator); 485 finished = true; 486 } 487 else { 488 do { } while (tryAdvance(consumer)); 489 } 490 } 491 } 492 493 /** 494 * Spliterator implementation that delegates to an underlying spliterator, 495 * acquiring the spliterator from a {@code Supplier<Spliterator>} on the 496 * first call to any spliterator method. 497 * @param <T> 498 */ 499 static class DelegatingSpliterator<T, T_SPLITR extends Spliterator<T>> 500 implements Spliterator<T> { 501 private final Supplier<? extends T_SPLITR> supplier; 502 503 private T_SPLITR s; 504 DelegatingSpliterator(Supplier<? extends T_SPLITR> supplier)505 DelegatingSpliterator(Supplier<? extends T_SPLITR> supplier) { 506 this.supplier = supplier; 507 } 508 get()509 T_SPLITR get() { 510 if (s == null) { 511 s = supplier.get(); 512 } 513 return s; 514 } 515 516 @Override 517 @SuppressWarnings("unchecked") trySplit()518 public T_SPLITR trySplit() { 519 return (T_SPLITR) get().trySplit(); 520 } 521 522 @Override tryAdvance(Consumer<? super T> consumer)523 public boolean tryAdvance(Consumer<? super T> consumer) { 524 return get().tryAdvance(consumer); 525 } 526 527 @Override forEachRemaining(Consumer<? super T> consumer)528 public void forEachRemaining(Consumer<? super T> consumer) { 529 get().forEachRemaining(consumer); 530 } 531 532 @Override estimateSize()533 public long estimateSize() { 534 return get().estimateSize(); 535 } 536 537 @Override characteristics()538 public int characteristics() { 539 return get().characteristics(); 540 } 541 542 @Override getComparator()543 public Comparator<? super T> getComparator() { 544 return get().getComparator(); 545 } 546 547 @Override getExactSizeIfKnown()548 public long getExactSizeIfKnown() { 549 return get().getExactSizeIfKnown(); 550 } 551 552 @Override toString()553 public String toString() { 554 return getClass().getName() + "[" + get() + "]"; 555 } 556 557 static class OfPrimitive<T, T_CONS, T_SPLITR extends Spliterator.OfPrimitive<T, T_CONS, T_SPLITR>> 558 extends DelegatingSpliterator<T, T_SPLITR> 559 implements Spliterator.OfPrimitive<T, T_CONS, T_SPLITR> { OfPrimitive(Supplier<? extends T_SPLITR> supplier)560 OfPrimitive(Supplier<? extends T_SPLITR> supplier) { 561 super(supplier); 562 } 563 564 @Override tryAdvance(T_CONS consumer)565 public boolean tryAdvance(T_CONS consumer) { 566 return get().tryAdvance(consumer); 567 } 568 569 @Override forEachRemaining(T_CONS consumer)570 public void forEachRemaining(T_CONS consumer) { 571 get().forEachRemaining(consumer); 572 } 573 } 574 575 static final class OfInt 576 extends OfPrimitive<Integer, IntConsumer, Spliterator.OfInt> 577 implements Spliterator.OfInt { 578 OfInt(Supplier<Spliterator.OfInt> supplier)579 OfInt(Supplier<Spliterator.OfInt> supplier) { 580 super(supplier); 581 } 582 } 583 584 static final class OfLong 585 extends OfPrimitive<Long, LongConsumer, Spliterator.OfLong> 586 implements Spliterator.OfLong { 587 OfLong(Supplier<Spliterator.OfLong> supplier)588 OfLong(Supplier<Spliterator.OfLong> supplier) { 589 super(supplier); 590 } 591 } 592 593 static final class OfDouble 594 extends OfPrimitive<Double, DoubleConsumer, Spliterator.OfDouble> 595 implements Spliterator.OfDouble { 596 OfDouble(Supplier<Spliterator.OfDouble> supplier)597 OfDouble(Supplier<Spliterator.OfDouble> supplier) { 598 super(supplier); 599 } 600 } 601 } 602 603 /** 604 * A slice Spliterator from a source Spliterator that reports 605 * {@code SUBSIZED}. 606 * 607 */ 608 abstract static class SliceSpliterator<T, T_SPLITR extends Spliterator<T>> { 609 // The start index of the slice 610 final long sliceOrigin; 611 // One past the last index of the slice 612 final long sliceFence; 613 614 // The spliterator to slice 615 T_SPLITR s; 616 // current (absolute) index, modified on advance/split 617 long index; 618 // one past last (absolute) index or sliceFence, which ever is smaller 619 long fence; 620 SliceSpliterator(T_SPLITR s, long sliceOrigin, long sliceFence, long origin, long fence)621 SliceSpliterator(T_SPLITR s, long sliceOrigin, long sliceFence, long origin, long fence) { 622 assert s.hasCharacteristics(Spliterator.SUBSIZED); 623 this.s = s; 624 this.sliceOrigin = sliceOrigin; 625 this.sliceFence = sliceFence; 626 this.index = origin; 627 this.fence = fence; 628 } 629 makeSpliterator(T_SPLITR s, long sliceOrigin, long sliceFence, long origin, long fence)630 protected abstract T_SPLITR makeSpliterator(T_SPLITR s, long sliceOrigin, long sliceFence, long origin, long fence); 631 trySplit()632 public T_SPLITR trySplit() { 633 if (sliceOrigin >= fence) 634 return null; 635 636 if (index >= fence) 637 return null; 638 639 // Keep splitting until the left and right splits intersect with the slice 640 // thereby ensuring the size estimate decreases. 641 // This also avoids creating empty spliterators which can result in 642 // existing and additionally created F/J tasks that perform 643 // redundant work on no elements. 644 while (true) { 645 @SuppressWarnings("unchecked") 646 T_SPLITR leftSplit = (T_SPLITR) s.trySplit(); 647 if (leftSplit == null) 648 return null; 649 650 long leftSplitFenceUnbounded = index + leftSplit.estimateSize(); 651 long leftSplitFence = Math.min(leftSplitFenceUnbounded, sliceFence); 652 if (sliceOrigin >= leftSplitFence) { 653 // The left split does not intersect with, and is to the left of, the slice 654 // The right split does intersect 655 // Discard the left split and split further with the right split 656 index = leftSplitFence; 657 } 658 else if (leftSplitFence >= sliceFence) { 659 // The right split does not intersect with, and is to the right of, the slice 660 // The left split does intersect 661 // Discard the right split and split further with the left split 662 s = leftSplit; 663 fence = leftSplitFence; 664 } 665 else if (index >= sliceOrigin && leftSplitFenceUnbounded <= sliceFence) { 666 // The left split is contained within the slice, return the underlying left split 667 // Right split is contained within or intersects with the slice 668 index = leftSplitFence; 669 return leftSplit; 670 } else { 671 // The left split intersects with the slice 672 // Right split is contained within or intersects with the slice 673 return makeSpliterator(leftSplit, sliceOrigin, sliceFence, index, index = leftSplitFence); 674 } 675 } 676 } 677 estimateSize()678 public long estimateSize() { 679 return (sliceOrigin < fence) 680 ? fence - Math.max(sliceOrigin, index) : 0; 681 } 682 characteristics()683 public int characteristics() { 684 return s.characteristics(); 685 } 686 687 static final class OfRef<T> 688 extends SliceSpliterator<T, Spliterator<T>> 689 implements Spliterator<T> { 690 OfRef(Spliterator<T> s, long sliceOrigin, long sliceFence)691 OfRef(Spliterator<T> s, long sliceOrigin, long sliceFence) { 692 this(s, sliceOrigin, sliceFence, 0, Math.min(s.estimateSize(), sliceFence)); 693 } 694 OfRef(Spliterator<T> s, long sliceOrigin, long sliceFence, long origin, long fence)695 private OfRef(Spliterator<T> s, 696 long sliceOrigin, long sliceFence, long origin, long fence) { 697 super(s, sliceOrigin, sliceFence, origin, fence); 698 } 699 700 @Override makeSpliterator(Spliterator<T> s, long sliceOrigin, long sliceFence, long origin, long fence)701 protected Spliterator<T> makeSpliterator(Spliterator<T> s, 702 long sliceOrigin, long sliceFence, 703 long origin, long fence) { 704 return new OfRef<>(s, sliceOrigin, sliceFence, origin, fence); 705 } 706 707 @Override tryAdvance(Consumer<? super T> action)708 public boolean tryAdvance(Consumer<? super T> action) { 709 Objects.requireNonNull(action); 710 711 if (sliceOrigin >= fence) 712 return false; 713 714 while (sliceOrigin > index) { 715 s.tryAdvance(e -> {}); 716 index++; 717 } 718 719 if (index >= fence) 720 return false; 721 722 index++; 723 return s.tryAdvance(action); 724 } 725 726 @Override forEachRemaining(Consumer<? super T> action)727 public void forEachRemaining(Consumer<? super T> action) { 728 Objects.requireNonNull(action); 729 730 if (sliceOrigin >= fence) 731 return; 732 733 if (index >= fence) 734 return; 735 736 if (index >= sliceOrigin && (index + s.estimateSize()) <= sliceFence) { 737 // The spliterator is contained within the slice 738 s.forEachRemaining(action); 739 index = fence; 740 } else { 741 // The spliterator intersects with the slice 742 while (sliceOrigin > index) { 743 s.tryAdvance(e -> {}); 744 index++; 745 } 746 // Traverse elements up to the fence 747 for (;index < fence; index++) { 748 s.tryAdvance(action); 749 } 750 } 751 } 752 } 753 754 abstract static class OfPrimitive<T, 755 T_SPLITR extends Spliterator.OfPrimitive<T, T_CONS, T_SPLITR>, 756 T_CONS> 757 extends SliceSpliterator<T, T_SPLITR> 758 implements Spliterator.OfPrimitive<T, T_CONS, T_SPLITR> { 759 OfPrimitive(T_SPLITR s, long sliceOrigin, long sliceFence)760 OfPrimitive(T_SPLITR s, long sliceOrigin, long sliceFence) { 761 this(s, sliceOrigin, sliceFence, 0, Math.min(s.estimateSize(), sliceFence)); 762 } 763 OfPrimitive(T_SPLITR s, long sliceOrigin, long sliceFence, long origin, long fence)764 private OfPrimitive(T_SPLITR s, 765 long sliceOrigin, long sliceFence, long origin, long fence) { 766 super(s, sliceOrigin, sliceFence, origin, fence); 767 } 768 769 @Override tryAdvance(T_CONS action)770 public boolean tryAdvance(T_CONS action) { 771 Objects.requireNonNull(action); 772 773 if (sliceOrigin >= fence) 774 return false; 775 776 while (sliceOrigin > index) { 777 s.tryAdvance(emptyConsumer()); 778 index++; 779 } 780 781 if (index >= fence) 782 return false; 783 784 index++; 785 return s.tryAdvance(action); 786 } 787 788 @Override forEachRemaining(T_CONS action)789 public void forEachRemaining(T_CONS action) { 790 Objects.requireNonNull(action); 791 792 if (sliceOrigin >= fence) 793 return; 794 795 if (index >= fence) 796 return; 797 798 if (index >= sliceOrigin && (index + s.estimateSize()) <= sliceFence) { 799 // The spliterator is contained within the slice 800 s.forEachRemaining(action); 801 index = fence; 802 } else { 803 // The spliterator intersects with the slice 804 while (sliceOrigin > index) { 805 s.tryAdvance(emptyConsumer()); 806 index++; 807 } 808 // Traverse elements up to the fence 809 for (;index < fence; index++) { 810 s.tryAdvance(action); 811 } 812 } 813 } 814 emptyConsumer()815 protected abstract T_CONS emptyConsumer(); 816 } 817 818 static final class OfInt extends OfPrimitive<Integer, Spliterator.OfInt, IntConsumer> 819 implements Spliterator.OfInt { OfInt(Spliterator.OfInt s, long sliceOrigin, long sliceFence)820 OfInt(Spliterator.OfInt s, long sliceOrigin, long sliceFence) { 821 super(s, sliceOrigin, sliceFence); 822 } 823 OfInt(Spliterator.OfInt s, long sliceOrigin, long sliceFence, long origin, long fence)824 OfInt(Spliterator.OfInt s, 825 long sliceOrigin, long sliceFence, long origin, long fence) { 826 super(s, sliceOrigin, sliceFence, origin, fence); 827 } 828 829 @Override makeSpliterator(Spliterator.OfInt s, long sliceOrigin, long sliceFence, long origin, long fence)830 protected Spliterator.OfInt makeSpliterator(Spliterator.OfInt s, 831 long sliceOrigin, long sliceFence, 832 long origin, long fence) { 833 return new SliceSpliterator.OfInt(s, sliceOrigin, sliceFence, origin, fence); 834 } 835 836 @Override emptyConsumer()837 protected IntConsumer emptyConsumer() { 838 return e -> {}; 839 } 840 } 841 842 static final class OfLong extends OfPrimitive<Long, Spliterator.OfLong, LongConsumer> 843 implements Spliterator.OfLong { OfLong(Spliterator.OfLong s, long sliceOrigin, long sliceFence)844 OfLong(Spliterator.OfLong s, long sliceOrigin, long sliceFence) { 845 super(s, sliceOrigin, sliceFence); 846 } 847 OfLong(Spliterator.OfLong s, long sliceOrigin, long sliceFence, long origin, long fence)848 OfLong(Spliterator.OfLong s, 849 long sliceOrigin, long sliceFence, long origin, long fence) { 850 super(s, sliceOrigin, sliceFence, origin, fence); 851 } 852 853 @Override makeSpliterator(Spliterator.OfLong s, long sliceOrigin, long sliceFence, long origin, long fence)854 protected Spliterator.OfLong makeSpliterator(Spliterator.OfLong s, 855 long sliceOrigin, long sliceFence, 856 long origin, long fence) { 857 return new SliceSpliterator.OfLong(s, sliceOrigin, sliceFence, origin, fence); 858 } 859 860 @Override emptyConsumer()861 protected LongConsumer emptyConsumer() { 862 return e -> {}; 863 } 864 } 865 866 static final class OfDouble extends OfPrimitive<Double, Spliterator.OfDouble, DoubleConsumer> 867 implements Spliterator.OfDouble { OfDouble(Spliterator.OfDouble s, long sliceOrigin, long sliceFence)868 OfDouble(Spliterator.OfDouble s, long sliceOrigin, long sliceFence) { 869 super(s, sliceOrigin, sliceFence); 870 } 871 OfDouble(Spliterator.OfDouble s, long sliceOrigin, long sliceFence, long origin, long fence)872 OfDouble(Spliterator.OfDouble s, 873 long sliceOrigin, long sliceFence, long origin, long fence) { 874 super(s, sliceOrigin, sliceFence, origin, fence); 875 } 876 877 @Override makeSpliterator(Spliterator.OfDouble s, long sliceOrigin, long sliceFence, long origin, long fence)878 protected Spliterator.OfDouble makeSpliterator(Spliterator.OfDouble s, 879 long sliceOrigin, long sliceFence, 880 long origin, long fence) { 881 return new SliceSpliterator.OfDouble(s, sliceOrigin, sliceFence, origin, fence); 882 } 883 884 @Override emptyConsumer()885 protected DoubleConsumer emptyConsumer() { 886 return e -> {}; 887 } 888 } 889 } 890 891 /** 892 * A slice Spliterator that does not preserve order, if any, of a source 893 * Spliterator. 894 * 895 * Note: The source spliterator may report {@code ORDERED} since that 896 * spliterator be the result of a previous pipeline stage that was 897 * collected to a {@code Node}. It is the order of the pipeline stage 898 * that governs whether this slice spliterator is to be used or not. 899 */ 900 abstract static class UnorderedSliceSpliterator<T, T_SPLITR extends Spliterator<T>> { 901 static final int CHUNK_SIZE = 1 << 7; 902 903 // The spliterator to slice 904 protected final T_SPLITR s; 905 protected final boolean unlimited; 906 protected final int chunkSize; 907 private final long skipThreshold; 908 private final AtomicLong permits; 909 UnorderedSliceSpliterator(T_SPLITR s, long skip, long limit)910 UnorderedSliceSpliterator(T_SPLITR s, long skip, long limit) { 911 this.s = s; 912 this.unlimited = limit < 0; 913 this.skipThreshold = limit >= 0 ? limit : 0; 914 this.chunkSize = limit >= 0 ? (int)Math.min(CHUNK_SIZE, 915 ((skip + limit) / AbstractTask.getLeafTarget()) + 1) : CHUNK_SIZE; 916 this.permits = new AtomicLong(limit >= 0 ? skip + limit : skip); 917 } 918 UnorderedSliceSpliterator(T_SPLITR s, UnorderedSliceSpliterator<T, T_SPLITR> parent)919 UnorderedSliceSpliterator(T_SPLITR s, 920 UnorderedSliceSpliterator<T, T_SPLITR> parent) { 921 this.s = s; 922 this.unlimited = parent.unlimited; 923 this.permits = parent.permits; 924 this.skipThreshold = parent.skipThreshold; 925 this.chunkSize = parent.chunkSize; 926 } 927 928 /** 929 * Acquire permission to skip or process elements. The caller must 930 * first acquire the elements, then consult this method for guidance 931 * as to what to do with the data. 932 * 933 * <p>We use an {@code AtomicLong} to atomically maintain a counter, 934 * which is initialized as skip+limit if we are limiting, or skip only 935 * if we are not limiting. The user should consult the method 936 * {@code checkPermits()} before acquiring data elements. 937 * 938 * @param numElements the number of elements the caller has in hand 939 * @return the number of elements that should be processed; any 940 * remaining elements should be discarded. 941 */ acquirePermits(long numElements)942 protected final long acquirePermits(long numElements) { 943 long remainingPermits; 944 long grabbing; 945 // permits never increase, and don't decrease below zero 946 assert numElements > 0; 947 do { 948 remainingPermits = permits.get(); 949 if (remainingPermits == 0) 950 return unlimited ? numElements : 0; 951 grabbing = Math.min(remainingPermits, numElements); 952 } while (grabbing > 0 && 953 !permits.compareAndSet(remainingPermits, remainingPermits - grabbing)); 954 955 if (unlimited) 956 return Math.max(numElements - grabbing, 0); 957 else if (remainingPermits > skipThreshold) 958 return Math.max(grabbing - (remainingPermits - skipThreshold), 0); 959 else 960 return grabbing; 961 } 962 963 enum PermitStatus { NO_MORE, MAYBE_MORE, UNLIMITED } 964 965 /** Call to check if permits might be available before acquiring data */ permitStatus()966 protected final PermitStatus permitStatus() { 967 if (permits.get() > 0) 968 return PermitStatus.MAYBE_MORE; 969 else 970 return unlimited ? PermitStatus.UNLIMITED : PermitStatus.NO_MORE; 971 } 972 trySplit()973 public final T_SPLITR trySplit() { 974 // Stop splitting when there are no more limit permits 975 if (permits.get() == 0) 976 return null; 977 @SuppressWarnings("unchecked") 978 T_SPLITR split = (T_SPLITR) s.trySplit(); 979 return split == null ? null : makeSpliterator(split); 980 } 981 makeSpliterator(T_SPLITR s)982 protected abstract T_SPLITR makeSpliterator(T_SPLITR s); 983 estimateSize()984 public final long estimateSize() { 985 return s.estimateSize(); 986 } 987 characteristics()988 public final int characteristics() { 989 return s.characteristics() & 990 ~(Spliterator.SIZED | Spliterator.SUBSIZED | Spliterator.ORDERED); 991 } 992 993 static final class OfRef<T> extends UnorderedSliceSpliterator<T, Spliterator<T>> 994 implements Spliterator<T>, Consumer<T> { 995 T tmpSlot; 996 OfRef(Spliterator<T> s, long skip, long limit)997 OfRef(Spliterator<T> s, long skip, long limit) { 998 super(s, skip, limit); 999 } 1000 OfRef(Spliterator<T> s, OfRef<T> parent)1001 OfRef(Spliterator<T> s, OfRef<T> parent) { 1002 super(s, parent); 1003 } 1004 1005 @Override accept(T t)1006 public final void accept(T t) { 1007 tmpSlot = t; 1008 } 1009 1010 @Override tryAdvance(Consumer<? super T> action)1011 public boolean tryAdvance(Consumer<? super T> action) { 1012 Objects.requireNonNull(action); 1013 1014 while (permitStatus() != PermitStatus.NO_MORE) { 1015 if (!s.tryAdvance(this)) 1016 return false; 1017 else if (acquirePermits(1) == 1) { 1018 action.accept(tmpSlot); 1019 tmpSlot = null; 1020 return true; 1021 } 1022 } 1023 return false; 1024 } 1025 1026 @Override forEachRemaining(Consumer<? super T> action)1027 public void forEachRemaining(Consumer<? super T> action) { 1028 Objects.requireNonNull(action); 1029 1030 ArrayBuffer.OfRef<T> sb = null; 1031 PermitStatus permitStatus; 1032 while ((permitStatus = permitStatus()) != PermitStatus.NO_MORE) { 1033 if (permitStatus == PermitStatus.MAYBE_MORE) { 1034 // Optimistically traverse elements up to a threshold of chunkSize 1035 if (sb == null) 1036 sb = new ArrayBuffer.OfRef<>(chunkSize); 1037 else 1038 sb.reset(); 1039 long permitsRequested = 0; 1040 do { } while (s.tryAdvance(sb) && ++permitsRequested < chunkSize); 1041 if (permitsRequested == 0) 1042 return; 1043 sb.forEach(action, acquirePermits(permitsRequested)); 1044 } 1045 else { 1046 // Must be UNLIMITED; let 'er rip 1047 s.forEachRemaining(action); 1048 return; 1049 } 1050 } 1051 } 1052 1053 @Override makeSpliterator(Spliterator<T> s)1054 protected Spliterator<T> makeSpliterator(Spliterator<T> s) { 1055 return new UnorderedSliceSpliterator.OfRef<>(s, this); 1056 } 1057 } 1058 1059 /** 1060 * Concrete sub-types must also be an instance of type {@code T_CONS}. 1061 * 1062 * @param <T_BUFF> the type of the spined buffer. Must also be a type of 1063 * {@code T_CONS}. 1064 */ 1065 abstract static class OfPrimitive< 1066 T, 1067 T_CONS, 1068 T_BUFF extends ArrayBuffer.OfPrimitive<T_CONS>, 1069 T_SPLITR extends Spliterator.OfPrimitive<T, T_CONS, T_SPLITR>> 1070 extends UnorderedSliceSpliterator<T, T_SPLITR> 1071 implements Spliterator.OfPrimitive<T, T_CONS, T_SPLITR> { OfPrimitive(T_SPLITR s, long skip, long limit)1072 OfPrimitive(T_SPLITR s, long skip, long limit) { 1073 super(s, skip, limit); 1074 } 1075 OfPrimitive(T_SPLITR s, UnorderedSliceSpliterator.OfPrimitive<T, T_CONS, T_BUFF, T_SPLITR> parent)1076 OfPrimitive(T_SPLITR s, UnorderedSliceSpliterator.OfPrimitive<T, T_CONS, T_BUFF, T_SPLITR> parent) { 1077 super(s, parent); 1078 } 1079 1080 @Override tryAdvance(T_CONS action)1081 public boolean tryAdvance(T_CONS action) { 1082 Objects.requireNonNull(action); 1083 @SuppressWarnings("unchecked") 1084 T_CONS consumer = (T_CONS) this; 1085 1086 while (permitStatus() != PermitStatus.NO_MORE) { 1087 if (!s.tryAdvance(consumer)) 1088 return false; 1089 else if (acquirePermits(1) == 1) { 1090 acceptConsumed(action); 1091 return true; 1092 } 1093 } 1094 return false; 1095 } 1096 acceptConsumed(T_CONS action)1097 protected abstract void acceptConsumed(T_CONS action); 1098 1099 @Override forEachRemaining(T_CONS action)1100 public void forEachRemaining(T_CONS action) { 1101 Objects.requireNonNull(action); 1102 1103 T_BUFF sb = null; 1104 PermitStatus permitStatus; 1105 while ((permitStatus = permitStatus()) != PermitStatus.NO_MORE) { 1106 if (permitStatus == PermitStatus.MAYBE_MORE) { 1107 // Optimistically traverse elements up to a threshold of chunkSize 1108 if (sb == null) 1109 sb = bufferCreate(chunkSize); 1110 else 1111 sb.reset(); 1112 @SuppressWarnings("unchecked") 1113 T_CONS sbc = (T_CONS) sb; 1114 long permitsRequested = 0; 1115 do { } while (s.tryAdvance(sbc) && ++permitsRequested < chunkSize); 1116 if (permitsRequested == 0) 1117 return; 1118 sb.forEach(action, acquirePermits(permitsRequested)); 1119 } 1120 else { 1121 // Must be UNLIMITED; let 'er rip 1122 s.forEachRemaining(action); 1123 return; 1124 } 1125 } 1126 } 1127 bufferCreate(int initialCapacity)1128 protected abstract T_BUFF bufferCreate(int initialCapacity); 1129 } 1130 1131 static final class OfInt 1132 extends OfPrimitive<Integer, IntConsumer, ArrayBuffer.OfInt, Spliterator.OfInt> 1133 implements Spliterator.OfInt, IntConsumer { 1134 1135 int tmpValue; 1136 OfInt(Spliterator.OfInt s, long skip, long limit)1137 OfInt(Spliterator.OfInt s, long skip, long limit) { 1138 super(s, skip, limit); 1139 } 1140 OfInt(Spliterator.OfInt s, UnorderedSliceSpliterator.OfInt parent)1141 OfInt(Spliterator.OfInt s, UnorderedSliceSpliterator.OfInt parent) { 1142 super(s, parent); 1143 } 1144 1145 @Override accept(int value)1146 public void accept(int value) { 1147 tmpValue = value; 1148 } 1149 1150 @Override acceptConsumed(IntConsumer action)1151 protected void acceptConsumed(IntConsumer action) { 1152 action.accept(tmpValue); 1153 } 1154 1155 @Override bufferCreate(int initialCapacity)1156 protected ArrayBuffer.OfInt bufferCreate(int initialCapacity) { 1157 return new ArrayBuffer.OfInt(initialCapacity); 1158 } 1159 1160 @Override makeSpliterator(Spliterator.OfInt s)1161 protected Spliterator.OfInt makeSpliterator(Spliterator.OfInt s) { 1162 return new UnorderedSliceSpliterator.OfInt(s, this); 1163 } 1164 } 1165 1166 static final class OfLong 1167 extends OfPrimitive<Long, LongConsumer, ArrayBuffer.OfLong, Spliterator.OfLong> 1168 implements Spliterator.OfLong, LongConsumer { 1169 1170 long tmpValue; 1171 OfLong(Spliterator.OfLong s, long skip, long limit)1172 OfLong(Spliterator.OfLong s, long skip, long limit) { 1173 super(s, skip, limit); 1174 } 1175 OfLong(Spliterator.OfLong s, UnorderedSliceSpliterator.OfLong parent)1176 OfLong(Spliterator.OfLong s, UnorderedSliceSpliterator.OfLong parent) { 1177 super(s, parent); 1178 } 1179 1180 @Override accept(long value)1181 public void accept(long value) { 1182 tmpValue = value; 1183 } 1184 1185 @Override acceptConsumed(LongConsumer action)1186 protected void acceptConsumed(LongConsumer action) { 1187 action.accept(tmpValue); 1188 } 1189 1190 @Override bufferCreate(int initialCapacity)1191 protected ArrayBuffer.OfLong bufferCreate(int initialCapacity) { 1192 return new ArrayBuffer.OfLong(initialCapacity); 1193 } 1194 1195 @Override makeSpliterator(Spliterator.OfLong s)1196 protected Spliterator.OfLong makeSpliterator(Spliterator.OfLong s) { 1197 return new UnorderedSliceSpliterator.OfLong(s, this); 1198 } 1199 } 1200 1201 static final class OfDouble 1202 extends OfPrimitive<Double, DoubleConsumer, ArrayBuffer.OfDouble, Spliterator.OfDouble> 1203 implements Spliterator.OfDouble, DoubleConsumer { 1204 1205 double tmpValue; 1206 OfDouble(Spliterator.OfDouble s, long skip, long limit)1207 OfDouble(Spliterator.OfDouble s, long skip, long limit) { 1208 super(s, skip, limit); 1209 } 1210 OfDouble(Spliterator.OfDouble s, UnorderedSliceSpliterator.OfDouble parent)1211 OfDouble(Spliterator.OfDouble s, UnorderedSliceSpliterator.OfDouble parent) { 1212 super(s, parent); 1213 } 1214 1215 @Override accept(double value)1216 public void accept(double value) { 1217 tmpValue = value; 1218 } 1219 1220 @Override acceptConsumed(DoubleConsumer action)1221 protected void acceptConsumed(DoubleConsumer action) { 1222 action.accept(tmpValue); 1223 } 1224 1225 @Override bufferCreate(int initialCapacity)1226 protected ArrayBuffer.OfDouble bufferCreate(int initialCapacity) { 1227 return new ArrayBuffer.OfDouble(initialCapacity); 1228 } 1229 1230 @Override makeSpliterator(Spliterator.OfDouble s)1231 protected Spliterator.OfDouble makeSpliterator(Spliterator.OfDouble s) { 1232 return new UnorderedSliceSpliterator.OfDouble(s, this); 1233 } 1234 } 1235 } 1236 1237 /** 1238 * A wrapping spliterator that only reports distinct elements of the 1239 * underlying spliterator. Does not preserve size and encounter order. 1240 */ 1241 static final class DistinctSpliterator<T> implements Spliterator<T>, Consumer<T> { 1242 1243 // The value to represent null in the ConcurrentHashMap 1244 private static final Object NULL_VALUE = new Object(); 1245 1246 // The underlying spliterator 1247 private final Spliterator<T> s; 1248 1249 // ConcurrentHashMap holding distinct elements as keys 1250 private final ConcurrentHashMap<T, Boolean> seen; 1251 1252 // Temporary element, only used with tryAdvance 1253 private T tmpSlot; 1254 DistinctSpliterator(Spliterator<T> s)1255 DistinctSpliterator(Spliterator<T> s) { 1256 this(s, new ConcurrentHashMap<>()); 1257 } 1258 DistinctSpliterator(Spliterator<T> s, ConcurrentHashMap<T, Boolean> seen)1259 private DistinctSpliterator(Spliterator<T> s, ConcurrentHashMap<T, Boolean> seen) { 1260 this.s = s; 1261 this.seen = seen; 1262 } 1263 1264 @Override accept(T t)1265 public void accept(T t) { 1266 this.tmpSlot = t; 1267 } 1268 1269 @SuppressWarnings("unchecked") mapNull(T t)1270 private T mapNull(T t) { 1271 return t != null ? t : (T) NULL_VALUE; 1272 } 1273 1274 @Override tryAdvance(Consumer<? super T> action)1275 public boolean tryAdvance(Consumer<? super T> action) { 1276 while (s.tryAdvance(this)) { 1277 if (seen.putIfAbsent(mapNull(tmpSlot), Boolean.TRUE) == null) { 1278 action.accept(tmpSlot); 1279 tmpSlot = null; 1280 return true; 1281 } 1282 } 1283 return false; 1284 } 1285 1286 @Override forEachRemaining(Consumer<? super T> action)1287 public void forEachRemaining(Consumer<? super T> action) { 1288 s.forEachRemaining(t -> { 1289 if (seen.putIfAbsent(mapNull(t), Boolean.TRUE) == null) { 1290 action.accept(t); 1291 } 1292 }); 1293 } 1294 1295 @Override trySplit()1296 public Spliterator<T> trySplit() { 1297 Spliterator<T> split = s.trySplit(); 1298 return (split != null) ? new DistinctSpliterator<>(split, seen) : null; 1299 } 1300 1301 @Override estimateSize()1302 public long estimateSize() { 1303 return s.estimateSize(); 1304 } 1305 1306 @Override characteristics()1307 public int characteristics() { 1308 return (s.characteristics() & ~(Spliterator.SIZED | Spliterator.SUBSIZED | 1309 Spliterator.SORTED | Spliterator.ORDERED)) 1310 | Spliterator.DISTINCT; 1311 } 1312 1313 @Override getComparator()1314 public Comparator<? super T> getComparator() { 1315 return s.getComparator(); 1316 } 1317 } 1318 1319 /** 1320 * A Spliterator that infinitely supplies elements in no particular order. 1321 * 1322 * <p>Splitting divides the estimated size in two and stops when the 1323 * estimate size is 0. 1324 * 1325 * <p>The {@code forEachRemaining} method if invoked will never terminate. 1326 * The {@code tryAdvance} method always returns true. 1327 * 1328 */ 1329 abstract static class InfiniteSupplyingSpliterator<T> implements Spliterator<T> { 1330 long estimate; 1331 InfiniteSupplyingSpliterator(long estimate)1332 protected InfiniteSupplyingSpliterator(long estimate) { 1333 this.estimate = estimate; 1334 } 1335 1336 @Override estimateSize()1337 public long estimateSize() { 1338 return estimate; 1339 } 1340 1341 @Override characteristics()1342 public int characteristics() { 1343 return IMMUTABLE; 1344 } 1345 1346 static final class OfRef<T> extends InfiniteSupplyingSpliterator<T> { 1347 final Supplier<? extends T> s; 1348 OfRef(long size, Supplier<? extends T> s)1349 OfRef(long size, Supplier<? extends T> s) { 1350 super(size); 1351 this.s = s; 1352 } 1353 1354 @Override tryAdvance(Consumer<? super T> action)1355 public boolean tryAdvance(Consumer<? super T> action) { 1356 Objects.requireNonNull(action); 1357 1358 action.accept(s.get()); 1359 return true; 1360 } 1361 1362 @Override trySplit()1363 public Spliterator<T> trySplit() { 1364 if (estimate == 0) 1365 return null; 1366 return new InfiniteSupplyingSpliterator.OfRef<>(estimate >>>= 1, s); 1367 } 1368 } 1369 1370 static final class OfInt extends InfiniteSupplyingSpliterator<Integer> 1371 implements Spliterator.OfInt { 1372 final IntSupplier s; 1373 OfInt(long size, IntSupplier s)1374 OfInt(long size, IntSupplier s) { 1375 super(size); 1376 this.s = s; 1377 } 1378 1379 @Override tryAdvance(IntConsumer action)1380 public boolean tryAdvance(IntConsumer action) { 1381 Objects.requireNonNull(action); 1382 1383 action.accept(s.getAsInt()); 1384 return true; 1385 } 1386 1387 @Override trySplit()1388 public Spliterator.OfInt trySplit() { 1389 if (estimate == 0) 1390 return null; 1391 return new InfiniteSupplyingSpliterator.OfInt(estimate = estimate >>> 1, s); 1392 } 1393 } 1394 1395 static final class OfLong extends InfiniteSupplyingSpliterator<Long> 1396 implements Spliterator.OfLong { 1397 final LongSupplier s; 1398 OfLong(long size, LongSupplier s)1399 OfLong(long size, LongSupplier s) { 1400 super(size); 1401 this.s = s; 1402 } 1403 1404 @Override tryAdvance(LongConsumer action)1405 public boolean tryAdvance(LongConsumer action) { 1406 Objects.requireNonNull(action); 1407 1408 action.accept(s.getAsLong()); 1409 return true; 1410 } 1411 1412 @Override trySplit()1413 public Spliterator.OfLong trySplit() { 1414 if (estimate == 0) 1415 return null; 1416 return new InfiniteSupplyingSpliterator.OfLong(estimate = estimate >>> 1, s); 1417 } 1418 } 1419 1420 static final class OfDouble extends InfiniteSupplyingSpliterator<Double> 1421 implements Spliterator.OfDouble { 1422 final DoubleSupplier s; 1423 OfDouble(long size, DoubleSupplier s)1424 OfDouble(long size, DoubleSupplier s) { 1425 super(size); 1426 this.s = s; 1427 } 1428 1429 @Override tryAdvance(DoubleConsumer action)1430 public boolean tryAdvance(DoubleConsumer action) { 1431 Objects.requireNonNull(action); 1432 1433 action.accept(s.getAsDouble()); 1434 return true; 1435 } 1436 1437 @Override trySplit()1438 public Spliterator.OfDouble trySplit() { 1439 if (estimate == 0) 1440 return null; 1441 return new InfiniteSupplyingSpliterator.OfDouble(estimate = estimate >>> 1, s); 1442 } 1443 } 1444 } 1445 1446 // @@@ Consolidate with Node.Builder 1447 abstract static class ArrayBuffer { 1448 int index; 1449 reset()1450 void reset() { 1451 index = 0; 1452 } 1453 1454 static final class OfRef<T> extends ArrayBuffer implements Consumer<T> { 1455 final Object[] array; 1456 OfRef(int size)1457 OfRef(int size) { 1458 this.array = new Object[size]; 1459 } 1460 1461 @Override accept(T t)1462 public void accept(T t) { 1463 array[index++] = t; 1464 } 1465 forEach(Consumer<? super T> action, long fence)1466 public void forEach(Consumer<? super T> action, long fence) { 1467 for (int i = 0; i < fence; i++) { 1468 @SuppressWarnings("unchecked") 1469 T t = (T) array[i]; 1470 action.accept(t); 1471 } 1472 } 1473 } 1474 1475 abstract static class OfPrimitive<T_CONS> extends ArrayBuffer { 1476 int index; 1477 1478 @Override reset()1479 void reset() { 1480 index = 0; 1481 } 1482 forEach(T_CONS action, long fence)1483 abstract void forEach(T_CONS action, long fence); 1484 } 1485 1486 static final class OfInt extends OfPrimitive<IntConsumer> 1487 implements IntConsumer { 1488 final int[] array; 1489 OfInt(int size)1490 OfInt(int size) { 1491 this.array = new int[size]; 1492 } 1493 1494 @Override accept(int t)1495 public void accept(int t) { 1496 array[index++] = t; 1497 } 1498 1499 @Override forEach(IntConsumer action, long fence)1500 public void forEach(IntConsumer action, long fence) { 1501 for (int i = 0; i < fence; i++) { 1502 action.accept(array[i]); 1503 } 1504 } 1505 } 1506 1507 static final class OfLong extends OfPrimitive<LongConsumer> 1508 implements LongConsumer { 1509 final long[] array; 1510 OfLong(int size)1511 OfLong(int size) { 1512 this.array = new long[size]; 1513 } 1514 1515 @Override accept(long t)1516 public void accept(long t) { 1517 array[index++] = t; 1518 } 1519 1520 @Override forEach(LongConsumer action, long fence)1521 public void forEach(LongConsumer action, long fence) { 1522 for (int i = 0; i < fence; i++) { 1523 action.accept(array[i]); 1524 } 1525 } 1526 } 1527 1528 static final class OfDouble extends OfPrimitive<DoubleConsumer> 1529 implements DoubleConsumer { 1530 final double[] array; 1531 OfDouble(int size)1532 OfDouble(int size) { 1533 this.array = new double[size]; 1534 } 1535 1536 @Override accept(double t)1537 public void accept(double t) { 1538 array[index++] = t; 1539 } 1540 1541 @Override forEach(DoubleConsumer action, long fence)1542 void forEach(DoubleConsumer action, long fence) { 1543 for (int i = 0; i < fence; i++) { 1544 action.accept(array[i]); 1545 } 1546 } 1547 } 1548 } 1549 } 1550 1551