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Ensuring KVC Compliance

In order for a class to be considered KVC compliant for a specific property, it must implement the methods required for valueForKey: and setValue:forKey: to work for that property.

Contents:

Attribute and To-One Relationship Compliance
Indexed To-Many Relationship Compliance
Unordered To-Many Relationship Compliance

Attribute and To-One Relationship Compliance

For properties that are an attribute or a to-one relationship, this requires that:

• Your class implements a method named -<key>, -is<Key>, or has an instance variable <key> or _<key>.

• If the property is mutable, then it should also implement -set<Key>:.

• Your implementation of the -set<Key>: method should not perform validation.

• Your class should implement -validate<Key>:error: if validation is appropriate for the key.

Indexed To-Many Relationship Compliance

For indexed to-many relationships, KVC compliance requires that your class:

• Implements method named -<key> that returns an array.

• Or has an array instance variable named <key> or _<key>.

• Or implements the method -countOf<Key> and one or both of -objectIn<Key>AtIndex: or -<key>AtIndexes:.

• Optionally, you can also implement -get<Key>:range: to improve performance.

For a indexed ordered to-many relationship, KVC compliance requires that your class also:

• Implement one or both of the methods -insertObject:in<Key>AtIndex: or -insert<Key>:atIndexes:.

• Implement one or both of the methods -removeObjectFrom<Key>AtIndex: or -remove<Key>AtIndexes:.

• Optionally, you can also implement -replaceObjectIn<Key>AtIndex:withObject: or -replace<Key>AtIndexes:with<Key>: to improve performance.

Unordered To-Many Relationship Compliance

For unordered to-many relationships, KVC compliance requires that your class:

• Implements method named -<key> that returns a set.

• Or has an set instance variable named <key> or _<key>.

• Or implements the methods -countOf<Key>, -enumeratorOf<Key>, and -memberOf<Key>:.

For a mutable unordered to-many relationship, KVC compliance requires that your class also:

• Implement one or both of the methods -add<Key>Object: or -add<Key>:.

• Implement one or both of the methods -remove<Key>Object: or -remove<Key>:.

• Optionally, you can also implement -intersect<Key>: and -set<Key>: to improve performance.

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