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eof-notes

CREATED BY chris • LAST EDITED BY chris 7954 days AGO

- "Compared to subclassing, delegation is usually a more elegant solution to extend or customize the behavior of a class." — (Delegation in this context means providing hooks for extension or adaption of behaviour.)

- Notification provides for a central inter-object change notification facility (willRead, willChange). Important for faulting.

- Faulting (delayed data fetching): Only fully initialize objects if needed (memory consumption, performance).

- If behaviour needs to be added, subclass EOGenericRecord. For less magic subclass EOCustomObject.

- EOGenericRecord stores attributes in an internal dictionary (flexibility).

- "[A]lways program to the interface rather than to the implementation."

- object.valueForKey("key"), object.valueForKeyPath("author.name"), object.takeValueForKey(value, "key")

- Key-value-coding: indirect attribute access (softwiring) — "[C]onsistent way to access an object’s data, regardless if the object provides accessor methods or fields to its data" — fallback chain for read: getKeyname(), keyname(), _getKeyname(), _keyname(), keyname, _keyname, handleQueryWithUnboundKey("keyname"), fallback chain for write: setKeyname(value), _setKeyname(value), keyname, _keyname, handleTakeValueForUnboundKey(value, "keyname")

- "As a cardinal rule, all enterprise objects reside in an editing context. This is necessary in order for enterprise objects to send and receive the notifications necessary for change tracking and other mechanisms within Enterprise Objects. So, for every enterprise object you create, you must immediately insert it into an editing context."

- Default value setting hooks: set in awakeFromInsertion (new object), awakeFromFetch (Q: why not specify declaratively as part of the model?)

- Validation hooks: validateClientUpdate, validateForDelete, validateForInsert, validateForSave, validateForUpdate — default implementations for Save, Insert, Update call validateValueForKey