Returns the NSDocument subclass associated with document type docType . The document type must be one the document can read. If the class cannot be found, returns null . Returns the NSDocument object for the file in which the document data is stored. The fileName argument is a fully qualified path in the file system.
Returns null if no document can be found.
Returns null if window is null , if window has no window controller, or if the window controller does not have an association with an NSDocument. Returns the NSDocument objects managed by the receiver. If there are currently no documents, returns an empty NSArray. The first string in the returned NSArray is typically the most common extension. The array may also contain encoded HFS file types as will as file name extensions.