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/*
 * Copyright (C) 2008 The Guava Authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.facebook.presto.jdbc.internal.guava.collect;

import static com.facebook.presto.jdbc.internal.guava.base.Preconditions.checkNotNull;

import com.facebook.presto.jdbc.internal.guava.annotations.Beta;
import com.facebook.presto.jdbc.internal.guava.annotations.GwtCompatible;
import com.facebook.presto.jdbc.internal.guava.annotations.GwtIncompatible;
import com.facebook.presto.jdbc.internal.guava.annotations.VisibleForTesting;
import com.google.errorprone.annotations.CanIgnoreReturnValue;
import com.google.errorprone.annotations.concurrent.LazyInit;
import com.facebook.presto.jdbc.internal.j2objc.annotations.WeakOuter;
import java.io.Serializable;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import java.util.function.Function;
import java.util.function.ToIntFunction;
import java.util.stream.Collector;
import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * A {@link Multiset} whose contents will never change, with many other important properties
 * detailed at {@link ImmutableCollection}.
 *
 * 

Grouped iteration. In all current implementations, duplicate elements always appear * consecutively when iterating. Elements iterate in order by the first appearance of that * element when the multiset was created. * *

See the Guava User Guide article on immutable collections. * * @author Jared Levy * @author Louis Wasserman * @since 2.0 */ @GwtCompatible(serializable = true, emulated = true) @SuppressWarnings("serial") // we're overriding default serialization public abstract class ImmutableMultiset extends ImmutableMultisetGwtSerializationDependencies implements Multiset { /** * Returns a {@code Collector} that accumulates the input elements into a new {@code * ImmutableMultiset}. Elements iterate in order by the first appearance of that element in * encounter order. * * @since 21.0 */ @Beta public static Collector> toImmutableMultiset() { return toImmutableMultiset(Function.identity(), e -> 1); } /** * Returns a {@code Collector} that accumulates elements into an {@code ImmutableMultiset} whose * elements are the result of applying {@code elementFunction} to the inputs, with counts equal to * the result of applying {@code countFunction} to the inputs. * *

If the mapped elements contain duplicates (according to {@link Object#equals}), the first * occurrence in encounter order appears in the resulting multiset, with count equal to the sum of * the outputs of {@code countFunction.applyAsInt(t)} for each {@code t} mapped to that element. * * @since 22.0 */ public static Collector> toImmutableMultiset( Function elementFunction, ToIntFunction countFunction) { checkNotNull(elementFunction); checkNotNull(countFunction); return Collector.of( LinkedHashMultiset::create, (multiset, t) -> multiset.add(checkNotNull(elementFunction.apply(t)), countFunction.applyAsInt(t)), (multiset1, multiset2) -> { multiset1.addAll(multiset2); return multiset1; }, (Multiset multiset) -> copyFromEntries(multiset.entrySet())); } /** Returns the empty immutable multiset. */ @SuppressWarnings("unchecked") // all supported methods are covariant public static ImmutableMultiset of() { return (ImmutableMultiset) RegularImmutableMultiset.EMPTY; } /** * Returns an immutable multiset containing a single element. * * @throws NullPointerException if {@code element} is null * @since 6.0 (source-compatible since 2.0) */ @SuppressWarnings("unchecked") // generic array created but never written public static ImmutableMultiset of(E element) { return copyFromElements(element); } /** * Returns an immutable multiset containing the given elements, in order. * * @throws NullPointerException if any element is null * @since 6.0 (source-compatible since 2.0) */ @SuppressWarnings("unchecked") // public static ImmutableMultiset of(E e1, E e2) { return copyFromElements(e1, e2); } /** * Returns an immutable multiset containing the given elements, in the "grouped iteration order" * described in the class documentation. * * @throws NullPointerException if any element is null * @since 6.0 (source-compatible since 2.0) */ @SuppressWarnings("unchecked") // public static ImmutableMultiset of(E e1, E e2, E e3) { return copyFromElements(e1, e2, e3); } /** * Returns an immutable multiset containing the given elements, in the "grouped iteration order" * described in the class documentation. * * @throws NullPointerException if any element is null * @since 6.0 (source-compatible since 2.0) */ @SuppressWarnings("unchecked") // public static ImmutableMultiset of(E e1, E e2, E e3, E e4) { return copyFromElements(e1, e2, e3, e4); } /** * Returns an immutable multiset containing the given elements, in the "grouped iteration order" * described in the class documentation. * * @throws NullPointerException if any element is null * @since 6.0 (source-compatible since 2.0) */ @SuppressWarnings("unchecked") // public static ImmutableMultiset of(E e1, E e2, E e3, E e4, E e5) { return copyFromElements(e1, e2, e3, e4, e5); } /** * Returns an immutable multiset containing the given elements, in the "grouped iteration order" * described in the class documentation. * * @throws NullPointerException if any element is null * @since 6.0 (source-compatible since 2.0) */ @SuppressWarnings("unchecked") // public static ImmutableMultiset of(E e1, E e2, E e3, E e4, E e5, E e6, E... others) { return new Builder().add(e1).add(e2).add(e3).add(e4).add(e5).add(e6).add(others).build(); } /** * Returns an immutable multiset containing the given elements, in the "grouped iteration order" * described in the class documentation. * * @throws NullPointerException if any of {@code elements} is null * @since 6.0 */ public static ImmutableMultiset copyOf(E[] elements) { return copyFromElements(elements); } /** * Returns an immutable multiset containing the given elements, in the "grouped iteration order" * described in the class documentation. * * @throws NullPointerException if any of {@code elements} is null */ public static ImmutableMultiset copyOf(Iterable elements) { if (elements instanceof ImmutableMultiset) { @SuppressWarnings("unchecked") // all supported methods are covariant ImmutableMultiset result = (ImmutableMultiset) elements; if (!result.isPartialView()) { return result; } } Multiset multiset = (elements instanceof Multiset) ? Multisets.cast(elements) : LinkedHashMultiset.create(elements); return copyFromEntries(multiset.entrySet()); } /** * Returns an immutable multiset containing the given elements, in the "grouped iteration order" * described in the class documentation. * * @throws NullPointerException if any of {@code elements} is null */ public static ImmutableMultiset copyOf(Iterator elements) { Multiset multiset = LinkedHashMultiset.create(); Iterators.addAll(multiset, elements); return copyFromEntries(multiset.entrySet()); } private static ImmutableMultiset copyFromElements(E... elements) { Multiset multiset = LinkedHashMultiset.create(); Collections.addAll(multiset, elements); return copyFromEntries(multiset.entrySet()); } static ImmutableMultiset copyFromEntries( Collection> entries) { if (entries.isEmpty()) { return of(); } else { return RegularImmutableMultiset.create(entries); } } ImmutableMultiset() {} @Override public UnmodifiableIterator iterator() { final Iterator> entryIterator = entrySet().iterator(); return new UnmodifiableIterator() { int remaining; @MonotonicNonNull E element; @Override public boolean hasNext() { return (remaining > 0) || entryIterator.hasNext(); } @Override public E next() { if (remaining <= 0) { Entry entry = entryIterator.next(); element = entry.getElement(); remaining = entry.getCount(); } remaining--; return element; } }; } @LazyInit private transient ImmutableList asList; @Override public ImmutableList asList() { ImmutableList result = asList; return (result == null) ? asList = super.asList() : result; } @Override public boolean contains(@Nullable Object object) { return count(object) > 0; } /** * Guaranteed to throw an exception and leave the collection unmodified. * * @throws UnsupportedOperationException always * @deprecated Unsupported operation. */ @CanIgnoreReturnValue @Deprecated @Override public final int add(E element, int occurrences) { throw new UnsupportedOperationException(); } /** * Guaranteed to throw an exception and leave the collection unmodified. * * @throws UnsupportedOperationException always * @deprecated Unsupported operation. */ @CanIgnoreReturnValue @Deprecated @Override public final int remove(Object element, int occurrences) { throw new UnsupportedOperationException(); } /** * Guaranteed to throw an exception and leave the collection unmodified. * * @throws UnsupportedOperationException always * @deprecated Unsupported operation. */ @CanIgnoreReturnValue @Deprecated @Override public final int setCount(E element, int count) { throw new UnsupportedOperationException(); } /** * Guaranteed to throw an exception and leave the collection unmodified. * * @throws UnsupportedOperationException always * @deprecated Unsupported operation. */ @CanIgnoreReturnValue @Deprecated @Override public final boolean setCount(E element, int oldCount, int newCount) { throw new UnsupportedOperationException(); } @GwtIncompatible // not present in emulated superclass @Override int copyIntoArray(Object[] dst, int offset) { for (Multiset.Entry entry : entrySet()) { Arrays.fill(dst, offset, offset + entry.getCount(), entry.getElement()); offset += entry.getCount(); } return offset; } @Override public boolean equals(@Nullable Object object) { return Multisets.equalsImpl(this, object); } @Override public int hashCode() { return Sets.hashCodeImpl(entrySet()); } @Override public String toString() { return entrySet().toString(); } /** @since 21.0 (present with return type {@code Set} since 2.0) */ @Override public abstract ImmutableSet elementSet(); @LazyInit private transient ImmutableSet> entrySet; @Override public ImmutableSet> entrySet() { ImmutableSet> es = entrySet; return (es == null) ? (entrySet = createEntrySet()) : es; } private ImmutableSet> createEntrySet() { return isEmpty() ? ImmutableSet.>of() : new EntrySet(); } abstract Entry getEntry(int index); @WeakOuter private final class EntrySet extends IndexedImmutableSet> { @Override boolean isPartialView() { return ImmutableMultiset.this.isPartialView(); } @Override Entry get(int index) { return getEntry(index); } @Override public int size() { return elementSet().size(); } @Override public boolean contains(Object o) { if (o instanceof Entry) { Entry entry = (Entry) o; if (entry.getCount() <= 0) { return false; } int count = count(entry.getElement()); return count == entry.getCount(); } return false; } @Override public int hashCode() { return ImmutableMultiset.this.hashCode(); } @GwtIncompatible @Override Object writeReplace() { return new EntrySetSerializedForm(ImmutableMultiset.this); } private static final long serialVersionUID = 0; } @GwtIncompatible static class EntrySetSerializedForm implements Serializable { final ImmutableMultiset multiset; EntrySetSerializedForm(ImmutableMultiset multiset) { this.multiset = multiset; } Object readResolve() { return multiset.entrySet(); } } @GwtIncompatible @Override Object writeReplace() { return new SerializedForm(this); } /** * Returns a new builder. The generated builder is equivalent to the builder created by the {@link * Builder} constructor. */ public static Builder builder() { return new Builder(); } /** * A builder for creating immutable multiset instances, especially {@code public static final} * multisets ("constant multisets"). Example: * *

{@code
   * public static final ImmutableMultiset BEANS =
   *     new ImmutableMultiset.Builder()
   *         .addCopies(Bean.COCOA, 4)
   *         .addCopies(Bean.GARDEN, 6)
   *         .addCopies(Bean.RED, 8)
   *         .addCopies(Bean.BLACK_EYED, 10)
   *         .build();
   * }
* *

Builder instances can be reused; it is safe to call {@link #build} multiple times to build * multiple multisets in series. * * @since 2.0 */ public static class Builder extends ImmutableCollection.Builder { final Multiset contents; /** * Creates a new builder. The returned builder is equivalent to the builder generated by {@link * ImmutableMultiset#builder}. */ public Builder() { this(LinkedHashMultiset.create()); } Builder(Multiset contents) { this.contents = contents; } /** * Adds {@code element} to the {@code ImmutableMultiset}. * * @param element the element to add * @return this {@code Builder} object * @throws NullPointerException if {@code element} is null */ @CanIgnoreReturnValue @Override public Builder add(E element) { contents.add(checkNotNull(element)); return this; } /** * Adds each element of {@code elements} to the {@code ImmutableMultiset}. * * @param elements the elements to add * @return this {@code Builder} object * @throws NullPointerException if {@code elements} is null or contains a null element */ @CanIgnoreReturnValue @Override public Builder add(E... elements) { super.add(elements); return this; } /** * Adds a number of occurrences of an element to this {@code ImmutableMultiset}. * * @param element the element to add * @param occurrences the number of occurrences of the element to add. May be zero, in which * case no change will be made. * @return this {@code Builder} object * @throws NullPointerException if {@code element} is null * @throws IllegalArgumentException if {@code occurrences} is negative, or if this operation * would result in more than {@link Integer#MAX_VALUE} occurrences of the element */ @CanIgnoreReturnValue public Builder addCopies(E element, int occurrences) { contents.add(checkNotNull(element), occurrences); return this; } /** * Adds or removes the necessary occurrences of an element such that the element attains the * desired count. * * @param element the element to add or remove occurrences of * @param count the desired count of the element in this multiset * @return this {@code Builder} object * @throws NullPointerException if {@code element} is null * @throws IllegalArgumentException if {@code count} is negative */ @CanIgnoreReturnValue public Builder setCount(E element, int count) { contents.setCount(checkNotNull(element), count); return this; } /** * Adds each element of {@code elements} to the {@code ImmutableMultiset}. * * @param elements the {@code Iterable} to add to the {@code ImmutableMultiset} * @return this {@code Builder} object * @throws NullPointerException if {@code elements} is null or contains a null element */ @CanIgnoreReturnValue @Override public Builder addAll(Iterable elements) { if (elements instanceof Multiset) { Multiset multiset = Multisets.cast(elements); multiset.forEachEntry((e, n) -> contents.add(checkNotNull(e), n)); } else { super.addAll(elements); } return this; } /** * Adds each element of {@code elements} to the {@code ImmutableMultiset}. * * @param elements the elements to add to the {@code ImmutableMultiset} * @return this {@code Builder} object * @throws NullPointerException if {@code elements} is null or contains a null element */ @CanIgnoreReturnValue @Override public Builder addAll(Iterator elements) { super.addAll(elements); return this; } /** * Returns a newly-created {@code ImmutableMultiset} based on the contents of the {@code * Builder}. */ @Override public ImmutableMultiset build() { return copyOf(contents); } @VisibleForTesting ImmutableMultiset buildJdkBacked() { if (contents.isEmpty()) { return of(); } return JdkBackedImmutableMultiset.create(contents.entrySet()); } } static final class ElementSet extends ImmutableSet.Indexed { private final List> entries; // TODO(cpovirk): @Weak? private final Multiset delegate; ElementSet(List> entries, Multiset delegate) { this.entries = entries; this.delegate = delegate; } @Override E get(int index) { return entries.get(index).getElement(); } @Override public boolean contains(@Nullable Object object) { return delegate.contains(object); } @Override boolean isPartialView() { return true; } @Override public int size() { return entries.size(); } } static final class SerializedForm implements Serializable { final Object[] elements; final int[] counts; SerializedForm(Multiset multiset) { int distinct = multiset.entrySet().size(); elements = new Object[distinct]; counts = new int[distinct]; int i = 0; for (Entry entry : multiset.entrySet()) { elements[i] = entry.getElement(); counts[i] = entry.getCount(); i++; } } Object readResolve() { LinkedHashMultiset multiset = LinkedHashMultiset.create(elements.length); for (int i = 0; i < elements.length; i++) { multiset.add(elements[i], counts[i]); } return ImmutableMultiset.copyOf(multiset); } private static final long serialVersionUID = 0; } }