KeyValueCoding

KVC resolves a binding like $name to a method or field on the component.

Reading

First match wins. Public members only.

1. getName()
2. name()
3. isName()
4. _getName()
5. _name()
6. _isName()
7. field name
8. field _name
9. field _isName
10. field isName

No match throws UnknownKeyException, with a suggestion: "Did you mean 'name'?". In a template, it shows as an error box in the page.

Setting

Forms set bindings on submit.

1. setName( value )
2. field name

Strings are converted when the target is a number.

Keypaths

$company.manager.name resolves each key on the result of the previous one.

A null anywhere makes the whole keypath null, with no NullPointerException. Setting through a null fails.

Maps and custom lookups

Maps aren't supported: $map.key doesn't read the map's entry (#36). To customise lookups, implement NGKeyValueCoding (valueForKey, takeValueForKey).

From Java

Object name = NGKeyValueCoding.Utility.valueForKey( user, "name" );
NGKeyValueCoding.Utility.takeValueForKey( user, "Jane", "name" );

Lookups are cached per class and key in production, but not in development.