/* __ __ __ __ __ ___
* \ \ / / \ \ / / __/
* \ \/ / /\ \ \/ / /
* \____/__/ \__\____/__/.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.util.*;
import java.util.function.*;
import java.util.stream.Collector;
import static io.vavr.collection.JavaConverters.ChangePolicy.IMMUTABLE;
import static io.vavr.collection.JavaConverters.ChangePolicy.MUTABLE;
/**
* An immutable {@code Queue} stores elements allowing a first-in-first-out (FIFO) retrieval.
* <p>
* Queue API:
*
* <ul>
* <li>{@link #dequeue()}</li>
* <li>{@link #dequeueOption()}</li>
* <li>{@link #enqueue(Object)}</li>
* <li>{@link #enqueue(Object[])}</li>
* <li>{@link #enqueueAll(Iterable)}</li>
* <li>{@link #peek()}</li>
* <li>{@link #peekOption()}</li>
* </ul>
*
* A Queue internally consists of a front List containing the front elements of the Queue in the correct order and a
* rear List containing the rear elements of the Queue in reverse order.
* <p>
* When the front list is empty, front and rear are swapped and rear is reversed. This implies the following queue
* invariant: {@code front.isEmpty() => rear.isEmpty()}.
* <p>
* See Okasaki, Chris: <em>Purely Functional Data Structures</em> (p. 42 ff.). Cambridge, 2003.
*
* @param <T> Component type of the Queue
* @author Daniel Dietrich
*/
public final class Queue<T> extends AbstractQueue<T, Queue<T>> implements LinearSeq<T> {
private static final long serialVersionUID = 1L;
private static final Queue<?> EMPTY = new Queue<>(io.vavr.collection.List.empty(), io.vavr.collection.List.empty());
private final io.vavr.collection.List<T> front;
private final io.vavr.collection.List<T> rear;
/**
* Creates a Queue consisting of a front List and a rear List.
* <p>
* For a {@code Queue(front, rear)} the following invariant holds: {@code Queue is empty <=> front is empty}.
* In other words: If the Queue is not empty, the front List contains at least one element.
*
* @param front A List of front elements, in correct order.
* @param rear A List of rear elements, in reverse order.
*/
private Queue(io.vavr.collection.List<T> front, io.vavr.collection.List<T> rear) {
final boolean frontIsEmpty = front.isEmpty();
this.front = frontIsEmpty ? rear.reverse() : front;
this.rear = frontIsEmpty ? front : rear;
}
/**
* 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 Queue}
* .
*
* @param <T> Component type of the Queue.
* @return A io.vavr.collection.Queue Collector.
*/
public static <T> Collector<T, ArrayList<T>, Queue<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>, Queue<T>> finisher = Queue::ofAll;
return Collector.of(supplier, accumulator, combiner, finisher);
}
/**
* Returns the empty Queue.
*
* @param <T> Component type
* @return The empty Queue.
*/
@SuppressWarnings("unchecked")
public static <T> Queue<T> empty() {
return (Queue<T>) EMPTY;
}
/**
* Narrows a widened {@code Queue<? extends T>} to {@code Queue<T>}
* by performing a type-safe cast. This is eligible because immutable/read-only
* collections are covariant.
*
* @param queue An {@code Queue}.
* @param <T> Component type of the {@code Queue}.
* @return the given {@code queue} instance as narrowed type {@code Queue<T>}.
*/
@SuppressWarnings("unchecked")
public static <T> Queue<T> narrow(Queue<? extends T> queue) {
return (Queue<T>) queue;
}
/**
* Returns a singleton {@code Queue}, i.e. a {@code Queue} of one element.
*
* @param element An element.
* @param <T> The component type
* @return A new Queue instance containing the given element
*/
public static <T> Queue<T> of(T element) {
return ofAll(io.vavr.collection.List.of(element));
}
/**
* Creates a Queue of the given elements.
*
* @param <T> Component type of the Queue.
* @param elements Zero or more elements.
* @return A queue containing the given elements in the same order.
* @throws NullPointerException if {@code elements} is null
*/
@SuppressWarnings("varargs")
@SafeVarargs
public static <T> Queue<T> of(T... elements) {
Objects.requireNonNull(elements, "elements is null");
return ofAll(io.vavr.collection.List.of(elements));
}
/**
* Creates a Queue of the given elements.
*
* @param <T> Component type of the Queue.
* @param elements An Iterable of elements.
* @return A queue containing the given elements in the same order.
* @throws NullPointerException if {@code elements} is null
*/
@SuppressWarnings("unchecked")
public static <T> Queue<T> ofAll(Iterable<? extends T> elements) {
Objects.requireNonNull(elements, "elements is null");
if (elements instanceof Queue) {
return (Queue<T>) elements;
} else if (!elements.iterator().hasNext()) {
return empty();
} else if (elements instanceof io.vavr.collection.List) {
return new Queue<>((io.vavr.collection.List<T>) elements, io.vavr.collection.List.empty());
} else {
return new Queue<>(io.vavr.collection.List.ofAll(elements), io.vavr.collection.List.empty());
}
}
/**
* Creates a Queue 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 Queue containing the given elements in the same order.
*/
public static <T> Queue<T> ofAll(java.util.stream.Stream<? extends T> javaStream) {
Objects.requireNonNull(javaStream, "javaStream is null");
return new Queue<>(io.vavr.collection.List.ofAll(javaStream), io.vavr.collection.List.empty());
}
/**
* Creates a Queue from boolean values.
*
* @param elements boolean values
* @return A new Queue of Boolean values
* @throws NullPointerException if elements is null
*/
public static Queue<Boolean> ofAll(boolean... elements) {
Objects.requireNonNull(elements, "elements is null");
return ofAll(io.vavr.collection.List.ofAll(elements));
}
/**
* Creates a Queue from byte values.
*
* @param elements byte values
* @return A new Queue of Byte values
* @throws NullPointerException if elements is null
*/
public static Queue<Byte> ofAll(byte... elements) {
Objects.requireNonNull(elements, "elements is null");
return ofAll(io.vavr.collection.List.ofAll(elements));
}
/**
* Creates a Queue from char values.
*
* @param elements char values
* @return A new Queue of Character values
* @throws NullPointerException if elements is null
*/
public static Queue<Character> ofAll(char... elements) {
Objects.requireNonNull(elements, "elements is null");
return ofAll(io.vavr.collection.List.ofAll(elements));
}
/**
* Creates a Queue from double values.
*
* @param elements double values
* @return A new Queue of Double values
* @throws NullPointerException if elements is null
*/
public static Queue<Double> ofAll(double... elements) {
Objects.requireNonNull(elements, "elements is null");
return ofAll(io.vavr.collection.List.ofAll(elements));
}
/**
* Creates a Queue from float values.
*
* @param elements float values
* @return A new Queue of Float values
* @throws NullPointerException if elements is null
*/
public static Queue<Float> ofAll(float... elements) {
Objects.requireNonNull(elements, "elements is null");
return ofAll(io.vavr.collection.List.ofAll(elements));
}
/**
* Creates a Queue from int values.
*
* @param elements int values
* @return A new Queue of Integer values
* @throws NullPointerException if elements is null
*/
public static Queue<Integer> ofAll(int... elements) {
Objects.requireNonNull(elements, "elements is null");
return ofAll(io.vavr.collection.List.ofAll(elements));
}
/**
* Creates a Queue from long values.
*
* @param elements long values
* @return A new Queue of Long values
* @throws NullPointerException if elements is null
*/
public static Queue<Long> ofAll(long... elements) {
Objects.requireNonNull(elements, "elements is null");
return ofAll(io.vavr.collection.List.ofAll(elements));
}
/**
* Creates a Queue from short values.
*
* @param elements short values
* @return A new Queue of Short values
* @throws NullPointerException if elements is null
*/
public static Queue<Short> ofAll(short... elements) {
Objects.requireNonNull(elements, "elements is null");
return ofAll(io.vavr.collection.List.ofAll(elements));
}
/**
* Returns a Queue 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 Queue
* @param n The number of elements in the Queue
* @param f The Function computing element values
* @return A Queue consisting of elements {@code f(0),f(1), ..., f(n - 1)}
* @throws NullPointerException if {@code f} is null
*/
public static <T> Queue<T> tabulate(int n, Function<? super Integer, ? extends T> f) {
Objects.requireNonNull(f, "f is null");
return io.vavr.collection.Collections.tabulate(n, f, empty(), Queue::of);
}
/**
* Returns a Queue containing {@code n} values supplied by a given Supplier {@code s}.
*
* @param <T> Component type of the Queue
* @param n The number of elements in the Queue
* @param s The Supplier computing element values
* @return An Queue of size {@code n}, where each element contains the result supplied by {@code s}.
* @throws NullPointerException if {@code s} is null
*/
public static <T> Queue<T> fill(int n, Supplier<? extends T> s) {
Objects.requireNonNull(s, "s is null");
return io.vavr.collection.Collections.fill(n, s, empty(), Queue::of);
}
public static Queue<Character> range(char from, char toExclusive) {
return ofAll(Iterator.range(from, toExclusive));
}
public static Queue<Character> rangeBy(char from, char toExclusive, int step) {
return ofAll(Iterator.rangeBy(from, toExclusive, step));
}
@GwtIncompatible
public static Queue<Double> rangeBy(double from, double toExclusive, double step) {
return ofAll(Iterator.rangeBy(from, toExclusive, step));
}
/**
* Creates a Queue of int numbers starting from {@code from}, extending to {@code toExclusive - 1}.
* <p>
* Examples:
* <pre>
* <code>
* Queue.range(0, 0) // = Queue()
* Queue.range(2, 0) // = Queue()
* Queue.range(-2, 2) // = Queue(-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 {@code Nil} if {@code from >= toExclusive}
*/
public static Queue<Integer> range(int from, int toExclusive) {
return ofAll(Iterator.range(from, toExclusive));
}
/**
* Creates a Queue of int numbers starting from {@code from}, extending to {@code toExclusive - 1},
* with {@code step}.
* <p>
* Examples:
* <pre>
* <code>
* Queue.rangeBy(1, 3, 1) // = Queue(1, 2)
* Queue.rangeBy(1, 4, 2) // = Queue(1, 3)
* Queue.rangeBy(4, 1, -2) // = Queue(4, 2)
* Queue.rangeBy(4, 1, 2) // = Queue()
* </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 {@code Nil} 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 Queue<Integer> rangeBy(int from, int toExclusive, int step) {
return ofAll(Iterator.rangeBy(from, toExclusive, step));
}
/**
* Creates a Queue of long numbers starting from {@code from}, extending to {@code toExclusive - 1}.
* <p>
* Examples:
* <pre>
* <code>
* Queue.range(0L, 0L) // = Queue()
* Queue.range(2L, 0L) // = Queue()
* Queue.range(-2L, 2L) // = Queue(-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 {@code Nil} if {@code from >= toExclusive}
*/
public static Queue<Long> range(long from, long toExclusive) {
return ofAll(Iterator.range(from, toExclusive));
}
/**
* Creates a Queue of long numbers starting from {@code from}, extending to {@code toExclusive - 1},
* with {@code step}.
* <p>
* Examples:
* <pre>
* <code>
* Queue.rangeBy(1L, 3L, 1L) // = Queue(1L, 2L)
* Queue.rangeBy(1L, 4L, 2L) // = Queue(1L, 3L)
* Queue.rangeBy(4L, 1L, -2L) // = Queue(4L, 2L)
* Queue.rangeBy(4L, 1L, 2L) // = Queue()
* </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 {@code Nil} 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 Queue<Long> rangeBy(long from, long toExclusive, long step) {
return ofAll(Iterator.rangeBy(from, toExclusive, step));
}
public static Queue<Character> rangeClosed(char from, char toInclusive) {
return ofAll(Iterator.rangeClosed(from, toInclusive));
}
public static Queue<Character> rangeClosedBy(char from, char toInclusive, int step) {
return ofAll(Iterator.rangeClosedBy(from, toInclusive, step));
}
@GwtIncompatible
public static Queue<Double> rangeClosedBy(double from, double toInclusive, double step) {
return ofAll(Iterator.rangeClosedBy(from, toInclusive, step));
}
/**
* Creates a Queue of int numbers starting from {@code from}, extending to {@code toInclusive}.
* <p>
* Examples:
* <pre>
* <code>
* Queue.rangeClosed(0, 0) // = Queue(0)
* Queue.rangeClosed(2, 0) // = Queue()
* Queue.rangeClosed(-2, 2) // = Queue(-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 {@code Nil} if {@code from > toInclusive}
*/
public static Queue<Integer> rangeClosed(int from, int toInclusive) {
return ofAll(Iterator.rangeClosed(from, toInclusive));
}
/**
* Creates a Queue of int numbers starting from {@code from}, extending to {@code toInclusive},
* with {@code step}.
* <p>
* Examples:
* <pre>
* <code>
* Queue.rangeClosedBy(1, 3, 1) // = Queue(1, 2, 3)
* Queue.rangeClosedBy(1, 4, 2) // = Queue(1, 3)
* Queue.rangeClosedBy(4, 1, -2) // = Queue(4, 2)
* Queue.rangeClosedBy(4, 1, 2) // = Queue()
* </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 {@code Nil} 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 Queue<Integer> rangeClosedBy(int from, int toInclusive, int step) {
return ofAll(Iterator.rangeClosedBy(from, toInclusive, step));
}
/**
* Creates a Queue of long numbers starting from {@code from}, extending to {@code toInclusive}.
* <p>
* Examples:
* <pre>
* <code>
* Queue.rangeClosed(0L, 0L) // = Queue(0L)
* Queue.rangeClosed(2L, 0L) // = Queue()
* Queue.rangeClosed(-2L, 2L) // = Queue(-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 {@code Nil} if {@code from > toInclusive}
*/
public static Queue<Long> rangeClosed(long from, long toInclusive) {
return ofAll(Iterator.rangeClosed(from, toInclusive));
}
/**
* Transposes the rows and columns of a {@link Queue} matrix.
*
* @param <T> matrix element type
* @param matrix to be transposed.
* @return a transposed {@link Queue} matrix.
* @throws IllegalArgumentException if the row lengths of {@code matrix} differ.
*
* <p>
* ex: {@code
* Queue.transpose(Queue(Queue(1,2,3), Queue(4,5,6))) → Queue(Queue(1,4), Queue(2,5), Queue(3,6))
* }
*/
public static <T> Queue<Queue<T>> transpose(Queue<Queue<T>> matrix) {
return io.vavr.collection.Collections.transpose(matrix, Queue::ofAll, Queue::of);
}
/**
* Creates a Queue of long numbers starting from {@code from}, extending to {@code toInclusive},
* with {@code step}.
* <p>
* Examples:
* <pre>
* <code>
* Queue.rangeClosedBy(1L, 3L, 1L) // = Queue(1L, 2L, 3L)
* Queue.rangeClosedBy(1L, 4L, 2L) // = Queue(1L, 3L)
* Queue.rangeClosedBy(4L, 1L, -2L) // = Queue(4L, 2L)
* Queue.rangeClosedBy(4L, 1L, 2L) // = Queue()
* </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 {@code Nil} 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 Queue<Long> rangeClosedBy(long from, long toInclusive, long step) {
return ofAll(Iterator.rangeClosedBy(from, toInclusive, step));
}
/**
* Creates a Queue from a seed value and a function.
* The function takes the seed at first.
* The function should return {@code None} when it's
* done generating the Queue, otherwise {@code Some} {@code Tuple}
* of the element for the next call and the value to add to the
* resulting Queue.
* <p>
* Example:
* <pre>
* <code>
* Queue.unfoldRight(10, x -> x == 0
* ? Option.none()
* : Option.of(new Tuple2<>(x, x-1)));
* // Queue(10, 9, 8, 7, 6, 5, 4, 3, 2, 1))
* </code>
* </pre>
*
* @param <T> type of seeds
* @param <U> type of unfolded values
* @param seed the start value for the iteration
* @param f the function to get the next step of the iteration
* @return a Queue with the values built up by the iteration
* @throws NullPointerException if {@code f} is null
*/
public static <T, U> Queue<U> unfoldRight(T seed, Function<? super T, Option<Tuple2<? extends U, ? extends T>>> f) {
return Iterator.unfoldRight(seed, f).toQueue();
}
/**
* Creates a Queue from a seed value and a function.
* The function takes the seed at first.
* The function should return {@code None} when it's
* done generating the Queue, otherwise {@code Some} {@code Tuple}
* of the value to add to the resulting Queue and
* the element for the next call.
* <p>
* Example:
* <pre>
* <code>
* Queue.unfoldLeft(10, x -> x == 0
* ? Option.none()
* : Option.of(new Tuple2<>(x-1, x)));
* // Queue(1, 2, 3, 4, 5, 6, 7, 8, 9, 10))
* </code>
* </pre>
*
* @param <T> type of seeds
* @param <U> type of unfolded values
* @param seed the start value for the iteration
* @param f the function to get the next step of the iteration
* @return a Queue with the values built up by the iteration
* @throws NullPointerException if {@code f} is null
*/
public static <T, U> Queue<U> unfoldLeft(T seed, Function<? super T, Option<Tuple2<? extends T, ? extends U>>> f) {
return Iterator.unfoldLeft(seed, f).toQueue();
}
/**
* Creates a Queue from a seed value and a function.
* The function takes the seed at first.
* The function should return {@code None} when it's
* done generating the Queue, otherwise {@code Some} {@code Tuple}
* of the value to add to the resulting Queue and
* the element for the next call.
* <p>
* Example:
* <pre>
* <code>
* Queue.unfold(10, x -> x == 0
* ? Option.none()
* : Option.of(new Tuple2<>(x-1, x)));
* // Queue(1, 2, 3, 4, 5, 6, 7, 8, 9, 10))
* </code>
* </pre>
*
* @param <T> type of seeds and unfolded values
* @param seed the start value for the iteration
* @param f the function to get the next step of the iteration
* @return a Queue with the values built up by the iteration
* @throws NullPointerException if {@code f} is null
*/
public static <T> Queue<T> unfold(T seed, Function<? super T, Option<Tuple2<? extends T, ? extends T>>> f) {
return Iterator.unfold(seed, f).toQueue();
}
/**
* Enqueues a new element.
*
* @param element The new element
* @return a new {@code Queue} instance, containing the new element
*/
@Override
public Queue<T> enqueue(T element) {
return new Queue<>(front, rear.prepend(element));
}
/**
* Enqueues the given elements. A queue has FIFO order, i.e. the first of the given elements is
* the first which will be retrieved.
*
* @param elements An Iterable of elements, may be empty
* @return a new {@code Queue} instance, containing the new elements
* @throws NullPointerException if elements is null
*/
@SuppressWarnings("unchecked")
public Queue<T> enqueueAll(Iterable<? extends T> elements) {
Objects.requireNonNull(elements, "elements is null");
if (isEmpty() && elements instanceof Queue) {
return (Queue<T>) elements;
} else {
return io.vavr.collection.List.ofAll(elements).foldLeft(this, Queue::enqueue);
}
}
// -- Adjusted return types of Seq methods
@Override
public Queue<T> append(T element) {
return enqueue(element);
}
@Override
public Queue<T> appendAll(Iterable<? extends T> elements) {
return enqueueAll(elements);
}
@GwtIncompatible
@Override
public java.util.List<T> asJava() {
return JavaConverters.asJava(this, IMMUTABLE);
}
@GwtIncompatible
@Override
public Queue<T> asJava(Consumer<? super java.util.List<T>> action) {
return Collections.asJava(this, action, IMMUTABLE);
}
@GwtIncompatible
@Override
public java.util.List<T> asJavaMutable() {
return JavaConverters.asJava(this, MUTABLE);
}
@GwtIncompatible
@Override
public Queue<T> asJavaMutable(Consumer<? super java.util.List<T>> action) {
return Collections.asJava(this, action, MUTABLE);
}
@Override
public <R> Queue<R> collect(PartialFunction<? super T, ? extends R> partialFunction) {
return ofAll(iterator().<R> collect(partialFunction));
}
@Override
public Queue<Queue<T>> combinations() {
return ofAll(toList().combinations().map(Queue::ofAll));
}
@Override
public Queue<Queue<T>> combinations(int k) {
return ofAll(toList().combinations(k).map(Queue::ofAll));
}
@Override
public Iterator<Queue<T>> crossProduct(int power) {
return io.vavr.collection.Collections.crossProduct(empty(), this, power);
}
@Override
public Queue<T> distinct() {
return ofAll(toList().distinct());
}
@Override
public Queue<T> distinctBy(Comparator<? super T> comparator) {
Objects.requireNonNull(comparator, "comparator is null");
return ofAll(toList().distinctBy(comparator));
}
@Override
public <U> Queue<T> distinctBy(Function<? super T, ? extends U> keyExtractor) {
Objects.requireNonNull(keyExtractor, "keyExtractor is null");
return ofAll(toList().distinctBy(keyExtractor));
}
@Override
public Queue<T> drop(int n) {
if (n <= 0) {
return this;
}
if (n >= length()) {
return empty();
}
return new Queue<>(front.drop(n), rear.dropRight(n - front.length()));
}
@Override
public Queue<T> dropUntil(Predicate<? super T> predicate) {
return io.vavr.collection.Collections.dropUntil(this, predicate);
}
@Override
public Queue<T> dropWhile(Predicate<? super T> predicate) {
Objects.requireNonNull(predicate, "predicate is null");
return dropUntil(predicate.negate());
}
@Override
public Queue<T> dropRight(int n) {
if (n <= 0) {
return this;
}
if (n >= length()) {
return empty();
}
return new Queue<>(front.dropRight(n - rear.length()), rear.drop(n));
}
@Override
public Queue<T> dropRightUntil(Predicate<? super T> predicate) {
return io.vavr.collection.Collections.dropUntil(reverse(), predicate).reverse();
}
@Override
public Queue<T> dropRightWhile(Predicate<? super T> predicate) {
Objects.requireNonNull(predicate, "predicate is null");
return dropRightUntil(predicate.negate());
}
@Override
public Queue<T> filter(Predicate<? super T> predicate) {
Objects.requireNonNull(predicate, "predicate is null");
final io.vavr.collection.List<T> filtered = toList().filter(predicate);
if (filtered.isEmpty()) {
return empty();
} else if (filtered.length() == length()) {
return this;
} else {
return ofAll(filtered);
}
}
@Override
public <U> Queue<U> flatMap(Function<? super T, ? extends Iterable<? extends U>> mapper) {
Objects.requireNonNull(mapper, "mapper is null");
if (isEmpty()) {
return empty();
} else {
return new Queue<>(front.flatMap(mapper), rear.flatMap(mapper));
}
}
@Override
public T get(int index) {
if (isEmpty()) {
throw new IndexOutOfBoundsException("get(" + index + ") on empty Queue");
}
if (index < 0) {
throw new IndexOutOfBoundsException("get(" + index + ")");
}
final int length = front.length();
if (index < length) {
return front.get(index);
} else {
final int rearIndex = index - length;
final int rearLength = rear.length();
if (rearIndex < rearLength) {
final int reverseRearIndex = rearLength - rearIndex - 1;
return rear.get(reverseRearIndex);
} else {
throw new IndexOutOfBoundsException("get(" + index + ") on Queue of length " + length());
}
}
}
@Override
public <C> Map<C, Queue<T>> groupBy(Function<? super T, ? extends C> classifier) {
return io.vavr.collection.Collections.groupBy(this, classifier, Queue::ofAll);
}
@Override
public Iterator<Queue<T>> grouped(int size) {
return sliding(size, size);
}
@Override
public boolean hasDefiniteSize() {
return true;
}
@Override
public T head() {
if (isEmpty()) {
throw new NoSuchElementException("head of empty " + stringPrefix());
} else {
return front.head();
}
}
@Override
public int indexOf(T element, int from) {
final int frontIndex = front.indexOf(element, from);
if (frontIndex != -1) {
return frontIndex;
} else {
// we need to reverse because we search the first occurrence
final int rearIndex = rear.reverse().indexOf(element, from - front.length());
return (rearIndex == -1) ? -1 : rearIndex + front.length();
}
}
@Override
public Queue<T> init() {
if (isEmpty()) {
throw new UnsupportedOperationException("init of empty " + stringPrefix());
} else if (rear.isEmpty()) {
return new Queue<>(front.init(), rear);
} else {
return new Queue<>(front, rear.tail());
}
}
@Override
public Queue<T> insert(int index, T element) {
if (index < 0) {
throw new IndexOutOfBoundsException("insert(" + index + ", element)");
}
final int length = front.length();
if (index <= length) {
return new Queue<>(front.insert(index, element), rear);
} else {
final int rearIndex = index - length;
final int rearLength = rear.length();
if (rearIndex <= rearLength) {
final int reverseRearIndex = rearLength - rearIndex;
return new Queue<>(front, rear.insert(reverseRearIndex, element));
} else {
throw new IndexOutOfBoundsException("insert(" + index + ", element) on Queue of length " + length());
}
}
}
@SuppressWarnings("unchecked")
@Override
public Queue<T> insertAll(int index, Iterable<? extends T> elements) {
Objects.requireNonNull(elements, "elements is null");
if (index < 0) {
throw new IndexOutOfBoundsException("insertAll(" + index + ", elements)");
}
final int length = front.length();
if (index <= length) {
if (isEmpty() && elements instanceof Queue) {
return (Queue<T>) elements;
} else {
final io.vavr.collection.List<T> newFront = front.insertAll(index, elements);
return (newFront == front) ? this : new Queue<>(newFront, rear);
}
} else {
final int rearIndex = index - length;
final int rearLength = rear.length();
if (rearIndex <= rearLength) {
final int reverseRearIndex = rearLength - rearIndex;
final io.vavr.collection.List<T> newRear = rear.insertAll(reverseRearIndex, io.vavr.collection.List.ofAll(elements).reverse());
return (newRear == rear) ? this : new Queue<>(front, newRear);
} else {
throw new IndexOutOfBoundsException("insertAll(" + index + ", elements) on Queue of length " + length());
}
}
}
@Override
public Queue<T> intersperse(T element) {
if (isEmpty()) {
return this;
} else if (rear.isEmpty()) {
return new Queue<>(front.intersperse(element), rear);
} else {
return new Queue<>(front.intersperse(element), rear.intersperse(element).append(element));
}
}
/**
* A {@code Queue} is computed synchronously.
*
* @return false
*/
@Override
public boolean isAsync() {
return false;
}
@Override
public boolean isEmpty() {
return front.isEmpty();
}
/**
* A {@code Queue} is computed eagerly.
*
* @return false
*/
@Override
public boolean isLazy() {
return false;
}
@Override
public boolean isTraversableAgain() {
return true;
}
@Override
public int lastIndexOf(T element, int end) {
return toList().lastIndexOf(element, end);
}
@Override
public int length() {
return front.length() + rear.length();
}
@Override
public <U> Queue<U> map(Function<? super T, ? extends U> mapper) {
Objects.requireNonNull(mapper, "mapper is null");
return new Queue<>(front.map(mapper), rear.map(mapper));
}
@Override
public Queue<T> orElse(Iterable<? extends T> other) {
return isEmpty() ? ofAll(other) : this;
}
@Override
public Queue<T> orElse(Supplier<? extends Iterable<? extends T>> supplier) {
return isEmpty() ? ofAll(supplier.get()) : this;
}
@Override
public Queue<T> padTo(int length, T element) {
final int actualLength = length();
if (length <= actualLength) {
return this;
} else {
return ofAll(toList().padTo(length, element));
}
}
@Override
public Queue<T> leftPadTo(int length, T element) {
final int actualLength = length();
if (length <= actualLength) {
return this;
} else {
return ofAll(toList().leftPadTo(length, element));
}
}
@Override
public Queue<T> patch(int from, Iterable<? extends T> that, int replaced) {
from = from < 0 ? 0 : from;
replaced = replaced < 0 ? 0 : replaced;
Queue<T> result = take(from).appendAll(that);
from += replaced;
result = result.appendAll(drop(from));
return result;
}
@Override
public Tuple2<Queue<T>, Queue<T>> partition(Predicate<? super T> predicate) {
Objects.requireNonNull(predicate, "predicate is null");
return toList().partition(predicate).map(io.vavr.collection.List::toQueue, io.vavr.collection.List::toQueue);
}
@Override
public Queue<Queue<T>> permutations() {
return ofAll(toList().permutations().map(io.vavr.collection.List::toQueue));
}
@Override
public Queue<T> prepend(T element) {
return new Queue<>(front.prepend(element), rear);
}
@SuppressWarnings("unchecked")
@Override
public Queue<T> prependAll(Iterable<? extends T> elements) {
Objects.requireNonNull(elements, "elements is null");
if (isEmpty() && elements instanceof Queue) {
return (Queue<T>) elements;
} else {
final io.vavr.collection.List<T> newFront = front.prependAll(elements);
return (newFront == front) ? this : new Queue<>(newFront, rear);
}
}
@Override
public Queue<T> remove(T element) {
final io.vavr.collection.List<T> removed = toList().remove(element);
return ofAll(removed.length() == length() ? this : removed);
}
@Override
public Queue<T> removeFirst(Predicate<T> predicate) {
final io.vavr.collection.List<T> removed = toList().removeFirst(predicate);
return ofAll(removed.length() == length() ? this : removed);
}
@Override
public Queue<T> removeLast(Predicate<T> predicate) {
final io.vavr.collection.List<T> removed = toList().removeLast(predicate);
return ofAll(removed.length() == length() ? this : removed);
}
@Override
public Queue<T> removeAt(int index) {
return ofAll(toList().removeAt(index));
}
@Override
public Queue<T> removeAll(T element) {
return io.vavr.collection.Collections.removeAll(this, element);
}
@Override
public Queue<T> replace(T currentElement, T newElement) {
final io.vavr.collection.List<T> newFront = front.replace(currentElement, newElement);
final io.vavr.collection.List<T> newRear = rear.replace(currentElement, newElement);
return newFront.size() + newRear.size() == 0 ? empty()
: newFront == front && newRear == rear ? this
: new Queue<>(newFront, newRear);
}
@Override
public Queue<T> replaceAll(T currentElement, T newElement) {
final io.vavr.collection.List<T> newFront = front.replaceAll(currentElement, newElement);
final io.vavr.collection.List<T> newRear = rear.replaceAll(currentElement, newElement);
return newFront.size() + newRear.size() == 0 ? empty()
: newFront == front && newRear == rear ? this
: new Queue<>(newFront, newRear);
}
@Override
public Queue<T> reverse() {
return isEmpty() ? this : ofAll(toList().reverse());
}
@Override
public Queue<T> scan(T zero, BiFunction<? super T, ? super T, ? extends T> operation) {
return scanLeft(zero, operation);
}
@Override
public <U> Queue<U> scanLeft(U zero, BiFunction<? super U, ? super T, ? extends U> operation) {
return io.vavr.collection.Collections.scanLeft(this, zero, operation, Iterator::toQueue);
}
@Override
public <U> Queue<U> scanRight(U zero, BiFunction<? super T, ? super U, ? extends U> operation) {
return io.vavr.collection.Collections.scanRight(this, zero, operation, Iterator::toQueue);
}
@Override
public Queue<T> shuffle() {
return io.vavr.collection.Collections.shuffle(this, Queue::ofAll);
}
@Override
public Queue<T> slice(int beginIndex, int endIndex) {
return ofAll(toList().slice(beginIndex, endIndex));
}
@Override
public Iterator<Queue<T>> slideBy(Function<? super T, ?> classifier) {
return iterator().slideBy(classifier).map(Queue::ofAll);
}
@Override
public Iterator<Queue<T>> sliding(int size) {
return sliding(size, 1);
}
@Override
public Iterator<Queue<T>> sliding(int size, int step) {
return iterator().sliding(size, step).map(Queue::ofAll);
}
@Override
public Queue<T> sorted() {
return ofAll(toList().sorted());
}
@Override
public Queue<T> sorted(Comparator<? super T> comparator) {
Objects.requireNonNull(comparator, "comparator is null");
return ofAll(toList().sorted(comparator));
}
@Override
public <U extends Comparable<? super U>> Queue<T> sortBy(Function<? super T, ? extends U> mapper) {
return sortBy(U::compareTo, mapper);
}
@Override
public <U> Queue<T> sortBy(Comparator<? super U> comparator, Function<? super T, ? extends U> mapper) {
final Function<? super T, ? extends U> domain = Function1.of(mapper::apply).memoized();
return toJavaStream()
.sorted((e1, e2) -> comparator.compare(domain.apply(e1), domain.apply(e2)))
.collect(collector());
}
@Override
public Tuple2<Queue<T>, Queue<T>> span(Predicate<? super T> predicate) {
Objects.requireNonNull(predicate, "predicate is null");
return toList().span(predicate).map(io.vavr.collection.List::toQueue, io.vavr.collection.List::toQueue);
}
@Override
public Tuple2<Queue<T>, Queue<T>> splitAt(int n) {
return toList().splitAt(n).map(io.vavr.collection.List::toQueue, io.vavr.collection.List::toQueue);
}
@Override
public Tuple2<Queue<T>, Queue<T>> splitAt(Predicate<? super T> predicate) {
return toList().splitAt(predicate).map(io.vavr.collection.List::toQueue, io.vavr.collection.List::toQueue);
}
@Override
public Tuple2<Queue<T>, Queue<T>> splitAtInclusive(Predicate<? super T> predicate) {
return toList().splitAtInclusive(predicate).map(io.vavr.collection.List::toQueue, io.vavr.collection.List::toQueue);
}
@Override
public boolean startsWith(Iterable<? extends T> that, int offset) {
return toList().startsWith(that, offset);
}
@Override
public Queue<T> subSequence(int beginIndex) {
if (beginIndex < 0 || beginIndex > length()) {
throw new IndexOutOfBoundsException("subSequence(" + beginIndex + ")");
} else {
return drop(beginIndex);
}
}
@Override
public Queue<T> subSequence(int beginIndex, int endIndex) {
Collections.subSequenceRangeCheck(beginIndex, endIndex, length());
if (beginIndex == endIndex) {
return empty();
} else if (beginIndex == 0 && endIndex == length()) {
return this;
} else {
return ofAll(toList().subSequence(beginIndex, endIndex));
}
}
@Override
public Queue<T> tail() {
if (isEmpty()) {
throw new UnsupportedOperationException("tail of empty " + stringPrefix());
} else {
return new Queue<>(front.tail(), rear);
}
}
@Override
public Queue<T> take(int n) {
if (n <= 0) {
return empty();
}
if (n >= length()) {
return this;
}
final int frontLength = front.length();
if (n < frontLength) {
return new Queue<>(front.take(n), io.vavr.collection.List.empty());
} else if (n == frontLength) {
return new Queue<>(front, io.vavr.collection.List.empty());
} else {
return new Queue<>(front, rear.takeRight(n - frontLength));
}
}
@Override
public Queue<T> takeRight(int n) {
if (n <= 0) {
return empty();
}
if (n >= length()) {
return this;
}
final int rearLength = rear.length();
if (n < rearLength) {
return new Queue<>(rear.take(n).reverse(), io.vavr.collection.List.empty());
} else if (n == rearLength) {
return new Queue<>(rear.reverse(), io.vavr.collection.List.empty());
} else {
return new Queue<>(front.takeRight(n - rearLength), rear);
}
}
@Override
public Queue<T> takeUntil(Predicate<? super T> predicate) {
Objects.requireNonNull(predicate, "predicate is null");
final io.vavr.collection.List<T> taken = toList().takeUntil(predicate);
return taken.length() == length() ? this : ofAll(taken);
}
/**
* Transforms this {@code Queue}.
*
* @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 Queue<T>, ? extends U> f) {
Objects.requireNonNull(f, "f is null");
return f.apply(this);
}
@Override
public <T1, T2> Tuple2<Queue<T1>, Queue<T2>> unzip(
Function<? super T, Tuple2<? extends T1, ? extends T2>> unzipper) {
Objects.requireNonNull(unzipper, "unzipper is null");
return toList().unzip(unzipper).map(io.vavr.collection.List::toQueue, io.vavr.collection.List::toQueue);
}
@Override
public <T1, T2, T3> Tuple3<Queue<T1>, Queue<T2>, Queue<T3>> unzip3(Function<? super T, Tuple3<? extends T1, ? extends T2, ? extends T3>> unzipper) {
Objects.requireNonNull(unzipper, "unzipper is null");
return toList().unzip3(unzipper).map(io.vavr.collection.List::toQueue, io.vavr.collection.List::toQueue, io.vavr.collection.List::toQueue);
}
@Override
public Queue<T> update(int index, T element) {
return ofAll(toList().update(index, element));
}
@Override
public Queue<T> update(int index, Function<? super T, ? extends T> updater) {
Objects.requireNonNull(updater, "updater is null");
return update(index, updater.apply(get(index)));
}
@Override
public <U> Queue<Tuple2<T, U>> zip(Iterable<? extends U> that) {
return zipWith(that, Tuple::of);
}
@SuppressWarnings("unchecked")
@Override
public <U, R> Queue<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 ofAll(toList().zipWith(that, mapper));
}
@Override
public <U> Queue<Tuple2<T, U>> zipAll(Iterable<? extends U> that, T thisElem, U thatElem) {
Objects.requireNonNull(that, "that is null");
return ofAll(toList().zipAll(that, thisElem, thatElem));
}
@Override
public Queue<Tuple2<T, Integer>> zipWithIndex() {
return zipWithIndex(Tuple::of);
}
@Override
public <U> Queue<U> zipWithIndex(BiFunction<? super T, ? super Integer, ? extends U> mapper) {
Objects.requireNonNull(mapper, "mapper is null");
return ofAll(toList().zipWithIndex(mapper));
}
private Object readResolve() {
return isEmpty() ? EMPTY : this;
}
@Override
public String stringPrefix() {
return "Queue";
}
@Override
public boolean equals(Object o) {
return io.vavr.collection.Collections.equals(this, o);
}
@Override
public int hashCode() {
return io.vavr.collection.Collections.hashOrdered(this);
}
}