ImmutableSortedSet.java
/*
* 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.google.common.collect;
import static com.google.common.base.Preconditions.checkArgument;
import static com.google.common.base.Preconditions.checkNotNull;
import static com.google.common.collect.ObjectArrays.checkElementsNotNull;
import com.google.common.annotations.GwtCompatible;
import com.google.common.annotations.GwtIncompatible;
import com.google.errorprone.annotations.CanIgnoreReturnValue;
import com.google.errorprone.annotations.DoNotCall;
import com.google.errorprone.annotations.concurrent.LazyInit;
import java.io.InvalidObjectException;
import java.io.ObjectInputStream;
import java.io.Serializable;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.Comparator;
import java.util.Iterator;
import java.util.NavigableSet;
import java.util.SortedSet;
import java.util.Spliterator;
import java.util.Spliterators;
import java.util.function.Consumer;
import java.util.stream.Collector;
import org.checkerframework.checker.nullness.qual.Nullable;
/**
* A {@link NavigableSet} whose contents will never change, with many other important properties
* detailed at {@link ImmutableCollection}.
*
* <p><b>Warning:</b> as with any sorted collection, you are strongly advised not to use a {@link
* Comparator} or {@link Comparable} type whose comparison behavior is <i>inconsistent with
* equals</i>. That is, {@code a.compareTo(b)} or {@code comparator.compare(a, b)} should equal zero
* <i>if and only if</i> {@code a.equals(b)}. If this advice is not followed, the resulting
* collection will not correctly obey its specification.
*
* <p>See the Guava User Guide article on <a href=
* "https://github.com/google/guava/wiki/ImmutableCollectionsExplained"> immutable collections</a>.
*
* @author Jared Levy
* @author Louis Wasserman
* @since 2.0 (implements {@code NavigableSet} since 12.0)
*/
// TODO(benyu): benchmark and optimize all creation paths, which are a mess now
@GwtCompatible(serializable = true, emulated = true)
@SuppressWarnings("serial") // we're overriding default serialization
public abstract class ImmutableSortedSet<E> extends ImmutableSortedSetFauxverideShim<E>
implements NavigableSet<E>, SortedIterable<E> {
static final int SPLITERATOR_CHARACTERISTICS =
ImmutableSet.SPLITERATOR_CHARACTERISTICS | Spliterator.SORTED;
/**
* Returns a {@code Collector} that accumulates the input elements into a new {@code
* ImmutableSortedSet}, ordered by the specified comparator.
*
* <p>If the elements contain duplicates (according to the comparator), only the first duplicate
* in encounter order will appear in the result.
*
* @since 21.0
*/
public static <E> Collector<E, ?, ImmutableSortedSet<E>> toImmutableSortedSet(
Comparator<? super E> comparator) {
return CollectCollectors.toImmutableSortedSet(comparator);
}
static <E> RegularImmutableSortedSet<E> emptySet(Comparator<? super E> comparator) {
if (Ordering.natural().equals(comparator)) {
return (RegularImmutableSortedSet<E>) RegularImmutableSortedSet.NATURAL_EMPTY_SET;
} else {
return new RegularImmutableSortedSet<E>(ImmutableList.<E>of(), comparator);
}
}
/**
* Returns the empty immutable sorted set.
*
* <p><b>Performance note:</b> the instance returned is a singleton.
*/
public static <E> ImmutableSortedSet<E> of() {
return (ImmutableSortedSet<E>) RegularImmutableSortedSet.NATURAL_EMPTY_SET;
}
/** Returns an immutable sorted set containing a single element. */
public static <E extends Comparable<? super E>> ImmutableSortedSet<E> of(E element) {
return new RegularImmutableSortedSet<E>(ImmutableList.of(element), Ordering.natural());
}
/**
* Returns an immutable sorted set containing the given elements sorted by their natural ordering.
* When multiple elements are equivalent according to {@link Comparable#compareTo}, only the first
* one specified is included.
*
* @throws NullPointerException if any element is null
*/
@SuppressWarnings("unchecked")
public static <E extends Comparable<? super E>> ImmutableSortedSet<E> of(E e1, E e2) {
return construct(Ordering.natural(), 2, e1, e2);
}
/**
* Returns an immutable sorted set containing the given elements sorted by their natural ordering.
* When multiple elements are equivalent according to {@link Comparable#compareTo}, only the first
* one specified is included.
*
* @throws NullPointerException if any element is null
*/
@SuppressWarnings("unchecked")
public static <E extends Comparable<? super E>> ImmutableSortedSet<E> of(E e1, E e2, E e3) {
return construct(Ordering.natural(), 3, e1, e2, e3);
}
/**
* Returns an immutable sorted set containing the given elements sorted by their natural ordering.
* When multiple elements are equivalent according to {@link Comparable#compareTo}, only the first
* one specified is included.
*
* @throws NullPointerException if any element is null
*/
@SuppressWarnings("unchecked")
public static <E extends Comparable<? super E>> ImmutableSortedSet<E> of(E e1, E e2, E e3, E e4) {
return construct(Ordering.natural(), 4, e1, e2, e3, e4);
}
/**
* Returns an immutable sorted set containing the given elements sorted by their natural ordering.
* When multiple elements are equivalent according to {@link Comparable#compareTo}, only the first
* one specified is included.
*
* @throws NullPointerException if any element is null
*/
@SuppressWarnings("unchecked")
public static <E extends Comparable<? super E>> ImmutableSortedSet<E> of(
E e1, E e2, E e3, E e4, E e5) {
return construct(Ordering.natural(), 5, e1, e2, e3, e4, e5);
}
/**
* Returns an immutable sorted set containing the given elements sorted by their natural ordering.
* When multiple elements are equivalent according to {@link Comparable#compareTo}, only the first
* one specified is included.
*
* @throws NullPointerException if any element is null
* @since 3.0 (source-compatible since 2.0)
*/
@SuppressWarnings("unchecked")
public static <E extends Comparable<? super E>> ImmutableSortedSet<E> of(
E e1, E e2, E e3, E e4, E e5, E e6, E... remaining) {
Comparable[] contents = new Comparable[6 + remaining.length];
contents[0] = e1;
contents[1] = e2;
contents[2] = e3;
contents[3] = e4;
contents[4] = e5;
contents[5] = e6;
System.arraycopy(remaining, 0, contents, 6, remaining.length);
return construct(Ordering.natural(), contents.length, (E[]) contents);
}
// TODO(kevinb): Consider factory methods that reject duplicates
/**
* Returns an immutable sorted set containing the given elements sorted by their natural ordering.
* When multiple elements are equivalent according to {@link Comparable#compareTo}, only the first
* one specified is included.
*
* @throws NullPointerException if any of {@code elements} is null
* @since 3.0
*/
public static <E extends Comparable<? super E>> ImmutableSortedSet<E> copyOf(E[] elements) {
return construct(Ordering.natural(), elements.length, elements.clone());
}
/**
* Returns an immutable sorted set containing the given elements sorted by their natural ordering.
* When multiple elements are equivalent according to {@code compareTo()}, only the first one
* specified is included. To create a copy of a {@code SortedSet} that preserves the comparator,
* call {@link #copyOfSorted} instead. This method iterates over {@code elements} at most once.
*
* <p>Note that if {@code s} is a {@code Set<String>}, then {@code ImmutableSortedSet.copyOf(s)}
* returns an {@code ImmutableSortedSet<String>} containing each of the strings in {@code s},
* while {@code ImmutableSortedSet.of(s)} returns an {@code ImmutableSortedSet<Set<String>>}
* containing one element (the given set itself).
*
* <p>Despite the method name, this method attempts to avoid actually copying the data when it is
* safe to do so. The exact circumstances under which a copy will or will not be performed are
* undocumented and subject to change.
*
* <p>This method is not type-safe, as it may be called on elements that are not mutually
* comparable.
*
* @throws ClassCastException if the elements are not mutually comparable
* @throws NullPointerException if any of {@code elements} is null
*/
public static <E> ImmutableSortedSet<E> copyOf(Iterable<? extends E> elements) {
// Hack around E not being a subtype of Comparable.
// Unsafe, see ImmutableSortedSetFauxverideShim.
@SuppressWarnings("unchecked")
Ordering<E> naturalOrder = (Ordering<E>) Ordering.<Comparable>natural();
return copyOf(naturalOrder, elements);
}
/**
* Returns an immutable sorted set containing the given elements sorted by their natural ordering.
* When multiple elements are equivalent according to {@code compareTo()}, only the first one
* specified is included. To create a copy of a {@code SortedSet} that preserves the comparator,
* call {@link #copyOfSorted} instead. This method iterates over {@code elements} at most once.
*
* <p>Note that if {@code s} is a {@code Set<String>}, then {@code ImmutableSortedSet.copyOf(s)}
* returns an {@code ImmutableSortedSet<String>} containing each of the strings in {@code s},
* while {@code ImmutableSortedSet.of(s)} returns an {@code ImmutableSortedSet<Set<String>>}
* containing one element (the given set itself).
*
* <p><b>Note:</b> Despite what the method name suggests, if {@code elements} is an {@code
* ImmutableSortedSet}, it may be returned instead of a copy.
*
* <p>This method is not type-safe, as it may be called on elements that are not mutually
* comparable.
*
* <p>This method is safe to use even when {@code elements} is a synchronized or concurrent
* collection that is currently being modified by another thread.
*
* @throws ClassCastException if the elements are not mutually comparable
* @throws NullPointerException if any of {@code elements} is null
* @since 7.0 (source-compatible since 2.0)
*/
public static <E> ImmutableSortedSet<E> copyOf(Collection<? extends E> elements) {
// Hack around E not being a subtype of Comparable.
// Unsafe, see ImmutableSortedSetFauxverideShim.
@SuppressWarnings("unchecked")
Ordering<E> naturalOrder = (Ordering<E>) Ordering.<Comparable>natural();
return copyOf(naturalOrder, elements);
}
/**
* Returns an immutable sorted set containing the given elements sorted by their natural ordering.
* When multiple elements are equivalent according to {@code compareTo()}, only the first one
* specified is included.
*
* <p>This method is not type-safe, as it may be called on elements that are not mutually
* comparable.
*
* @throws ClassCastException if the elements are not mutually comparable
* @throws NullPointerException if any of {@code elements} is null
*/
public static <E> ImmutableSortedSet<E> copyOf(Iterator<? extends E> elements) {
// Hack around E not being a subtype of Comparable.
// Unsafe, see ImmutableSortedSetFauxverideShim.
@SuppressWarnings("unchecked")
Ordering<E> naturalOrder = (Ordering<E>) Ordering.<Comparable>natural();
return copyOf(naturalOrder, elements);
}
/**
* Returns an immutable sorted set containing the given elements sorted by the given {@code
* Comparator}. When multiple elements are equivalent according to {@code compareTo()}, only the
* first one specified is included.
*
* @throws NullPointerException if {@code comparator} or any of {@code elements} is null
*/
public static <E> ImmutableSortedSet<E> copyOf(
Comparator<? super E> comparator, Iterator<? extends E> elements) {
return new Builder<E>(comparator).addAll(elements).build();
}
/**
* Returns an immutable sorted set containing the given elements sorted by the given {@code
* Comparator}. When multiple elements are equivalent according to {@code compare()}, only the
* first one specified is included. This method iterates over {@code elements} at most once.
*
* <p>Despite the method name, this method attempts to avoid actually copying the data when it is
* safe to do so. The exact circumstances under which a copy will or will not be performed are
* undocumented and subject to change.
*
* @throws NullPointerException if {@code comparator} or any of {@code elements} is null
*/
public static <E> ImmutableSortedSet<E> copyOf(
Comparator<? super E> comparator, Iterable<? extends E> elements) {
checkNotNull(comparator);
boolean hasSameComparator = SortedIterables.hasSameComparator(comparator, elements);
if (hasSameComparator && (elements instanceof ImmutableSortedSet)) {
@SuppressWarnings("unchecked")
ImmutableSortedSet<E> original = (ImmutableSortedSet<E>) elements;
if (!original.isPartialView()) {
return original;
}
}
@SuppressWarnings("unchecked") // elements only contains E's; it's safe.
E[] array = (E[]) Iterables.toArray(elements);
return construct(comparator, array.length, array);
}
/**
* Returns an immutable sorted set containing the given elements sorted by the given {@code
* Comparator}. When multiple elements are equivalent according to {@code compareTo()}, only the
* first one specified is included.
*
* <p>Despite the method name, this method attempts to avoid actually copying the data when it is
* safe to do so. The exact circumstances under which a copy will or will not be performed are
* undocumented and subject to change.
*
* <p>This method is safe to use even when {@code elements} is a synchronized or concurrent
* collection that is currently being modified by another thread.
*
* @throws NullPointerException if {@code comparator} or any of {@code elements} is null
* @since 7.0 (source-compatible since 2.0)
*/
public static <E> ImmutableSortedSet<E> copyOf(
Comparator<? super E> comparator, Collection<? extends E> elements) {
return copyOf(comparator, (Iterable<? extends E>) elements);
}
/**
* Returns an immutable sorted set containing the elements of a sorted set, sorted by the same
* {@code Comparator}. That behavior differs from {@link #copyOf(Iterable)}, which always uses the
* natural ordering of the elements.
*
* <p>Despite the method name, this method attempts to avoid actually copying the data when it is
* safe to do so. The exact circumstances under which a copy will or will not be performed are
* undocumented and subject to change.
*
* <p>This method is safe to use even when {@code sortedSet} is a synchronized or concurrent
* collection that is currently being modified by another thread.
*
* @throws NullPointerException if {@code sortedSet} or any of its elements is null
*/
public static <E> ImmutableSortedSet<E> copyOfSorted(SortedSet<E> sortedSet) {
Comparator<? super E> comparator = SortedIterables.comparator(sortedSet);
ImmutableList<E> list = ImmutableList.copyOf(sortedSet);
if (list.isEmpty()) {
return emptySet(comparator);
} else {
return new RegularImmutableSortedSet<E>(list, comparator);
}
}
/**
* Constructs an {@code ImmutableSortedSet} from the first {@code n} elements of {@code contents}.
* If {@code k} is the size of the returned {@code ImmutableSortedSet}, then the sorted unique
* elements are in the first {@code k} positions of {@code contents}, and {@code contents[i] ==
* null} for {@code k <= i < n}.
*
* <p>If {@code k == contents.length}, then {@code contents} may no longer be safe for
* modification.
*
* @throws NullPointerException if any of the first {@code n} elements of {@code contents} is null
*/
static <E> ImmutableSortedSet<E> construct(
Comparator<? super E> comparator, int n, E... contents) {
if (n == 0) {
return emptySet(comparator);
}
checkElementsNotNull(contents, n);
Arrays.sort(contents, 0, n, comparator);
int uniques = 1;
for (int i = 1; i < n; i++) {
E cur = contents[i];
E prev = contents[uniques - 1];
if (comparator.compare(cur, prev) != 0) {
contents[uniques++] = cur;
}
}
Arrays.fill(contents, uniques, n, null);
return new RegularImmutableSortedSet<E>(
ImmutableList.<E>asImmutableList(contents, uniques), comparator);
}
/**
* Returns a builder that creates immutable sorted sets with an explicit comparator. If the
* comparator has a more general type than the set being generated, such as creating a {@code
* SortedSet<Integer>} with a {@code Comparator<Number>}, use the {@link Builder} constructor
* instead.
*
* @throws NullPointerException if {@code comparator} is null
*/
public static <E> Builder<E> orderedBy(Comparator<E> comparator) {
return new Builder<E>(comparator);
}
/**
* Returns a builder that creates immutable sorted sets whose elements are ordered by the reverse
* of their natural ordering.
*/
public static <E extends Comparable<?>> Builder<E> reverseOrder() {
return new Builder<E>(Collections.reverseOrder());
}
/**
* Returns a builder that creates immutable sorted sets whose elements are ordered by their
* natural ordering. The sorted sets use {@link Ordering#natural()} as the comparator. This method
* provides more type-safety than {@link #builder}, as it can be called only for classes that
* implement {@link Comparable}.
*/
public static <E extends Comparable<?>> Builder<E> naturalOrder() {
return new Builder<E>(Ordering.natural());
}
/**
* A builder for creating immutable sorted set instances, especially {@code public static final}
* sets ("constant sets"), with a given comparator. Example:
*
* <pre>{@code
* public static final ImmutableSortedSet<Number> LUCKY_NUMBERS =
* new ImmutableSortedSet.Builder<Number>(ODDS_FIRST_COMPARATOR)
* .addAll(SINGLE_DIGIT_PRIMES)
* .add(42)
* .build();
* }</pre>
*
* <p>Builder instances can be reused; it is safe to call {@link #build} multiple times to build
* multiple sets in series. Each set is a superset of the set created before it.
*
* @since 2.0
*/
public static final class Builder<E> extends ImmutableSet.Builder<E> {
private final Comparator<? super E> comparator;
private E[] elements;
private int n;
/**
* Creates a new builder. The returned builder is equivalent to the builder generated by {@link
* ImmutableSortedSet#orderedBy}.
*/
public Builder(Comparator<? super E> comparator) {
super(true); // don't construct guts of hash-based set builder
this.comparator = checkNotNull(comparator);
this.elements = (E[]) new Object[ImmutableCollection.Builder.DEFAULT_INITIAL_CAPACITY];
this.n = 0;
}
@Override
void copy() {
elements = Arrays.copyOf(elements, elements.length);
}
private void sortAndDedup() {
if (n == 0) {
return;
}
Arrays.sort(elements, 0, n, comparator);
int unique = 1;
for (int i = 1; i < n; i++) {
int cmp = comparator.compare(elements[unique - 1], elements[i]);
if (cmp < 0) {
elements[unique++] = elements[i];
} else if (cmp > 0) {
throw new AssertionError(
"Comparator " + comparator + " compare method violates its contract");
}
}
Arrays.fill(elements, unique, n, null);
n = unique;
}
/**
* Adds {@code element} to the {@code ImmutableSortedSet}. If the {@code ImmutableSortedSet}
* already contains {@code element}, then {@code add} has no effect. (only the previously added
* element is retained).
*
* @param element the element to add
* @return this {@code Builder} object
* @throws NullPointerException if {@code element} is null
*/
@CanIgnoreReturnValue
@Override
public Builder<E> add(E element) {
checkNotNull(element);
copyIfNecessary();
if (n == elements.length) {
sortAndDedup();
/*
* Sorting operations can only be allowed to occur once every O(n) operations to keep
* amortized O(n log n) performance. Therefore, ensure there are at least O(n) *unused*
* spaces in the builder array.
*/
int newLength = ImmutableCollection.Builder.expandedCapacity(n, n + 1);
if (newLength > elements.length) {
elements = Arrays.copyOf(elements, newLength);
}
}
elements[n++] = element;
return this;
}
/**
* Adds each element of {@code elements} to the {@code ImmutableSortedSet}, ignoring duplicate
* elements (only the first duplicate element is added).
*
* @param elements the elements to add
* @return this {@code Builder} object
* @throws NullPointerException if {@code elements} contains a null element
*/
@CanIgnoreReturnValue
@Override
public Builder<E> add(E... elements) {
checkElementsNotNull(elements);
for (E e : elements) {
add(e);
}
return this;
}
/**
* Adds each element of {@code elements} to the {@code ImmutableSortedSet}, ignoring duplicate
* elements (only the first duplicate element is added).
*
* @param elements the elements to add to the {@code ImmutableSortedSet}
* @return this {@code Builder} object
* @throws NullPointerException if {@code elements} contains a null element
*/
@CanIgnoreReturnValue
@Override
public Builder<E> addAll(Iterable<? extends E> elements) {
super.addAll(elements);
return this;
}
/**
* Adds each element of {@code elements} to the {@code ImmutableSortedSet}, ignoring duplicate
* elements (only the first duplicate element is added).
*
* @param elements the elements to add to the {@code ImmutableSortedSet}
* @return this {@code Builder} object
* @throws NullPointerException if {@code elements} contains a null element
*/
@CanIgnoreReturnValue
@Override
public Builder<E> addAll(Iterator<? extends E> elements) {
super.addAll(elements);
return this;
}
@CanIgnoreReturnValue
@Override
Builder<E> combine(ImmutableSet.Builder<E> builder) {
copyIfNecessary();
Builder<E> other = (Builder<E>) builder;
for (int i = 0; i < other.n; i++) {
add(other.elements[i]);
}
return this;
}
/**
* Returns a newly-created {@code ImmutableSortedSet} based on the contents of the {@code
* Builder} and its comparator.
*/
@Override
public ImmutableSortedSet<E> build() {
sortAndDedup();
if (n == 0) {
return emptySet(comparator);
} else {
forceCopy = true;
return new RegularImmutableSortedSet<E>(
ImmutableList.asImmutableList(elements, n), comparator);
}
}
}
int unsafeCompare(Object a, Object b) {
return unsafeCompare(comparator, a, b);
}
static int unsafeCompare(Comparator<?> comparator, Object a, Object b) {
// Pretend the comparator can compare anything. If it turns out it can't
// compare a and b, we should get a CCE on the subsequent line. Only methods
// that are spec'd to throw CCE should call this.
@SuppressWarnings("unchecked")
Comparator<Object> unsafeComparator = (Comparator<Object>) comparator;
return unsafeComparator.compare(a, b);
}
final transient Comparator<? super E> comparator;
ImmutableSortedSet(Comparator<? super E> comparator) {
this.comparator = comparator;
}
/**
* Returns the comparator that orders the elements, which is {@link Ordering#natural()} when the
* natural ordering of the elements is used. Note that its behavior is not consistent with {@link
* SortedSet#comparator()}, which returns {@code null} to indicate natural ordering.
*/
@Override
public Comparator<? super E> comparator() {
return comparator;
}
@Override // needed to unify the iterator() methods in Collection and SortedIterable
public abstract UnmodifiableIterator<E> iterator();
/**
* {@inheritDoc}
*
* <p>This method returns a serializable {@code ImmutableSortedSet}.
*
* <p>The {@link SortedSet#headSet} documentation states that a subset of a subset throws an
* {@link IllegalArgumentException} if passed a {@code toElement} greater than an earlier {@code
* toElement}. However, this method doesn't throw an exception in that situation, but instead
* keeps the original {@code toElement}.
*/
@Override
public ImmutableSortedSet<E> headSet(E toElement) {
return headSet(toElement, false);
}
/** @since 12.0 */
@Override
public ImmutableSortedSet<E> headSet(E toElement, boolean inclusive) {
return headSetImpl(checkNotNull(toElement), inclusive);
}
/**
* {@inheritDoc}
*
* <p>This method returns a serializable {@code ImmutableSortedSet}.
*
* <p>The {@link SortedSet#subSet} documentation states that a subset of a subset throws an {@link
* IllegalArgumentException} if passed a {@code fromElement} smaller than an earlier {@code
* fromElement}. However, this method doesn't throw an exception in that situation, but instead
* keeps the original {@code fromElement}. Similarly, this method keeps the original {@code
* toElement}, instead of throwing an exception, if passed a {@code toElement} greater than an
* earlier {@code toElement}.
*/
@Override
public ImmutableSortedSet<E> subSet(E fromElement, E toElement) {
return subSet(fromElement, true, toElement, false);
}
/** @since 12.0 */
@GwtIncompatible // NavigableSet
@Override
public ImmutableSortedSet<E> subSet(
E fromElement, boolean fromInclusive, E toElement, boolean toInclusive) {
checkNotNull(fromElement);
checkNotNull(toElement);
checkArgument(comparator.compare(fromElement, toElement) <= 0);
return subSetImpl(fromElement, fromInclusive, toElement, toInclusive);
}
/**
* {@inheritDoc}
*
* <p>This method returns a serializable {@code ImmutableSortedSet}.
*
* <p>The {@link SortedSet#tailSet} documentation states that a subset of a subset throws an
* {@link IllegalArgumentException} if passed a {@code fromElement} smaller than an earlier {@code
* fromElement}. However, this method doesn't throw an exception in that situation, but instead
* keeps the original {@code fromElement}.
*/
@Override
public ImmutableSortedSet<E> tailSet(E fromElement) {
return tailSet(fromElement, true);
}
/** @since 12.0 */
@Override
public ImmutableSortedSet<E> tailSet(E fromElement, boolean inclusive) {
return tailSetImpl(checkNotNull(fromElement), inclusive);
}
/*
* These methods perform most headSet, subSet, and tailSet logic, besides
* parameter validation.
*/
abstract ImmutableSortedSet<E> headSetImpl(E toElement, boolean inclusive);
abstract ImmutableSortedSet<E> subSetImpl(
E fromElement, boolean fromInclusive, E toElement, boolean toInclusive);
abstract ImmutableSortedSet<E> tailSetImpl(E fromElement, boolean inclusive);
/** @since 12.0 */
@GwtIncompatible // NavigableSet
@Override
public E lower(E e) {
return Iterators.getNext(headSet(e, false).descendingIterator(), null);
}
/** @since 12.0 */
@Override
public E floor(E e) {
return Iterators.getNext(headSet(e, true).descendingIterator(), null);
}
/** @since 12.0 */
@Override
public E ceiling(E e) {
return Iterables.getFirst(tailSet(e, true), null);
}
/** @since 12.0 */
@GwtIncompatible // NavigableSet
@Override
public E higher(E e) {
return Iterables.getFirst(tailSet(e, false), null);
}
@Override
public E first() {
return iterator().next();
}
@Override
public E last() {
return descendingIterator().next();
}
/**
* Guaranteed to throw an exception and leave the set unmodified.
*
* @since 12.0
* @throws UnsupportedOperationException always
* @deprecated Unsupported operation.
*/
@CanIgnoreReturnValue
@Deprecated
@GwtIncompatible // NavigableSet
@Override
@DoNotCall("Always throws UnsupportedOperationException")
public final E pollFirst() {
throw new UnsupportedOperationException();
}
/**
* Guaranteed to throw an exception and leave the set unmodified.
*
* @since 12.0
* @throws UnsupportedOperationException always
* @deprecated Unsupported operation.
*/
@CanIgnoreReturnValue
@Deprecated
@GwtIncompatible // NavigableSet
@Override
@DoNotCall("Always throws UnsupportedOperationException")
public final E pollLast() {
throw new UnsupportedOperationException();
}
@GwtIncompatible // NavigableSet
@LazyInit
transient ImmutableSortedSet<E> descendingSet;
/** @since 12.0 */
@GwtIncompatible // NavigableSet
@Override
public ImmutableSortedSet<E> descendingSet() {
// racy single-check idiom
ImmutableSortedSet<E> result = descendingSet;
if (result == null) {
result = descendingSet = createDescendingSet();
result.descendingSet = this;
}
return result;
}
// Most classes should implement this as new DescendingImmutableSortedSet<E>(this),
// but we push down that implementation because ProGuard can't eliminate it even when it's always
// overridden.
@GwtIncompatible // NavigableSet
abstract ImmutableSortedSet<E> createDescendingSet();
@Override
public Spliterator<E> spliterator() {
return new Spliterators.AbstractSpliterator<E>(
size(), SPLITERATOR_CHARACTERISTICS | Spliterator.SIZED) {
final UnmodifiableIterator<E> iterator = iterator();
@Override
public boolean tryAdvance(Consumer<? super E> action) {
if (iterator.hasNext()) {
action.accept(iterator.next());
return true;
} else {
return false;
}
}
@Override
public Comparator<? super E> getComparator() {
return comparator;
}
};
}
/** @since 12.0 */
@GwtIncompatible // NavigableSet
@Override
public abstract UnmodifiableIterator<E> descendingIterator();
/** Returns the position of an element within the set, or -1 if not present. */
abstract int indexOf(@Nullable Object target);
/*
* This class is used to serialize all ImmutableSortedSet instances,
* regardless of implementation type. It captures their "logical contents"
* only. This is necessary to ensure that the existence of a particular
* implementation type is an implementation detail.
*/
private static class SerializedForm<E> implements Serializable {
final Comparator<? super E> comparator;
final Object[] elements;
public SerializedForm(Comparator<? super E> comparator, Object[] elements) {
this.comparator = comparator;
this.elements = elements;
}
@SuppressWarnings("unchecked")
Object readResolve() {
return new Builder<E>(comparator).add((E[]) elements).build();
}
private static final long serialVersionUID = 0;
}
private void readObject(ObjectInputStream unused) throws InvalidObjectException {
throw new InvalidObjectException("Use SerializedForm");
}
@Override
Object writeReplace() {
return new SerializedForm<E>(comparator, toArray());
}
}