Last updated at 12:02 pm UTC on 12 January 2019
structures Dictionary of (#Rectangle ->#(classVersionInteger 'origin' 'corner')). Inst
var names are strings.
steady Set of Classes who have the same structure now as on the incoming file.
Includes classes with same inst vars except for new ones added on the end.
reshaped Dictionary of Classes who have a different structure now from the incoming file.
Includes those with same inst vars but new version number.
(old class name - method selector to fill in data for version to version)
renamed Dictionary of Classes who have a different name. Make an instance of the new
class, and send it the conversion call.
(old class name symbol ->new class name).
renamedConv Dictionary of conversion selector for Classes who have a different name.
(old class name symbol - conversion selector).
topCall Tells if next or nextPut: are working on the top object in the tree.
nil if outside, the top object if deep inside.
The core of saving an object called 'theObject' (and its subobjects) with a SmartRefStream is
srefStream := SmartRefStream on: theObject.
srefStream nextPut: theObject. "and all subobjects"
srefStream close. "also closes me"
OrdinaryReferenceStreams assume that the inames and order of instance variables/i/span is exactly the same when an object file is written and read.
SmartRefStream allows object files to be read even after iinstance variables have changed/i or the entire iclass has been renamed/i.
When an object file is written, no one knows how the classes will change in the future. Therefore, all conversion must be done when the file is read. The key is to store enough information in the file about the names of the instance variables of all outgoing classes.
SmartRefStream works best with only one tree of objects per file. You can nextPut: more than once, but each object tree gets its own class structure description, which is big.
Conversion of old objects is done by a method
seeSmartRefStream conversion methods–Ted Kaehler and Bob Arning.
What does SmartRefStream write out / Help for debugging
The SmartRefStream deals with
- class version
- class structure
- the objects themselvesdetails!! SmartRefStream is used when exporting an ImageSegment
Mariano Martinez Peck 1, Noury Bouraqadi, Stéphane Ducasse, Luc FabresseObject Swapping Challenges - an Evaluation of ImageSegment_
- Project Loading(A SmartRefStream is used to save/load *.pr files – project files)
- Ma Serializer(other non-related serialization mechanism)
- Fuel serializer (other non-related serialization mechanism)