QueryFactory.php

<?php

namespace Drupal\Core\Entity\Query\Sql;

use Drupal\Core\Database\Connection;
use Drupal\Core\Entity\EntityTypeInterface;
use Drupal\Core\Entity\Query\QueryBase;
use Drupal\Core\Entity\Query\QueryFactoryInterface;

/**
 * Factory class creating entity query objects for the SQL backend.
 *
 * @see \Drupal\Core\Entity\Query\Sql\Query
 * @see \Drupal\Core\Entity\Query\Sql\QueryAggregate
 */
class QueryFactory implements QueryFactoryInterface {
    
    /**
     * The database connection to use.
     *
     * @var \Drupal\Core\Database\Connection
     */
    protected $connection;
    
    /**
     * The namespace of this class, the parent class etc.
     *
     * @var array
     */
    protected $namespaces;
    
    /**
     * Constructs a QueryFactory object.
     *
     * Initializes the list of namespaces used to locate query
     * classes for different entity types.
     *
     * @param \Drupal\Core\Database\Connection $connection
     *   The database connection used by the entity query.
     */
    public function __construct(Connection $connection) {
        $this->connection = $connection;
        $this->namespaces = QueryBase::getNamespaces($this);
    }
    
    /**
     * {@inheritdoc}
     */
    public function get(EntityTypeInterface $entity_type, $conjunction) {
        $class = QueryBase::getClass($this->namespaces, 'Query');
        return new $class($entity_type, $conjunction, $this->connection, $this->namespaces);
    }
    
    /**
     * {@inheritdoc}
     */
    public function getAggregate(EntityTypeInterface $entity_type, $conjunction) {
        $class = QueryBase::getClass($this->namespaces, 'QueryAggregate');
        return new $class($entity_type, $conjunction, $this->connection, $this->namespaces);
    }

}