(No version information available, might be only in CVS)
Serializable::serialize — String representation of object
Should return the string representation of the object.
注意: This method acts as the destructor of the object. The __destruct() method will not be called after this method.
この関数にはパラメータはありません。
Returns the string representation of the object or NULL
Throws Exception when returning other types then strings and NULL