/**
 * @license
 * Copyright Larry Diamond 2018 All Rights Reserved.
 *
 * Use of this source code is governed by an MIT-style license that can be
 * found in the LICENSE file at https://github.com/larrydiamond/typescriptcollectionsframework/blob/master/LICENSE
 */
import { ImmutableCollection } from "./ImmutableCollection";
import { ImmutableSet } from "./ImmutableSet";
import { JIterator } from "./JIterator";
/**
 * An immutable collection that may contain duplicate elements. (Or at least elements that are equal to one another)
 *
 * The purpose of this interface is to provide Navigable and Sorted implementations of Multisets that may contain duplicate elements.
 */
export interface ImmutableMultiSet<K> extends ImmutableCollection<K> {
    /**
    * Returns the number of occurrences of an element in this MultiSet (the count of the element).
    * @param {K} item the element to count occurrences of
    * @return {number} the number of occurrences of the element in this MultiSet; possibly zero but never negative
    */
    count(item: K): number;
    /**
     * Returns an ImmutableSet view of the keys contained in this MultiSet.
     * The ImmutableSet is backed by the MultiSet, so changes to the MultiSet are reflected in the returned ImmutableSet.
     * If the MultiSet is modified while an iteration over the returned ImmutableSet is in progress the results of the iteration are undefined.
     * @return {ImmutableSet<K>} a view of the set of distinct keys in this MultiSet
     */
    keySet(): ImmutableSet<K>;
    /**
     * Returns the number of elements in this MultiSet (its cardinality).
     * @return {number} the number of elements in this MultiSet (its cardinality)
     */
    size(): number;
    /**
     * Returns true if this MultiSet contains no elements.
     * @return {boolean} true if this MultiSet contains no elements
     */
    isEmpty(): boolean;
    /**
     * Returns true if this MultiSet contains the specified element.   This method uses the comparator and does not invoke equals
     * @param {K} item object to be checked for containment in this MultiSet
     * @return {boolean} true if this MultiSet contains the specified element
     */
    contains(item: K): boolean;
    /**
      * Returns a Java style iterator
      * @return {JIterator<K>} the Java style iterator
      */
    iterator(): JIterator<K>;
    /**
     * Returns a TypeScript style iterator
     * @return {Iterator<K>} the TypeScript style iterator
     */
    [Symbol.iterator](): Iterator<K>;
}