LeanMapperQuery suggested base classes.

BaseQuery.php

<?php

namespace Model\Entity;

use LeanMapperQuery\Entity;
use LeanMapperQuery\IQuery;
use Model\Query\EntityQuery;

class BaseEntity extends Entity
{
	protected static $magicMethodsPrefixes = array('findOne', 'findCount', 'find');


	protected function find($field, IQuery $query)
	{
		$entities = $this->queryProperty($field, $query);
		return $this->entityFactory->createCollection($entities);
	}

	protected function findOne($field, IQuery $query)
	{
		$query->limit(1);
		$entities = $this->queryProperty($field, $query);
		if ($entities) {
			return $entities[0];
		}
		return NULL;
	}

	protected function findCount($field, IQuery $query)
	{
		return count($this->queryProperty($field, $query));
	}

	protected function createQueryObject($field)
	{
		return new EntityQuery($this, $field);
	}

	public function __call($name, array $arguments)
	{
		if (preg_match('#^query(.+)$#', $name, $matches)) {
			return $this->createQueryObject($matches[1]);
		} else {
			return parent::__call($name, $arguments);
		}
	}

}

BaseRepository.php

<?php

namespace Model\Repository;

use LeanMapper\Repository;
use LeanMapperQuery\IQuery;
use Model\Query\RepositoryQuery;

class BaseRepository extends Repository implements IQueryable
{

	private function apply(IQuery $query)
	{
		$fluent = $this->createFluent();
		$query->applyQuery($fluent, $this->mapper);
		return $fluent;
	}

	public function query()
	{
		return new RepositoryQuery($this);
	}

	/**
	 * @param  IQuery $query
	 * @return Entity[]
	 */
	public function find(IQuery $query)
	{
		return $this->createEntities($this->apply($query)->fetchAll());
	}

	/**
	 * @param  IQuery $query
	 * @return Entity|NULL
	 */
	public function findOne(IQuery $query)
	{
		$row = $this->apply($query)
			->removeClause('limit')
			->removeClause('offset')
			->fetch();
		return $row ? $this->createEntity($row) : NULL;
	}

	/**
	 * @param  IQuery $query
	 * @return int
	 */
	public function findCount(IQuery $query)
	{
		return count($this->apply($query));
	}

}

EntityQuery.php

<?php

namespace Model\Query;

use LeanMapperQuery\Query;
use LeanMapperQuery\Entity;

class EntityQuery extends Query implements \Countable
{

	/** @var Entity */
	private $entity;

	/** @var string */
	private $field;


	public function __construct(Entity $entity, $field)
	{
		$this->entity = $entity;
		$this->field = $field;
	}

	public function find()
	{
		return $this->entity->{'find' . ucfirst($this->field)}($this);
	}

	public function findOne()
	{
		return $this->entity->{'findOne' . ucfirst($this->field)}($this);
	}

	public function count()
	{
		return $this->entity->{'findCount' . ucfirst($this->field)}($this);
	}

}

IQueryable.php

<?php

namespace Model\Repository;

use LeanMapperQuery\IQuery;
use LeanMapper\Entity;

interface IQueryable
{

	/**
	 * @param  IQuery $query
	 * @return Entity[]
	 */
	public function find(IQuery $query);

	/**
	 * @param  IQuery $query
	 * @return Entity
	 */
	public function findOne(IQuery $query);

	/**
	 * @param  IQuery $query
	 * @return int
	 */
	public function findCount(IQuery $query);
}

RepositoryQuery.php

<?php

namespace Model\Query;

use LeanMapperQuery\Query;
use Model\Repository\IQueryable;

class RepositoryQuery extends Query implements \Countable
{
	/** @var IQueryable */
	private $queryable;


	public function __construct(IQueryable $queryable)
	{
		$this->queryable = $queryable;
	}

	public function find()
	{
		return $this->queryable->find($this);
	}

	public function findOne()
	{
		return $this->queryable->findOne($this);
	}

	public function count()
	{
		return $this->queryable->findCount($this);
	}

}