001/*
002 * Copyright (C) 2011 The Guava Authors
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
005 * in compliance with the License. You may obtain a copy of the License at
006 *
007 * http://www.apache.org/licenses/LICENSE-2.0
008 *
009 * Unless required by applicable law or agreed to in writing, software distributed under the
010 * License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
011 * express or implied. See the License for the specific language governing permissions and
012 * limitations under the License.
013 */
014
015package com.google.common.collect;
016
017import static com.google.common.base.Preconditions.checkArgument;
018import static com.google.common.base.Preconditions.checkNotNull;
019
020import com.google.common.annotations.GwtIncompatible;
021import com.google.common.annotations.J2ktIncompatible;
022import com.google.common.annotations.VisibleForTesting;
023import com.google.common.math.IntMath;
024import com.google.errorprone.annotations.CanIgnoreReturnValue;
025import com.google.errorprone.annotations.DoNotCall;
026import com.google.errorprone.annotations.concurrent.LazyInit;
027import java.io.InvalidObjectException;
028import java.io.ObjectInputStream;
029import java.io.Serializable;
030import java.util.Arrays;
031import java.util.Collection;
032import java.util.Collections;
033import java.util.Comparator;
034import java.util.Iterator;
035import java.util.List;
036import java.util.function.Function;
037import java.util.function.ToIntFunction;
038import java.util.stream.Collector;
039import javax.annotation.CheckForNull;
040import org.checkerframework.checker.nullness.qual.Nullable;
041
042/**
043 * A {@link SortedMultiset} whose contents will never change, with many other important properties
044 * detailed at {@link ImmutableCollection}.
045 *
046 * <p><b>Warning:</b> as with any sorted collection, you are strongly advised not to use a {@link
047 * Comparator} or {@link Comparable} type whose comparison behavior is <i>inconsistent with
048 * equals</i>. That is, {@code a.compareTo(b)} or {@code comparator.compare(a, b)} should equal zero
049 * <i>if and only if</i> {@code a.equals(b)}. If this advice is not followed, the resulting
050 * collection will not correctly obey its specification.
051 *
052 * <p>See the Guava User Guide article on <a href=
053 * "https://github.com/google/guava/wiki/ImmutableCollectionsExplained">immutable collections</a>.
054 *
055 * @author Louis Wasserman
056 * @since 12.0
057 */
058@GwtIncompatible // hasn't been tested yet
059@ElementTypesAreNonnullByDefault
060public abstract class ImmutableSortedMultiset<E> extends ImmutableMultiset<E>
061    implements SortedMultiset<E> {
062  // TODO(lowasser): GWT compatibility
063
064  /**
065   * Returns a {@code Collector} that accumulates the input elements into a new {@code
066   * ImmutableMultiset}. Elements are sorted by the specified comparator.
067   *
068   * <p><b>Warning:</b> {@code comparator} should be <i>consistent with {@code equals}</i> as
069   * explained in the {@link Comparator} documentation.
070   */
071  @SuppressWarnings({"AndroidJdkLibsChecker", "Java7ApiChecker"})
072  @IgnoreJRERequirement // Users will use this only if they're already using streams.
073  static <E> Collector<E, ?, ImmutableSortedMultiset<E>> toImmutableSortedMultiset(
074      Comparator<? super E> comparator) {
075    return toImmutableSortedMultiset(comparator, Function.identity(), e -> 1);
076  }
077
078  /**
079   * Returns a {@code Collector} that accumulates elements into an {@code ImmutableSortedMultiset}
080   * whose elements are the result of applying {@code elementFunction} to the inputs, with counts
081   * equal to the result of applying {@code countFunction} to the inputs.
082   *
083   * <p>If the mapped elements contain duplicates (according to {@code comparator}), the first
084   * occurrence in encounter order appears in the resulting multiset, with count equal to the sum of
085   * the outputs of {@code countFunction.applyAsInt(t)} for each {@code t} mapped to that element.
086   */
087  @SuppressWarnings({"AndroidJdkLibsChecker", "Java7ApiChecker"})
088  @IgnoreJRERequirement // Users will use this only if they're already using streams.
089  static <T extends @Nullable Object, E>
090      Collector<T, ?, ImmutableSortedMultiset<E>> toImmutableSortedMultiset(
091          Comparator<? super E> comparator,
092          Function<? super T, ? extends E> elementFunction,
093          ToIntFunction<? super T> countFunction) {
094    checkNotNull(comparator);
095    checkNotNull(elementFunction);
096    checkNotNull(countFunction);
097    return Collector.of(
098        () -> TreeMultiset.create(comparator),
099        (multiset, t) -> mapAndAdd(t, multiset, elementFunction, countFunction),
100        (multiset1, multiset2) -> {
101          multiset1.addAll(multiset2);
102          return multiset1;
103        },
104        (Multiset<E> multiset) -> copyOfSortedEntries(comparator, multiset.entrySet()));
105  }
106
107  @SuppressWarnings({"AndroidJdkLibsChecker", "Java7ApiChecker"})
108  @IgnoreJRERequirement // helper for toImmutableSortedMultiset
109  /*
110   * If we make these calls inline inside toImmutableSortedMultiset, we get an Animal Sniffer error,
111   * despite the @IgnoreJRERequirement annotation there. My assumption is that, because javac
112   * generates a synthetic method for the body of the lambda, the actual method calls that Animal
113   * Sniffer is flagging don't appear inside toImmutableSortedMultiset but rather inside that
114   * synthetic method. By moving those calls to a named method, we're able to apply
115   * @IgnoreJRERequirement somewhere that it will help.
116   */
117  private static <T extends @Nullable Object, E> void mapAndAdd(
118      T t,
119      Multiset<E> multiset,
120      Function<? super T, ? extends E> elementFunction,
121      ToIntFunction<? super T> countFunction) {
122    multiset.add(checkNotNull(elementFunction.apply(t)), countFunction.applyAsInt(t));
123  }
124
125  /**
126   * Returns the empty immutable sorted multiset.
127   *
128   * <p><b>Performance note:</b> the instance returned is a singleton.
129   */
130  @SuppressWarnings("unchecked")
131  public static <E> ImmutableSortedMultiset<E> of() {
132    return (ImmutableSortedMultiset) RegularImmutableSortedMultiset.NATURAL_EMPTY_MULTISET;
133  }
134
135  /** Returns an immutable sorted multiset containing a single element. */
136  public static <E extends Comparable<? super E>> ImmutableSortedMultiset<E> of(E element) {
137    RegularImmutableSortedSet<E> elementSet =
138        (RegularImmutableSortedSet<E>) ImmutableSortedSet.of(element);
139    long[] cumulativeCounts = {0, 1};
140    return new RegularImmutableSortedMultiset<E>(elementSet, cumulativeCounts, 0, 1);
141  }
142
143  /**
144   * Returns an immutable sorted multiset containing the given elements sorted by their natural
145   * ordering.
146   *
147   * @throws NullPointerException if any element is null
148   */
149  public static <E extends Comparable<? super E>> ImmutableSortedMultiset<E> of(E e1, E e2) {
150    return copyOf(Ordering.natural(), Arrays.asList(e1, e2));
151  }
152
153  /**
154   * Returns an immutable sorted multiset containing the given elements sorted by their natural
155   * ordering.
156   *
157   * @throws NullPointerException if any element is null
158   */
159  public static <E extends Comparable<? super E>> ImmutableSortedMultiset<E> of(E e1, E e2, E e3) {
160    return copyOf(Ordering.natural(), Arrays.asList(e1, e2, e3));
161  }
162
163  /**
164   * Returns an immutable sorted multiset containing the given elements sorted by their natural
165   * ordering.
166   *
167   * @throws NullPointerException if any element is null
168   */
169  public static <E extends Comparable<? super E>> ImmutableSortedMultiset<E> of(
170      E e1, E e2, E e3, E e4) {
171    return copyOf(Ordering.natural(), Arrays.asList(e1, e2, e3, e4));
172  }
173
174  /**
175   * Returns an immutable sorted multiset containing the given elements sorted by their natural
176   * ordering.
177   *
178   * @throws NullPointerException if any element is null
179   */
180  public static <E extends Comparable<? super E>> ImmutableSortedMultiset<E> of(
181      E e1, E e2, E e3, E e4, E e5) {
182    return copyOf(Ordering.natural(), Arrays.asList(e1, e2, e3, e4, e5));
183  }
184
185  /**
186   * Returns an immutable sorted multiset containing the given elements sorted by their natural
187   * ordering.
188   *
189   * @throws NullPointerException if any element is null
190   */
191  public static <E extends Comparable<? super E>> ImmutableSortedMultiset<E> of(
192      E e1, E e2, E e3, E e4, E e5, E e6, E... remaining) {
193    int size = remaining.length + 6;
194    List<E> all = Lists.newArrayListWithCapacity(size);
195    Collections.addAll(all, e1, e2, e3, e4, e5, e6);
196    Collections.addAll(all, remaining);
197    return copyOf(Ordering.natural(), all);
198  }
199
200  /**
201   * Returns an immutable sorted multiset containing the given elements sorted by their natural
202   * ordering.
203   *
204   * @throws NullPointerException if any of {@code elements} is null
205   */
206  public static <E extends Comparable<? super E>> ImmutableSortedMultiset<E> copyOf(E[] elements) {
207    return copyOf(Ordering.natural(), Arrays.asList(elements));
208  }
209
210  /**
211   * Returns an immutable sorted multiset containing the given elements sorted by their natural
212   * ordering. To create a copy of a {@code SortedMultiset} that preserves the comparator, call
213   * {@link #copyOfSorted} instead. This method iterates over {@code elements} at most once.
214   *
215   * <p>Note that if {@code s} is a {@code Multiset<String>}, then {@code
216   * ImmutableSortedMultiset.copyOf(s)} returns an {@code ImmutableSortedMultiset<String>}
217   * containing each of the strings in {@code s}, while {@code ImmutableSortedMultiset.of(s)}
218   * returns an {@code ImmutableSortedMultiset<Multiset<String>>} containing one element (the given
219   * multiset itself).
220   *
221   * <p>Despite the method name, this method attempts to avoid actually copying the data when it is
222   * safe to do so. The exact circumstances under which a copy will or will not be performed are
223   * undocumented and subject to change.
224   *
225   * <p>This method is not type-safe, as it may be called on elements that are not mutually
226   * comparable.
227   *
228   * @throws ClassCastException if the elements are not mutually comparable
229   * @throws NullPointerException if any of {@code elements} is null
230   */
231  public static <E> ImmutableSortedMultiset<E> copyOf(Iterable<? extends E> elements) {
232    // Hack around E not being a subtype of Comparable.
233    // Unsafe, see ImmutableSortedMultisetFauxverideShim.
234    @SuppressWarnings("unchecked")
235    Ordering<E> naturalOrder = (Ordering<E>) Ordering.<Comparable<?>>natural();
236    return copyOf(naturalOrder, elements);
237  }
238
239  /**
240   * Returns an immutable sorted multiset containing the given elements sorted by their natural
241   * ordering.
242   *
243   * <p>This method is not type-safe, as it may be called on elements that are not mutually
244   * comparable.
245   *
246   * @throws ClassCastException if the elements are not mutually comparable
247   * @throws NullPointerException if any of {@code elements} is null
248   */
249  public static <E> ImmutableSortedMultiset<E> copyOf(Iterator<? extends E> elements) {
250    // Hack around E not being a subtype of Comparable.
251    // Unsafe, see ImmutableSortedMultisetFauxverideShim.
252    @SuppressWarnings("unchecked")
253    Ordering<E> naturalOrder = (Ordering<E>) Ordering.<Comparable<?>>natural();
254    return copyOf(naturalOrder, elements);
255  }
256
257  /**
258   * Returns an immutable sorted multiset containing the given elements sorted by the given {@code
259   * Comparator}.
260   *
261   * @throws NullPointerException if {@code comparator} or any of {@code elements} is null
262   */
263  public static <E> ImmutableSortedMultiset<E> copyOf(
264      Comparator<? super E> comparator, Iterator<? extends E> elements) {
265    checkNotNull(comparator);
266    return new Builder<E>(comparator).addAll(elements).build();
267  }
268
269  /**
270   * Returns an immutable sorted multiset containing the given elements sorted by the given {@code
271   * Comparator}. This method iterates over {@code elements} at most once.
272   *
273   * <p>Despite the method name, this method attempts to avoid actually copying the data when it is
274   * safe to do so. The exact circumstances under which a copy will or will not be performed are
275   * undocumented and subject to change.
276   *
277   * @throws NullPointerException if {@code comparator} or any of {@code elements} is null
278   */
279  public static <E> ImmutableSortedMultiset<E> copyOf(
280      Comparator<? super E> comparator, Iterable<? extends E> elements) {
281    if (elements instanceof ImmutableSortedMultiset) {
282      @SuppressWarnings("unchecked") // immutable collections are always safe for covariant casts
283      ImmutableSortedMultiset<E> multiset = (ImmutableSortedMultiset<E>) elements;
284      if (comparator.equals(multiset.comparator())) {
285        if (multiset.isPartialView()) {
286          return copyOfSortedEntries(comparator, multiset.entrySet().asList());
287        } else {
288          return multiset;
289        }
290      }
291    }
292    return new ImmutableSortedMultiset.Builder<E>(comparator).addAll(elements).build();
293  }
294
295  /**
296   * Returns an immutable sorted multiset containing the elements of a sorted multiset, sorted by
297   * the same {@code Comparator}. That behavior differs from {@link #copyOf(Iterable)}, which always
298   * uses the natural ordering of the elements.
299   *
300   * <p>Despite the method name, this method attempts to avoid actually copying the data when it is
301   * safe to do so. The exact circumstances under which a copy will or will not be performed are
302   * undocumented and subject to change.
303   *
304   * <p>This method is safe to use even when {@code sortedMultiset} is a synchronized or concurrent
305   * collection that is currently being modified by another thread.
306   *
307   * @throws NullPointerException if {@code sortedMultiset} or any of its elements is null
308   */
309  public static <E> ImmutableSortedMultiset<E> copyOfSorted(SortedMultiset<E> sortedMultiset) {
310    return copyOfSortedEntries(
311        sortedMultiset.comparator(), Lists.newArrayList(sortedMultiset.entrySet()));
312  }
313
314  private static <E> ImmutableSortedMultiset<E> copyOfSortedEntries(
315      Comparator<? super E> comparator, Collection<Entry<E>> entries) {
316    if (entries.isEmpty()) {
317      return emptyMultiset(comparator);
318    }
319    ImmutableList.Builder<E> elementsBuilder = new ImmutableList.Builder<E>(entries.size());
320    long[] cumulativeCounts = new long[entries.size() + 1];
321    int i = 0;
322    for (Entry<E> entry : entries) {
323      elementsBuilder.add(entry.getElement());
324      cumulativeCounts[i + 1] = cumulativeCounts[i] + entry.getCount();
325      i++;
326    }
327    return new RegularImmutableSortedMultiset<E>(
328        new RegularImmutableSortedSet<E>(elementsBuilder.build(), comparator),
329        cumulativeCounts,
330        0,
331        entries.size());
332  }
333
334  @SuppressWarnings("unchecked")
335  static <E> ImmutableSortedMultiset<E> emptyMultiset(Comparator<? super E> comparator) {
336    if (Ordering.natural().equals(comparator)) {
337      return (ImmutableSortedMultiset<E>) RegularImmutableSortedMultiset.NATURAL_EMPTY_MULTISET;
338    } else {
339      return new RegularImmutableSortedMultiset<E>(comparator);
340    }
341  }
342
343  ImmutableSortedMultiset() {}
344
345  @Override
346  public final Comparator<? super E> comparator() {
347    return elementSet().comparator();
348  }
349
350  @Override
351  public abstract ImmutableSortedSet<E> elementSet();
352
353  @LazyInit @CheckForNull transient ImmutableSortedMultiset<E> descendingMultiset;
354
355  @Override
356  public ImmutableSortedMultiset<E> descendingMultiset() {
357    ImmutableSortedMultiset<E> result = descendingMultiset;
358    if (result == null) {
359      return descendingMultiset =
360          this.isEmpty()
361              ? emptyMultiset(Ordering.from(comparator()).reverse())
362              : new DescendingImmutableSortedMultiset<E>(this);
363    }
364    return result;
365  }
366
367  /**
368   * {@inheritDoc}
369   *
370   * <p>This implementation is guaranteed to throw an {@link UnsupportedOperationException}.
371   *
372   * @throws UnsupportedOperationException always
373   * @deprecated Unsupported operation.
374   */
375  @CanIgnoreReturnValue
376  @Deprecated
377  @Override
378  @DoNotCall("Always throws UnsupportedOperationException")
379  @CheckForNull
380  public final Entry<E> pollFirstEntry() {
381    throw new UnsupportedOperationException();
382  }
383
384  /**
385   * {@inheritDoc}
386   *
387   * <p>This implementation is guaranteed to throw an {@link UnsupportedOperationException}.
388   *
389   * @throws UnsupportedOperationException always
390   * @deprecated Unsupported operation.
391   */
392  @CanIgnoreReturnValue
393  @Deprecated
394  @Override
395  @DoNotCall("Always throws UnsupportedOperationException")
396  @CheckForNull
397  public final Entry<E> pollLastEntry() {
398    throw new UnsupportedOperationException();
399  }
400
401  @Override
402  public abstract ImmutableSortedMultiset<E> headMultiset(E upperBound, BoundType boundType);
403
404  @Override
405  public ImmutableSortedMultiset<E> subMultiset(
406      E lowerBound, BoundType lowerBoundType, E upperBound, BoundType upperBoundType) {
407    checkArgument(
408        comparator().compare(lowerBound, upperBound) <= 0,
409        "Expected lowerBound <= upperBound but %s > %s",
410        lowerBound,
411        upperBound);
412    return tailMultiset(lowerBound, lowerBoundType).headMultiset(upperBound, upperBoundType);
413  }
414
415  @Override
416  public abstract ImmutableSortedMultiset<E> tailMultiset(E lowerBound, BoundType boundType);
417
418  /**
419   * Returns a builder that creates immutable sorted multisets with an explicit comparator. If the
420   * comparator has a more general type than the set being generated, such as creating a {@code
421   * SortedMultiset<Integer>} with a {@code Comparator<Number>}, use the {@link Builder} constructor
422   * instead.
423   *
424   * @throws NullPointerException if {@code comparator} is null
425   */
426  public static <E> Builder<E> orderedBy(Comparator<E> comparator) {
427    return new Builder<E>(comparator);
428  }
429
430  /**
431   * Returns a builder that creates immutable sorted multisets whose elements are ordered by the
432   * reverse of their natural ordering.
433   *
434   * <p>Note: the type parameter {@code E} extends {@code Comparable<?>} rather than {@code
435   * Comparable<? super E>} as a workaround for javac <a
436   * href="http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6468354">bug 6468354</a>.
437   */
438  public static <E extends Comparable<?>> Builder<E> reverseOrder() {
439    return new Builder<E>(Ordering.<E>natural().reverse());
440  }
441
442  /**
443   * Returns a builder that creates immutable sorted multisets whose elements are ordered by their
444   * natural ordering. The sorted multisets use {@link Ordering#natural()} as the comparator. This
445   * method provides more type-safety than {@link #builder}, as it can be called only for classes
446   * that implement {@link Comparable}.
447   *
448   * <p>Note: the type parameter {@code E} extends {@code Comparable<?>} rather than {@code
449   * Comparable<? super E>} as a workaround for javac <a
450   * href="http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6468354">bug 6468354</a>.
451   */
452  public static <E extends Comparable<?>> Builder<E> naturalOrder() {
453    return new Builder<E>(Ordering.natural());
454  }
455
456  /**
457   * A builder for creating immutable multiset instances, especially {@code public static final}
458   * multisets ("constant multisets"). Example:
459   *
460   * <pre>{@code
461   * public static final ImmutableSortedMultiset<Bean> BEANS =
462   *     new ImmutableSortedMultiset.Builder<Bean>(colorComparator())
463   *         .addCopies(Bean.COCOA, 4)
464   *         .addCopies(Bean.GARDEN, 6)
465   *         .addCopies(Bean.RED, 8)
466   *         .addCopies(Bean.BLACK_EYED, 10)
467   *         .build();
468   * }</pre>
469   *
470   * <p>Builder instances can be reused; it is safe to call {@link #build} multiple times to build
471   * multiple multisets in series.
472   *
473   * @since 12.0
474   */
475  public static class Builder<E> extends ImmutableMultiset.Builder<E> {
476    /*
477     * We keep an array of elements and counts.  Periodically -- when we need more room in the
478     * array, or when we're building, or the like -- we sort, deduplicate, and combine the counts.
479     * Negative counts indicate a setCount operation with ~counts[i].
480     */
481
482    private final Comparator<? super E> comparator;
483
484    @VisibleForTesting E[] elements;
485    private int[] counts;
486
487    /*
488     * The number of used positions in the elements array.  We deduplicate periodically, so this
489     * may fluctuate up and down.
490     */
491    private int length;
492
493    // True if we just called build() and the elements array is being used by a created ISM, meaning
494    // we shouldn't modify that array further.
495    private boolean forceCopyElements;
496
497    /**
498     * Creates a new builder. The returned builder is equivalent to the builder generated by {@link
499     * ImmutableSortedMultiset#orderedBy(Comparator)}.
500     */
501    @SuppressWarnings("unchecked")
502    public Builder(Comparator<? super E> comparator) {
503      super(true); // doesn't allocate hash table in supertype
504      this.comparator = checkNotNull(comparator);
505      this.elements = (E[]) new Object[ImmutableCollection.Builder.DEFAULT_INITIAL_CAPACITY];
506      this.counts = new int[ImmutableCollection.Builder.DEFAULT_INITIAL_CAPACITY];
507    }
508
509    /** Check if we need to do deduplication and coalescing, and if so, do it. */
510    private void maintenance() {
511      if (length == elements.length) {
512        dedupAndCoalesce(true);
513      } else if (forceCopyElements) {
514        this.elements = Arrays.copyOf(elements, elements.length);
515        // we don't currently need to copy the counts array, because we don't use it directly
516        // in built ISMs
517      }
518      forceCopyElements = false;
519    }
520
521    private void dedupAndCoalesce(boolean maybeExpand) {
522      if (length == 0) {
523        return;
524      }
525      E[] sortedElements = Arrays.copyOf(elements, length);
526      Arrays.sort(sortedElements, comparator);
527      int uniques = 1;
528      for (int i = 1; i < sortedElements.length; i++) {
529        if (comparator.compare(sortedElements[uniques - 1], sortedElements[i]) < 0) {
530          sortedElements[uniques] = sortedElements[i];
531          uniques++;
532        }
533      }
534      Arrays.fill(sortedElements, uniques, length, null);
535      if (maybeExpand && uniques * 4 > length * 3) {
536        // lots of nonduplicated elements, expand the array by 50%
537        sortedElements =
538            Arrays.copyOf(sortedElements, IntMath.saturatedAdd(length, length / 2 + 1));
539      }
540      int[] sortedCounts = new int[sortedElements.length];
541      for (int i = 0; i < length; i++) {
542        int index = Arrays.binarySearch(sortedElements, 0, uniques, elements[i], comparator);
543        if (counts[i] >= 0) {
544          sortedCounts[index] += counts[i];
545        } else {
546          sortedCounts[index] = ~counts[i];
547        }
548      }
549      // Note that we're not getting rid, yet, of elements with count 0.  We'll do that in build().
550      this.elements = sortedElements;
551      this.counts = sortedCounts;
552      this.length = uniques;
553    }
554
555    /**
556     * Adds {@code element} to the {@code ImmutableSortedMultiset}.
557     *
558     * @param element the element to add
559     * @return this {@code Builder} object
560     * @throws NullPointerException if {@code element} is null
561     */
562    @CanIgnoreReturnValue
563    @Override
564    public Builder<E> add(E element) {
565      return addCopies(element, 1);
566    }
567
568    /**
569     * Adds each element of {@code elements} to the {@code ImmutableSortedMultiset}.
570     *
571     * @param elements the elements to add
572     * @return this {@code Builder} object
573     * @throws NullPointerException if {@code elements} is null or contains a null element
574     */
575    @CanIgnoreReturnValue
576    @Override
577    public Builder<E> add(E... elements) {
578      for (E element : elements) {
579        add(element);
580      }
581      return this;
582    }
583
584    /**
585     * Adds a number of occurrences of an element to this {@code ImmutableSortedMultiset}.
586     *
587     * @param element the element to add
588     * @param occurrences the number of occurrences of the element to add. May be zero, in which
589     *     case no change will be made.
590     * @return this {@code Builder} object
591     * @throws NullPointerException if {@code element} is null
592     * @throws IllegalArgumentException if {@code occurrences} is negative, or if this operation
593     *     would result in more than {@link Integer#MAX_VALUE} occurrences of the element
594     */
595    @CanIgnoreReturnValue
596    @Override
597    public Builder<E> addCopies(E element, int occurrences) {
598      checkNotNull(element);
599      CollectPreconditions.checkNonnegative(occurrences, "occurrences");
600      if (occurrences == 0) {
601        return this;
602      }
603      maintenance();
604      elements[length] = element;
605      counts[length] = occurrences;
606      length++;
607      return this;
608    }
609
610    /**
611     * Adds or removes the necessary occurrences of an element such that the element attains the
612     * desired count.
613     *
614     * @param element the element to add or remove occurrences of
615     * @param count the desired count of the element in this multiset
616     * @return this {@code Builder} object
617     * @throws NullPointerException if {@code element} is null
618     * @throws IllegalArgumentException if {@code count} is negative
619     */
620    @CanIgnoreReturnValue
621    @Override
622    public Builder<E> setCount(E element, int count) {
623      checkNotNull(element);
624      CollectPreconditions.checkNonnegative(count, "count");
625      maintenance();
626      elements[length] = element;
627      counts[length] = ~count;
628      length++;
629      return this;
630    }
631
632    /**
633     * Adds each element of {@code elements} to the {@code ImmutableSortedMultiset}.
634     *
635     * @param elements the {@code Iterable} to add to the {@code ImmutableSortedMultiset}
636     * @return this {@code Builder} object
637     * @throws NullPointerException if {@code elements} is null or contains a null element
638     */
639    @CanIgnoreReturnValue
640    @Override
641    public Builder<E> addAll(Iterable<? extends E> elements) {
642      if (elements instanceof Multiset) {
643        for (Entry<? extends E> entry : ((Multiset<? extends E>) elements).entrySet()) {
644          addCopies(entry.getElement(), entry.getCount());
645        }
646      } else {
647        for (E e : elements) {
648          add(e);
649        }
650      }
651      return this;
652    }
653
654    /**
655     * Adds each element of {@code elements} to the {@code ImmutableSortedMultiset}.
656     *
657     * @param elements the elements to add to the {@code ImmutableSortedMultiset}
658     * @return this {@code Builder} object
659     * @throws NullPointerException if {@code elements} is null or contains a null element
660     */
661    @CanIgnoreReturnValue
662    @Override
663    public Builder<E> addAll(Iterator<? extends E> elements) {
664      while (elements.hasNext()) {
665        add(elements.next());
666      }
667      return this;
668    }
669
670    private void dedupAndCoalesceAndDeleteEmpty() {
671      dedupAndCoalesce(false);
672
673      // If there was a setCount(elem, 0), those elements are still present.  Eliminate them.
674      int size = 0;
675      for (int i = 0; i < length; i++) {
676        if (counts[i] > 0) {
677          elements[size] = elements[i];
678          counts[size] = counts[i];
679          size++;
680        }
681      }
682      Arrays.fill(elements, size, length, null);
683      Arrays.fill(counts, size, length, 0);
684      length = size;
685    }
686
687    /**
688     * Returns a newly-created {@code ImmutableSortedMultiset} based on the contents of the {@code
689     * Builder}.
690     */
691    @Override
692    public ImmutableSortedMultiset<E> build() {
693      dedupAndCoalesceAndDeleteEmpty();
694      if (length == 0) {
695        return emptyMultiset(comparator);
696      }
697      RegularImmutableSortedSet<E> elementSet =
698          (RegularImmutableSortedSet<E>) ImmutableSortedSet.construct(comparator, length, elements);
699      long[] cumulativeCounts = new long[length + 1];
700      for (int i = 0; i < length; i++) {
701        cumulativeCounts[i + 1] = cumulativeCounts[i] + counts[i];
702      }
703      forceCopyElements = true;
704      return new RegularImmutableSortedMultiset<E>(elementSet, cumulativeCounts, 0, length);
705    }
706  }
707
708  @J2ktIncompatible // serialization
709  private static final class SerializedForm<E> implements Serializable {
710    final Comparator<? super E> comparator;
711    final E[] elements;
712    final int[] counts;
713
714    @SuppressWarnings("unchecked")
715    SerializedForm(SortedMultiset<E> multiset) {
716      this.comparator = multiset.comparator();
717      int n = multiset.entrySet().size();
718      elements = (E[]) new Object[n];
719      counts = new int[n];
720      int i = 0;
721      for (Entry<E> entry : multiset.entrySet()) {
722        elements[i] = entry.getElement();
723        counts[i] = entry.getCount();
724        i++;
725      }
726    }
727
728    Object readResolve() {
729      int n = elements.length;
730      Builder<E> builder = new Builder<>(comparator);
731      for (int i = 0; i < n; i++) {
732        builder.addCopies(elements[i], counts[i]);
733      }
734      return builder.build();
735    }
736  }
737
738  @Override
739  @J2ktIncompatible // serialization
740  Object writeReplace() {
741    return new SerializedForm<E>(this);
742  }
743
744  @J2ktIncompatible // java.io.ObjectInputStream
745  private void readObject(ObjectInputStream stream) throws InvalidObjectException {
746    throw new InvalidObjectException("Use SerializedForm");
747  }
748
749  /**
750   * Not supported. Use {@link #toImmutableSortedMultiset} instead. This method exists only to hide
751   * {@link ImmutableMultiset#toImmutableMultiset} from consumers of {@code
752   * ImmutableSortedMultiset}.
753   *
754   * @throws UnsupportedOperationException always
755   * @deprecated Use {@link ImmutableSortedMultiset#toImmutableSortedMultiset}.
756   */
757  @DoNotCall("Use toImmutableSortedMultiset.")
758  @Deprecated
759  @SuppressWarnings({"AndroidJdkLibsChecker", "Java7ApiChecker"})
760  @IgnoreJRERequirement // Users will use this only if they're already using streams.
761  static <E> Collector<E, ?, ImmutableMultiset<E>> toImmutableMultiset() {
762    throw new UnsupportedOperationException();
763  }
764
765  /**
766   * Not supported. Use {@link #toImmutableSortedMultiset} instead. This method exists only to hide
767   * {@link ImmutableMultiset#toImmutableMultiset} from consumers of {@code
768   * ImmutableSortedMultiset}.
769   *
770   * @throws UnsupportedOperationException always
771   * @deprecated Use {@link ImmutableSortedMultiset#toImmutableSortedMultiset}.
772   */
773  @DoNotCall("Use toImmutableSortedMultiset.")
774  @Deprecated
775  @SuppressWarnings({"AndroidJdkLibsChecker", "Java7ApiChecker"})
776  @IgnoreJRERequirement // Users will use this only if they're already using streams.
777  static <T extends @Nullable Object, E> Collector<T, ?, ImmutableMultiset<E>> toImmutableMultiset(
778      Function<? super T, ? extends E> elementFunction, ToIntFunction<? super T> countFunction) {
779    throw new UnsupportedOperationException();
780  }
781
782  /**
783   * Not supported. Use {@link #naturalOrder}, which offers better type-safety, instead. This method
784   * exists only to hide {@link ImmutableMultiset#builder} from consumers of {@code
785   * ImmutableSortedMultiset}.
786   *
787   * @throws UnsupportedOperationException always
788   * @deprecated Use {@link ImmutableSortedMultiset#naturalOrder}, which offers better type-safety.
789   */
790  @DoNotCall("Use naturalOrder.")
791  @Deprecated
792  public static <E> ImmutableSortedMultiset.Builder<E> builder() {
793    throw new UnsupportedOperationException();
794  }
795
796  /**
797   * Not supported. <b>You are attempting to create a multiset that may contain a non-{@code
798   * Comparable} element.</b> Proper calls will resolve to the version in {@code
799   * ImmutableSortedMultiset}, not this dummy version.
800   *
801   * @throws UnsupportedOperationException always
802   * @deprecated <b>Pass a parameter of type {@code Comparable} to use {@link
803   *     ImmutableSortedMultiset#of(Comparable)}.</b>
804   */
805  @DoNotCall("Elements must be Comparable. (Or, pass a Comparator to orderedBy or copyOf.)")
806  @Deprecated
807  public static <E> ImmutableSortedMultiset<E> of(E element) {
808    throw new UnsupportedOperationException();
809  }
810
811  /**
812   * Not supported. <b>You are attempting to create a multiset that may contain a non-{@code
813   * Comparable} element.</b> Proper calls will resolve to the version in {@code
814   * ImmutableSortedMultiset}, not this dummy version.
815   *
816   * @throws UnsupportedOperationException always
817   * @deprecated <b>Pass the parameters of type {@code Comparable} to use {@link
818   *     ImmutableSortedMultiset#of(Comparable, Comparable)}.</b>
819   */
820  @DoNotCall("Elements must be Comparable. (Or, pass a Comparator to orderedBy or copyOf.)")
821  @Deprecated
822  public static <E> ImmutableSortedMultiset<E> of(E e1, E e2) {
823    throw new UnsupportedOperationException();
824  }
825
826  /**
827   * Not supported. <b>You are attempting to create a multiset that may contain a non-{@code
828   * Comparable} element.</b> Proper calls will resolve to the version in {@code
829   * ImmutableSortedMultiset}, not this dummy version.
830   *
831   * @throws UnsupportedOperationException always
832   * @deprecated <b>Pass the parameters of type {@code Comparable} to use {@link
833   *     ImmutableSortedMultiset#of(Comparable, Comparable, Comparable)}.</b>
834   */
835  @DoNotCall("Elements must be Comparable. (Or, pass a Comparator to orderedBy or copyOf.)")
836  @Deprecated
837  public static <E> ImmutableSortedMultiset<E> of(E e1, E e2, E e3) {
838    throw new UnsupportedOperationException();
839  }
840
841  /**
842   * Not supported. <b>You are attempting to create a multiset that may contain a non-{@code
843   * Comparable} element.</b> Proper calls will resolve to the version in {@code
844   * ImmutableSortedMultiset}, not this dummy version.
845   *
846   * @throws UnsupportedOperationException always
847   * @deprecated <b>Pass the parameters of type {@code Comparable} to use {@link
848   *     ImmutableSortedMultiset#of(Comparable, Comparable, Comparable, Comparable)}. </b>
849   */
850  @DoNotCall("Elements must be Comparable. (Or, pass a Comparator to orderedBy or copyOf.)")
851  @Deprecated
852  public static <E> ImmutableSortedMultiset<E> of(E e1, E e2, E e3, E e4) {
853    throw new UnsupportedOperationException();
854  }
855
856  /**
857   * Not supported. <b>You are attempting to create a multiset that may contain a non-{@code
858   * Comparable} element.</b> Proper calls will resolve to the version in {@code
859   * ImmutableSortedMultiset}, not this dummy version.
860   *
861   * @throws UnsupportedOperationException always
862   * @deprecated <b>Pass the parameters of type {@code Comparable} to use {@link
863   *     ImmutableSortedMultiset#of(Comparable, Comparable, Comparable, Comparable, Comparable)} .
864   *     </b>
865   */
866  @DoNotCall("Elements must be Comparable. (Or, pass a Comparator to orderedBy or copyOf.)")
867  @Deprecated
868  public static <E> ImmutableSortedMultiset<E> of(E e1, E e2, E e3, E e4, E e5) {
869    throw new UnsupportedOperationException();
870  }
871
872  /**
873   * Not supported. <b>You are attempting to create a multiset that may contain a non-{@code
874   * Comparable} element.</b> Proper calls will resolve to the version in {@code
875   * ImmutableSortedMultiset}, not this dummy version.
876   *
877   * @throws UnsupportedOperationException always
878   * @deprecated <b>Pass the parameters of type {@code Comparable} to use {@link
879   *     ImmutableSortedMultiset#of(Comparable, Comparable, Comparable, Comparable, Comparable,
880   *     Comparable, Comparable...)} . </b>
881   */
882  @DoNotCall("Elements must be Comparable. (Or, pass a Comparator to orderedBy or copyOf.)")
883  @Deprecated
884  public static <E> ImmutableSortedMultiset<E> of(
885      E e1, E e2, E e3, E e4, E e5, E e6, E... remaining) {
886    throw new UnsupportedOperationException();
887  }
888
889  /**
890   * Not supported. <b>You are attempting to create a multiset that may contain non-{@code
891   * Comparable} elements.</b> Proper calls will resolve to the version in {@code
892   * ImmutableSortedMultiset}, not this dummy version.
893   *
894   * @throws UnsupportedOperationException always
895   * @deprecated <b>Pass parameters of type {@code Comparable} to use {@link
896   *     ImmutableSortedMultiset#copyOf(Comparable[])}.</b>
897   */
898  @DoNotCall("Elements must be Comparable. (Or, pass a Comparator to orderedBy or copyOf.)")
899  @Deprecated
900  // The usage of "Z" here works around bugs in Javadoc (JDK-8318093) and JDiff.
901  public static <Z> ImmutableSortedMultiset<Z> copyOf(Z[] elements) {
902    throw new UnsupportedOperationException();
903  }
904
905  private static final long serialVersionUID = 0xdecaf;
906}