/* __ __ __ __ __ ___
* \ \ / / \ \ / / __/
* \ \/ / /\ \ \/ / /
* \____/__/ \__\____/__/.ɪᴏ
* ᶜᵒᵖʸʳᶦᵍʰᵗ ᵇʸ ᵛᵃᵛʳ ⁻ ˡᶦᶜᵉⁿˢᵉᵈ ᵘⁿᵈᵉʳ ᵗʰᵉ ᵃᵖᵃᶜʰᵉ ˡᶦᶜᵉⁿˢᵉ ᵛᵉʳˢᶦᵒⁿ ᵗʷᵒ ᵈᵒᵗ ᶻᵉʳᵒ
*/
package io.vavr.collection;
import io.vavr.*;
import io.vavr.control.Option;
import java.io.*;
import java.util.ArrayList;
import java.util.Comparator;
import java.util.NoSuchElementException;
import java.util.Objects;
import java.util.function.*;
import java.util.stream.Collector;
/**
* An immutable {@code HashSet} implementation.
*
* @param <T> Component type
* @author Ruslan Sennov, Patryk Najda, Daniel Dietrich
*/
public final class HashSet<T> implements Set<T>, Serializable {
private static final long serialVersionUID = 1L;
private static final HashSet<?> EMPTY = new HashSet<>(HashArrayMappedTrie.empty());
private final HashArrayMappedTrie<T, T> tree;
private HashSet(HashArrayMappedTrie<T, T> tree) {
this.tree = tree;
}
@SuppressWarnings("unchecked")
public static <T> HashSet<T> empty() {
return (HashSet<T>) EMPTY;
}
/**
* Returns a {@link java.util.stream.Collector} which may be used in conjunction with
* {@link java.util.stream.Stream#collect(java.util.stream.Collector)} to obtain a {@link HashSet}.
*
* @param <T> Component type of the HashSet.
* @return A io.vavr.collection.HashSet Collector.
*/
public static <T> Collector<T, ArrayList<T>, HashSet<T>> collector() {
final Supplier<ArrayList<T>> supplier = ArrayList::new;
final BiConsumer<ArrayList<T>, T> accumulator = ArrayList::add;
final BinaryOperator<ArrayList<T>> combiner = (left, right) -> {
left.addAll(right);
return left;
};
final Function<ArrayList<T>, HashSet<T>> finisher = HashSet::ofAll;
return Collector.of(supplier, accumulator, combiner, finisher);
}
/**
* Narrows a widened {@code HashSet<? extends T>} to {@code HashSet<T>}
* by performing a type-safe cast. This is eligible because immutable/read-only
* collections are covariant.
*
* @param hashSet A {@code HashSet}.
* @param <T> Component type of the {@code HashSet}.
* @return the given {@code hashSet} instance as narrowed type {@code HashSet<T>}.
*/
@SuppressWarnings("unchecked")
public static <T> HashSet<T> narrow(HashSet<? extends T> hashSet) {
return (HashSet<T>) hashSet;
}
/**
* Returns a singleton {@code HashSet}, i.e. a {@code HashSet} of one element.
*
* @param element An element.
* @param <T> The component type
* @return A new HashSet instance containing the given element
*/
public static <T> HashSet<T> of(T element) {
return HashSet.<T> empty().add(element);
}
/**
* Creates a HashSet of the given elements.
*
* <pre><code>HashSet.of(1, 2, 3, 4)</code></pre>
*
* @param <T> Component type of the HashSet.
* @param elements Zero or more elements.
* @return A set containing the given elements.
* @throws NullPointerException if {@code elements} is null
*/
@SafeVarargs
public static <T> HashSet<T> of(T... elements) {
Objects.requireNonNull(elements, "elements is null");
HashArrayMappedTrie<T, T> tree = HashArrayMappedTrie.empty();
for (T element : elements) {
tree = tree.put(element, element);
}
return tree.isEmpty() ? empty() : new HashSet<>(tree);
}
/**
* Returns an HashSet containing {@code n} values of a given Function {@code f}
* over a range of integer values from 0 to {@code n - 1}.
*
* @param <T> Component type of the HashSet
* @param n The number of elements in the HashSet
* @param f The Function computing element values
* @return An HashSet consisting of elements {@code f(0),f(1), ..., f(n - 1)}
* @throws NullPointerException if {@code f} is null
*/
public static <T> HashSet<T> tabulate(int n, Function<? super Integer, ? extends T> f) {
Objects.requireNonNull(f, "f is null");
return Collections.tabulate(n, f, HashSet.empty(), HashSet::of);
}
/**
* Returns an HashSet containing {@code n} values supplied by a given Supplier {@code s}.
*
* @param <T> Component type of the HashSet
* @param n The number of elements in the HashSet
* @param s The Supplier computing element values
* @return An HashSet of size {@code n}, where each element contains the result supplied by {@code s}.
* @throws NullPointerException if {@code s} is null
*/
public static <T> HashSet<T> fill(int n, Supplier<? extends T> s) {
Objects.requireNonNull(s, "s is null");
return Collections.fill(n, s, HashSet.empty(), HashSet::of);
}
/**
* Creates a HashSet of the given elements.
*
* @param elements Set elements
* @param <T> The value type
* @return A new HashSet containing the given entries
*/
@SuppressWarnings("unchecked")
public static <T> HashSet<T> ofAll(Iterable<? extends T> elements) {
Objects.requireNonNull(elements, "elements is null");
if (elements instanceof HashSet) {
return (HashSet<T>) elements;
} else {
final HashArrayMappedTrie<T, T> tree = addAll(HashArrayMappedTrie.empty(), elements);
return tree.isEmpty() ? empty() : new HashSet<>(tree);
}
}
/**
* Creates a HashSet that contains the elements of the given {@link java.util.stream.Stream}.
*
* @param javaStream A {@link java.util.stream.Stream}
* @param <T> Component type of the Stream.
* @return A HashSet containing the given elements in the same order.
*/
public static <T> HashSet<T> ofAll(java.util.stream.Stream<? extends T> javaStream) {
Objects.requireNonNull(javaStream, "javaStream is null");
return HashSet.ofAll(Iterator.ofAll(javaStream.iterator()));
}
/**
* Creates a HashSet from boolean values.
*
* @param elements boolean values
* @return A new HashSet of Boolean values
* @throws NullPointerException if elements is null
*/
public static HashSet<Boolean> ofAll(boolean... elements) {
Objects.requireNonNull(elements, "elements is null");
return HashSet.ofAll(Iterator.ofAll(elements));
}
/**
* Creates a HashSet from byte values.
*
* @param elements byte values
* @return A new HashSet of Byte values
* @throws NullPointerException if elements is null
*/
public static HashSet<Byte> ofAll(byte... elements) {
Objects.requireNonNull(elements, "elements is null");
return HashSet.ofAll(Iterator.ofAll(elements));
}
/**
* Creates a HashSet from char values.
*
* @param elements char values
* @return A new HashSet of Character values
* @throws NullPointerException if elements is null
*/
public static HashSet<Character> ofAll(char... elements) {
Objects.requireNonNull(elements, "elements is null");
return HashSet.ofAll(Iterator.ofAll(elements));
}
/**
* Creates a HashSet from double values.
*
* @param elements double values
* @return A new HashSet of Double values
* @throws NullPointerException if elements is null
*/
public static HashSet<Double> ofAll(double... elements) {
Objects.requireNonNull(elements, "elements is null");
return HashSet.ofAll(Iterator.ofAll(elements));
}
/**
* Creates a HashSet from float values.
*
* @param elements float values
* @return A new HashSet of Float values
* @throws NullPointerException if elements is null
*/
public static HashSet<Float> ofAll(float... elements) {
Objects.requireNonNull(elements, "elements is null");
return HashSet.ofAll(Iterator.ofAll(elements));
}
/**
* Creates a HashSet from int values.
*
* @param elements int values
* @return A new HashSet of Integer values
* @throws NullPointerException if elements is null
*/
public static HashSet<Integer> ofAll(int... elements) {
Objects.requireNonNull(elements, "elements is null");
return HashSet.ofAll(Iterator.ofAll(elements));
}
/**
* Creates a HashSet from long values.
*
* @param elements long values
* @return A new HashSet of Long values
* @throws NullPointerException if elements is null
*/
public static HashSet<Long> ofAll(long... elements) {
Objects.requireNonNull(elements, "elements is null");
return HashSet.ofAll(Iterator.ofAll(elements));
}
/**
* Creates a HashSet from short values.
*
* @param elements short values
* @return A new HashSet of Short values
* @throws NullPointerException if elements is null
*/
public static HashSet<Short> ofAll(short... elements) {
Objects.requireNonNull(elements, "elements is null");
return HashSet.ofAll(Iterator.ofAll(elements));
}
/**
* Creates a HashSet of int numbers starting from {@code from}, extending to {@code toExclusive - 1}.
* <p>
* Examples:
* <pre>
* <code>
* HashSet.range(0, 0) // = HashSet()
* HashSet.range(2, 0) // = HashSet()
* HashSet.range(-2, 2) // = HashSet(-2, -1, 0, 1)
* </code>
* </pre>
*
* @param from the first number
* @param toExclusive the last number + 1
* @return a range of int values as specified or the empty range if {@code from >= toExclusive}
*/
public static HashSet<Integer> range(int from, int toExclusive) {
return HashSet.ofAll(Iterator.range(from, toExclusive));
}
public static HashSet<Character> range(char from, char toExclusive) {
return HashSet.ofAll(Iterator.range(from, toExclusive));
}
/**
* Creates a HashSet of int numbers starting from {@code from}, extending to {@code toExclusive - 1},
* with {@code step}.
* <p>
* Examples:
* <pre>
* <code>
* HashSet.rangeBy(1, 3, 1) // = HashSet(1, 2)
* HashSet.rangeBy(1, 4, 2) // = HashSet(1, 3)
* HashSet.rangeBy(4, 1, -2) // = HashSet(4, 2)
* HashSet.rangeBy(4, 1, 2) // = HashSet()
* </code>
* </pre>
*
* @param from the first number
* @param toExclusive the last number + 1
* @param step the step
* @return a range of long values as specified or the empty range if<br>
* {@code from >= toInclusive} and {@code step > 0} or<br>
* {@code from <= toInclusive} and {@code step < 0}
* @throws IllegalArgumentException if {@code step} is zero
*/
public static HashSet<Integer> rangeBy(int from, int toExclusive, int step) {
return HashSet.ofAll(Iterator.rangeBy(from, toExclusive, step));
}
public static HashSet<Character> rangeBy(char from, char toExclusive, int step) {
return HashSet.ofAll(Iterator.rangeBy(from, toExclusive, step));
}
@GwtIncompatible
public static HashSet<Double> rangeBy(double from, double toExclusive, double step) {
return HashSet.ofAll(Iterator.rangeBy(from, toExclusive, step));
}
/**
* Creates a HashSet of long numbers starting from {@code from}, extending to {@code toExclusive - 1}.
* <p>
* Examples:
* <pre>
* <code>
* HashSet.range(0L, 0L) // = HashSet()
* HashSet.range(2L, 0L) // = HashSet()
* HashSet.range(-2L, 2L) // = HashSet(-2L, -1L, 0L, 1L)
* </code>
* </pre>
*
* @param from the first number
* @param toExclusive the last number + 1
* @return a range of long values as specified or the empty range if {@code from >= toExclusive}
*/
public static HashSet<Long> range(long from, long toExclusive) {
return HashSet.ofAll(Iterator.range(from, toExclusive));
}
/**
* Creates a HashSet of long numbers starting from {@code from}, extending to {@code toExclusive - 1},
* with {@code step}.
* <p>
* Examples:
* <pre>
* <code>
* HashSet.rangeBy(1L, 3L, 1L) // = HashSet(1L, 2L)
* HashSet.rangeBy(1L, 4L, 2L) // = HashSet(1L, 3L)
* HashSet.rangeBy(4L, 1L, -2L) // = HashSet(4L, 2L)
* HashSet.rangeBy(4L, 1L, 2L) // = HashSet()
* </code>
* </pre>
*
* @param from the first number
* @param toExclusive the last number + 1
* @param step the step
* @return a range of long values as specified or the empty range if<br>
* {@code from >= toInclusive} and {@code step > 0} or<br>
* {@code from <= toInclusive} and {@code step < 0}
* @throws IllegalArgumentException if {@code step} is zero
*/
public static HashSet<Long> rangeBy(long from, long toExclusive, long step) {
return HashSet.ofAll(Iterator.rangeBy(from, toExclusive, step));
}
/**
* Creates a HashSet of int numbers starting from {@code from}, extending to {@code toInclusive}.
* <p>
* Examples:
* <pre>
* <code>
* HashSet.rangeClosed(0, 0) // = HashSet(0)
* HashSet.rangeClosed(2, 0) // = HashSet()
* HashSet.rangeClosed(-2, 2) // = HashSet(-2, -1, 0, 1, 2)
* </code>
* </pre>
*
* @param from the first number
* @param toInclusive the last number
* @return a range of int values as specified or the empty range if {@code from > toInclusive}
*/
public static HashSet<Integer> rangeClosed(int from, int toInclusive) {
return HashSet.ofAll(Iterator.rangeClosed(from, toInclusive));
}
public static HashSet<Character> rangeClosed(char from, char toInclusive) {
return HashSet.ofAll(Iterator.rangeClosed(from, toInclusive));
}
/**
* Creates a HashSet of int numbers starting from {@code from}, extending to {@code toInclusive},
* with {@code step}.
* <p>
* Examples:
* <pre>
* <code>
* HashSet.rangeClosedBy(1, 3, 1) // = HashSet(1, 2, 3)
* HashSet.rangeClosedBy(1, 4, 2) // = HashSet(1, 3)
* HashSet.rangeClosedBy(4, 1, -2) // = HashSet(4, 2)
* HashSet.rangeClosedBy(4, 1, 2) // = HashSet()
* </code>
* </pre>
*
* @param from the first number
* @param toInclusive the last number
* @param step the step
* @return a range of int values as specified or the empty range if<br>
* {@code from > toInclusive} and {@code step > 0} or<br>
* {@code from < toInclusive} and {@code step < 0}
* @throws IllegalArgumentException if {@code step} is zero
*/
public static HashSet<Integer> rangeClosedBy(int from, int toInclusive, int step) {
return HashSet.ofAll(Iterator.rangeClosedBy(from, toInclusive, step));
}
public static HashSet<Character> rangeClosedBy(char from, char toInclusive, int step) {
return HashSet.ofAll(Iterator.rangeClosedBy(from, toInclusive, step));
}
@GwtIncompatible
public static HashSet<Double> rangeClosedBy(double from, double toInclusive, double step) {
return HashSet.ofAll(Iterator.rangeClosedBy(from, toInclusive, step));
}
/**
* Creates a HashSet of long numbers starting from {@code from}, extending to {@code toInclusive}.
* <p>
* Examples:
* <pre>
* <code>
* HashSet.rangeClosed(0L, 0L) // = HashSet(0L)
* HashSet.rangeClosed(2L, 0L) // = HashSet()
* HashSet.rangeClosed(-2L, 2L) // = HashSet(-2L, -1L, 0L, 1L, 2L)
* </code>
* </pre>
*
* @param from the first number
* @param toInclusive the last number
* @return a range of long values as specified or the empty range if {@code from > toInclusive}
*/
public static HashSet<Long> rangeClosed(long from, long toInclusive) {
return HashSet.ofAll(Iterator.rangeClosed(from, toInclusive));
}
/**
* Creates a HashSet of long numbers starting from {@code from}, extending to {@code toInclusive},
* with {@code step}.
* <p>
* Examples:
* <pre>
* <code>
* HashSet.rangeClosedBy(1L, 3L, 1L) // = HashSet(1L, 2L, 3L)
* HashSet.rangeClosedBy(1L, 4L, 2L) // = HashSet(1L, 3L)
* HashSet.rangeClosedBy(4L, 1L, -2L) // = HashSet(4L, 2L)
* HashSet.rangeClosedBy(4L, 1L, 2L) // = HashSet()
* </code>
* </pre>
*
* @param from the first number
* @param toInclusive the last number
* @param step the step
* @return a range of int values as specified or the empty range if<br>
* {@code from > toInclusive} and {@code step > 0} or<br>
* {@code from < toInclusive} and {@code step < 0}
* @throws IllegalArgumentException if {@code step} is zero
*/
public static HashSet<Long> rangeClosedBy(long from, long toInclusive, long step) {
return HashSet.ofAll(Iterator.rangeClosedBy(from, toInclusive, step));
}
@Override
public HashSet<T> add(T element) {
return contains(element) ? this : new HashSet<>(tree.put(element, element));
}
@Override
public HashSet<T> addAll(Iterable<? extends T> elements) {
Objects.requireNonNull(elements, "elements is null");
if (isEmpty() && elements instanceof HashSet) {
@SuppressWarnings("unchecked")
final HashSet<T> set = (HashSet<T>) elements;
return set;
}
final HashArrayMappedTrie<T, T> that = addAll(tree, elements);
if (that.size() == tree.size()) {
return this;
} else {
return new HashSet<>(that);
}
}
@Override
public <R> HashSet<R> collect(PartialFunction<? super T, ? extends R> partialFunction) {
return ofAll(iterator().<R> collect(partialFunction));
}
@Override
public boolean contains(T element) {
return tree.get(element).isDefined();
}
@Override
public HashSet<T> diff(Set<? extends T> elements) {
Objects.requireNonNull(elements, "elements is null");
if (isEmpty() || elements.isEmpty()) {
return this;
} else {
return removeAll(elements);
}
}
@Override
public HashSet<T> distinct() {
return this;
}
@Override
public HashSet<T> distinctBy(Comparator<? super T> comparator) {
Objects.requireNonNull(comparator, "comparator is null");
return HashSet.ofAll(iterator().distinctBy(comparator));
}
@Override
public <U> HashSet<T> distinctBy(Function<? super T, ? extends U> keyExtractor) {
Objects.requireNonNull(keyExtractor, "keyExtractor is null");
return HashSet.ofAll(iterator().distinctBy(keyExtractor));
}
@Override
public HashSet<T> drop(int n) {
if (n <= 0) {
return this;
} else {
return HashSet.ofAll(iterator().drop(n));
}
}
@Override
public HashSet<T> dropRight(int n) {
return drop(n);
}
@Override
public HashSet<T> dropUntil(Predicate<? super T> predicate) {
Objects.requireNonNull(predicate, "predicate is null");
return dropWhile(predicate.negate());
}
@Override
public HashSet<T> dropWhile(Predicate<? super T> predicate) {
Objects.requireNonNull(predicate, "predicate is null");
final HashSet<T> dropped = HashSet.ofAll(iterator().dropWhile(predicate));
return dropped.length() == length() ? this : dropped;
}
@Override
public HashSet<T> filter(Predicate<? super T> predicate) {
Objects.requireNonNull(predicate, "predicate is null");
final HashSet<T> filtered = HashSet.ofAll(iterator().filter(predicate));
if (filtered.isEmpty()) {
return empty();
} else if (filtered.length() == length()) {
return this;
} else {
return filtered;
}
}
@Override
public <U> HashSet<U> flatMap(Function<? super T, ? extends Iterable<? extends U>> mapper) {
Objects.requireNonNull(mapper, "mapper is null");
if (isEmpty()) {
return empty();
} else {
final HashArrayMappedTrie<U, U> that = foldLeft(HashArrayMappedTrie.empty(),
(tree, t) -> addAll(tree, mapper.apply(t)));
return new HashSet<>(that);
}
}
@Override
public <U> U foldRight(U zero, BiFunction<? super T, ? super U, ? extends U> f) {
return foldLeft(zero, (u, t) -> f.apply(t, u));
}
@Override
public <C> Map<C, HashSet<T>> groupBy(Function<? super T, ? extends C> classifier) {
return Collections.groupBy(this, classifier, HashSet::ofAll);
}
@Override
public Iterator<HashSet<T>> grouped(int size) {
return sliding(size, size);
}
@Override
public boolean hasDefiniteSize() {
return true;
}
@Override
public T head() {
if (tree.isEmpty()) {
throw new NoSuchElementException("head of empty set");
}
return iterator().next();
}
@Override
public Option<T> headOption() {
return iterator().headOption();
}
@Override
public HashSet<T> init() {
return tail();
}
@Override
public Option<HashSet<T>> initOption() {
return tailOption();
}
@Override
public HashSet<T> intersect(Set<? extends T> elements) {
Objects.requireNonNull(elements, "elements is null");
if (isEmpty() || elements.isEmpty()) {
return empty();
} else {
final int size = size();
if (size <= elements.size()) {
return retainAll(elements);
} else {
final HashSet<T> results = HashSet.<T> ofAll(elements).retainAll(this);
return (size == results.size()) ? this : results;
}
}
}
/**
* A {@code HashSet} is computed synchronously.
*
* @return false
*/
@Override
public boolean isAsync() {
return false;
}
@Override
public boolean isEmpty() {
return tree.isEmpty();
}
/**
* A {@code HashSet} is computed eagerly.
*
* @return false
*/
@Override
public boolean isLazy() {
return false;
}
@Override
public boolean isTraversableAgain() {
return true;
}
@Override
public Iterator<T> iterator() {
return tree.keysIterator();
}
@Override
public int length() {
return tree.size();
}
@Override
public <U> HashSet<U> map(Function<? super T, ? extends U> mapper) {
Objects.requireNonNull(mapper, "mapper is null");
if (isEmpty()) {
return empty();
} else {
final HashArrayMappedTrie<U, U> that = foldLeft(HashArrayMappedTrie.empty(), (tree, t) -> {
final U u = mapper.apply(t);
return tree.put(u, u);
});
return new HashSet<>(that);
}
}
@Override
public String mkString(CharSequence prefix, CharSequence delimiter, CharSequence suffix) {
return iterator().mkString(prefix, delimiter, suffix);
}
@Override
public HashSet<T> orElse(Iterable<? extends T> other) {
return isEmpty() ? ofAll(other) : this;
}
@Override
public HashSet<T> orElse(Supplier<? extends Iterable<? extends T>> supplier) {
return isEmpty() ? ofAll(supplier.get()) : this;
}
@Override
public Tuple2<HashSet<T>, HashSet<T>> partition(Predicate<? super T> predicate) {
Objects.requireNonNull(predicate, "predicate is null");
final Tuple2<Iterator<T>, Iterator<T>> p = iterator().partition(predicate);
return Tuple.of(HashSet.ofAll(p._1), HashSet.ofAll(p._2));
}
@Override
public HashSet<T> peek(Consumer<? super T> action) {
Objects.requireNonNull(action, "action is null");
if (!isEmpty()) {
action.accept(iterator().head());
}
return this;
}
@Override
public HashSet<T> remove(T element) {
final HashArrayMappedTrie<T, T> newTree = tree.remove(element);
return (newTree == tree) ? this : new HashSet<>(newTree);
}
@Override
public HashSet<T> removeAll(Iterable<? extends T> elements) {
return Collections.removeAll(this, elements);
}
@Override
public HashSet<T> replace(T currentElement, T newElement) {
if (tree.containsKey(currentElement)) {
return remove(currentElement).add(newElement);
} else {
return this;
}
}
@Override
public HashSet<T> replaceAll(T currentElement, T newElement) {
return replace(currentElement, newElement);
}
@Override
public HashSet<T> retainAll(Iterable<? extends T> elements) {
return Collections.retainAll(this, elements);
}
@Override
public HashSet<T> scan(T zero, BiFunction<? super T, ? super T, ? extends T> operation) {
return scanLeft(zero, operation);
}
@Override
public <U> HashSet<U> scanLeft(U zero, BiFunction<? super U, ? super T, ? extends U> operation) {
return Collections.scanLeft(this, zero, operation, HashSet::ofAll);
}
@Override
public <U> HashSet<U> scanRight(U zero, BiFunction<? super T, ? super U, ? extends U> operation) {
return Collections.scanRight(this, zero, operation, HashSet::ofAll);
}
@Override
public Iterator<HashSet<T>> slideBy(Function<? super T, ?> classifier) {
return iterator().slideBy(classifier).map(HashSet::ofAll);
}
@Override
public Iterator<HashSet<T>> sliding(int size) {
return sliding(size, 1);
}
@Override
public Iterator<HashSet<T>> sliding(int size, int step) {
return iterator().sliding(size, step).map(HashSet::ofAll);
}
@Override
public Tuple2<HashSet<T>, HashSet<T>> span(Predicate<? super T> predicate) {
Objects.requireNonNull(predicate, "predicate is null");
final Tuple2<Iterator<T>, Iterator<T>> t = iterator().span(predicate);
return Tuple.of(HashSet.ofAll(t._1), HashSet.ofAll(t._2));
}
@Override
public HashSet<T> tail() {
if (tree.isEmpty()) {
throw new UnsupportedOperationException("tail of empty set");
}
return remove(head());
}
@Override
public Option<HashSet<T>> tailOption() {
if (tree.isEmpty()) {
return Option.none();
} else {
return Option.some(tail());
}
}
@Override
public HashSet<T> take(int n) {
if (n >= size() || isEmpty()) {
return this;
} else if (n <= 0) {
return empty();
} else {
return ofAll(() -> iterator().take(n));
}
}
@Override
public HashSet<T> takeRight(int n) {
return take(n);
}
@Override
public HashSet<T> takeUntil(Predicate<? super T> predicate) {
Objects.requireNonNull(predicate, "predicate is null");
return takeWhile(predicate.negate());
}
@Override
public HashSet<T> takeWhile(Predicate<? super T> predicate) {
Objects.requireNonNull(predicate, "predicate is null");
final HashSet<T> taken = HashSet.ofAll(iterator().takeWhile(predicate));
return taken.length() == length() ? this : taken;
}
/**
* Transforms this {@code HashSet}.
*
* @param f A transformation
* @param <U> Type of transformation result
* @return An instance of type {@code U}
* @throws NullPointerException if {@code f} is null
*/
public <U> U transform(Function<? super HashSet<T>, ? extends U> f) {
Objects.requireNonNull(f, "f is null");
return f.apply(this);
}
@Override
public java.util.HashSet<T> toJavaSet() {
return toJavaSet(java.util.HashSet::new);
}
@SuppressWarnings("unchecked")
@Override
public HashSet<T> union(Set<? extends T> elements) {
Objects.requireNonNull(elements, "elements is null");
if (isEmpty()) {
if (elements instanceof HashSet) {
return (HashSet<T>) elements;
} else {
return HashSet.ofAll(elements);
}
} else if (elements.isEmpty()) {
return this;
} else {
final HashArrayMappedTrie<T, T> that = addAll(tree, elements);
if (that.size() == tree.size()) {
return this;
} else {
return new HashSet<>(that);
}
}
}
@Override
public <T1, T2> Tuple2<HashSet<T1>, HashSet<T2>> unzip(
Function<? super T, Tuple2<? extends T1, ? extends T2>> unzipper) {
Objects.requireNonNull(unzipper, "unzipper is null");
final Tuple2<Iterator<T1>, Iterator<T2>> t = iterator().unzip(unzipper);
return Tuple.of(HashSet.ofAll(t._1), HashSet.ofAll(t._2));
}
@Override
public <T1, T2, T3> Tuple3<HashSet<T1>, HashSet<T2>, HashSet<T3>> unzip3(
Function<? super T, Tuple3<? extends T1, ? extends T2, ? extends T3>> unzipper) {
Objects.requireNonNull(unzipper, "unzipper is null");
final Tuple3<Iterator<T1>, Iterator<T2>, Iterator<T3>> t = iterator().unzip3(unzipper);
return Tuple.of(HashSet.ofAll(t._1), HashSet.ofAll(t._2), HashSet.ofAll(t._3));
}
@Override
public <U> HashSet<Tuple2<T, U>> zip(Iterable<? extends U> that) {
return zipWith(that, Tuple::of);
}
@Override
public <U, R> HashSet<R> zipWith(Iterable<? extends U> that, BiFunction<? super T, ? super U, ? extends R> mapper) {
Objects.requireNonNull(that, "that is null");
Objects.requireNonNull(mapper, "mapper is null");
return HashSet.ofAll(iterator().zipWith(that, mapper));
}
@Override
public <U> HashSet<Tuple2<T, U>> zipAll(Iterable<? extends U> that, T thisElem, U thatElem) {
Objects.requireNonNull(that, "that is null");
return HashSet.ofAll(iterator().zipAll(that, thisElem, thatElem));
}
@Override
public HashSet<Tuple2<T, Integer>> zipWithIndex() {
return zipWithIndex(Tuple::of);
}
@Override
public <U> HashSet<U> zipWithIndex(BiFunction<? super T, ? super Integer, ? extends U> mapper) {
Objects.requireNonNull(mapper, "mapper is null");
return HashSet.ofAll(iterator().zipWithIndex(mapper));
}
// -- Object
@Override
public boolean equals(Object o) {
return Collections.equals(this, o);
}
@Override
public int hashCode() {
return Collections.hashUnordered(this);
}
@Override
public String stringPrefix() {
return "HashSet";
}
@Override
public String toString() {
return mkString(stringPrefix() + "(", ", ", ")");
}
private static <T> HashArrayMappedTrie<T, T> addAll(HashArrayMappedTrie<T, T> initial,
Iterable<? extends T> additional) {
HashArrayMappedTrie<T, T> that = initial;
for (T t : additional) {
that = that.put(t, t);
}
return that;
}
// -- Serialization
/**
* {@code writeReplace} method for the serialization proxy pattern.
* <p>
* The presence of this method causes the serialization system to emit a SerializationProxy instance instead of
* an instance of the enclosing class.
*
* @return A SerializationProxy for this enclosing class.
*/
@GwtIncompatible("The Java serialization protocol is explicitly not supported")
private Object writeReplace() {
return new SerializationProxy<>(this.tree);
}
/**
* {@code readObject} method for the serialization proxy pattern.
* <p>
* Guarantees that the serialization system will never generate a serialized instance of the enclosing class.
*
* @param stream An object serialization stream.
* @throws java.io.InvalidObjectException This method will throw with the message "Proxy required".
*/
@GwtIncompatible("The Java serialization protocol is explicitly not supported")
private void readObject(ObjectInputStream stream) throws InvalidObjectException {
throw new InvalidObjectException("Proxy required");
}
/**
* A serialization proxy which, in this context, is used to deserialize immutable, linked Lists with final
* instance fields.
*
* @param <T> The component type of the underlying list.
*/
// DEV NOTE: The serialization proxy pattern is not compatible with non-final, i.e. extendable,
// classes. Also, it may not be compatible with circular object graphs.
@GwtIncompatible("The Java serialization protocol is explicitly not supported")
private static final class SerializationProxy<T> implements Serializable {
private static final long serialVersionUID = 1L;
// the instance to be serialized/deserialized
private transient HashArrayMappedTrie<T, T> tree;
/**
* Constructor for the case of serialization, called by {@link HashSet#writeReplace()}.
* <p/>
* The constructor of a SerializationProxy takes an argument that concisely represents the logical state of
* an instance of the enclosing class.
*
* @param tree a Cons
*/
SerializationProxy(HashArrayMappedTrie<T, T> tree) {
this.tree = tree;
}
/**
* Write an object to a serialization stream.
*
* @param s An object serialization stream.
* @throws java.io.IOException If an error occurs writing to the stream.
*/
private void writeObject(ObjectOutputStream s) throws IOException {
s.defaultWriteObject();
s.writeInt(tree.size());
for (Tuple2<T, T> e : tree) {
s.writeObject(e._1);
}
}
/**
* Read an object from a deserialization stream.
*
* @param s An object deserialization stream.
* @throws ClassNotFoundException If the object's class read from the stream cannot be found.
* @throws InvalidObjectException If the stream contains no list elements.
* @throws IOException If an error occurs reading from the stream.
*/
private void readObject(ObjectInputStream s) throws ClassNotFoundException, IOException {
s.defaultReadObject();
final int size = s.readInt();
if (size < 0) {
throw new InvalidObjectException("No elements");
}
HashArrayMappedTrie<T, T> temp = HashArrayMappedTrie.empty();
for (int i = 0; i < size; i++) {
@SuppressWarnings("unchecked")
final T element = (T) s.readObject();
temp = temp.put(element, element);
}
tree = temp;
}
/**
* {@code readResolve} method for the serialization proxy pattern.
* <p>
* Returns a logically equivalent instance of the enclosing class. The presence of this method causes the
* serialization system to translate the serialization proxy back into an instance of the enclosing class
* upon deserialization.
*
* @return A deserialized instance of the enclosing class.
*/
private Object readResolve() {
return tree.isEmpty() ? HashSet.empty() : new HashSet<>(tree);
}
}
}