/**
  * filter
  *
  * Filter the query
  * 
  * @param  \Doctrine\MongoDB\Query\Builder $qb
  * @return \Doctrine\MongoDB\Query\Expr
  */
 public function filter(Query\Builder $qb)
 {
     $spec = SF::isEqual($this->fieldName, $this->fieldValue);
     return $this->spec->filter($qb);
 }
 /**
  * filter
  *
  * Perform the specification filtering
  * 
  * @param  \Dcotrine\MongoDb\Query\Builder $qb
  * @return \Dcotrine\MongoDb\Query\Expr
  */
 public function filter(Query\Builder $qb)
 {
     $spec = SF::isEqual($this->fieldName . '._id', new \MongoId($this->fieldValue));
     return $spec->filter($qb);
 }
 /**
  * filter
  *
  * Perform the filter on the query builder
  * 
  * @param  \Doctrine\MongoDB\Query $qb
  * @return \Doctrine\MongoDB\Query\Expr
  */
 public function filter(Query\Builder $qb)
 {
     $spec = SF::isEqual($fieldName, new \MongoRegex($regex));
     return $spec->filter($qb);
 }