src/GraphBuilder.php
public function filter( $expression ) {
		$this->expressionValidator->validate( $expression, ExpressionValidator::VALIDATE_FUNCTION );

		$this->usageValidator->trackUsedPrefixes( $expression );
		$this->usageValidator->trackUsedVariables( $expression );

		$this->filters[] = '(' . $expression . ')';

		return $this;
	}
public function filter( $expression ) {
		$this->expressionValidator->validate( $expression, ExpressionValidator::VALIDATE_FUNCTION );

		$this->usageValidator->trackUsedPrefixes( $expression );
		$this->usageValidator->trackUsedVariables( $expression );

		$this->filters[] = '(' . $expression . ')';

		return $this;
	}
public function filter ( $ expression ) { $ this -> expressionValidator -> validate ( $ expression , ExpressionValidator :: VALIDATE_FUNCTION ) ; $ this -> usageValidator -> trackUsedPrefixes ( $ expression ) ; $ this -> usageValidator -> trackUsedVariables ( $ expression ) ; $ this -> filters [ ] = '(' . $ expression . ')' ; return $ this ; }
Adds the given expression as a filter to this query.

@param string $expression
@return self
@throws InvalidArgumentException
Adds the given expression as a filter to this query .