public function validate( $input )
    {
        // Check for minimum constraint
        if ( ( $this->min !== false ) &&
             ( $input < $this->min ) )
        {
            throw new phpillowValidationException(
                'Input value %input is not bigger or equal then %minimum.',
                array(
                    'input'   => $input,
                    'minimum' => $this->min,
                )
            );
        }

        // Check for maximum constraint
        if ( ( $this->max !== false ) &&
             ( $input > $this->max ) )
        {
            throw new phpillowValidationException(
                'Input value %input is not lesser or equal then %maximum.',
                array(
                    'input'   => $input,
                    'maximum' => $this->max,
                )
            );
        }

        return (float) $input;
    }