getValue() === $this->getValue(); } public function getValue() { return null; } public function getDbFormat() { return 'json'; } public function setValue($value) { if (! is_null($value)) { throw new ProgrammingError( 'Null can only be null, got %s', var_export($value, 1) ); } return $this; } public function toConfigString() { return 'null'; } }