wikimedia/mediawiki-extensions-Wikibase

<?php

namespace Wikibase\DataModel\Entity;

use ArrayIterator;
use Countable;
use InvalidArgumentException;
use IteratorAggregate;
use Traversable;

/**
 * Immutable set of ItemId objects. Unordered and unique.
 * The constructor filters out duplicates.
 *
 * @since 0.7.4
 *
 * @license GPL-2.0-or-later
 * @author Jeroen De Dauw < jeroendedauw@gmail.com >
 */
class ItemIdSet implements IteratorAggregate, Countable {

    /**
     * @var ItemId[]
     */
    private $ids = [];

    /**
     * @param ItemId[] $ids
     *
     * @throws InvalidArgumentException
     */
    public function __construct( array $ids = [] ) {
        foreach ( $ids as $id ) {
            if ( !( $id instanceof ItemId ) ) {
                throw new InvalidArgumentException( 'Every element in $ids must be an instance of ItemId' );
            }

            $this->ids[$id->getNumericId()] = $id;
        }
    }

    /**
     * @see Countable::count
     *
     * @return int
     */
    public function count(): int {
        return count( $this->ids );
    }

    /**
     * @see IteratorAggregate::getIterator
     *
     * @return Iterator|ItemId[]
     */
    public function getIterator(): Traversable {
        return new ArrayIterator( $this->ids );
    }

    /**
     * @since 2.5
     *
     * @return string[]
     */
    public function getSerializations() {
        return array_values(
            array_map(
                static function( ItemId $id ) {
                    return $id->getSerialization();
                },
                $this->ids
            )
        );
    }

    /**
     * @param ItemId $id
     *
     * @return bool
     */
    public function has( ItemId $id ) {
        return array_key_exists( $id->getNumericId(), $this->ids );
    }

    /**
     * @see Countable::equals
     *
     * @since 0.1
     *
     * @param mixed $target
     *
     * @return bool
     */
    public function equals( $target ) {
        if ( $this === $target ) {
            return true;
        }

        return $target instanceof self
            && $this->ids == $target->ids;
    }

}