[aerogear-dev] iOS/CoreData - API proposal - AGEntityMapper

[Matthias Wessendorf]

did a quick update on the gist:

https://gist.github.com/843c89668b2216929633

;-)



On Fri, Jan 4, 2013 at 4:08 PM, Matthias Wessendorf <matzew at apache.org>wrote:

> that's the idea
>
>
> On Fri, Jan 4, 2013 at 3:07 PM, Douglas Campos <qmx at qmx.me> wrote:
>
>> Ah so the mapping is reversed then?
>>
>> On 04/01/2013, at 11:16, Matthias Wessendorf <matzew at apache.org> wrote:
>>
>> > There is some code in Mantle, which does that; my look up mechanism
>> will borrow that - but that's an impl detail
>> >
>> > The mapper goal is really just to say JSON "key" 'blah' is mapped to
>> 'foo' on the actual bean (not about the specific types)
>> >
>> > Makes sense?
>> >
>> > -M
>> >
>> >
>> > On Fri, Jan 4, 2013 at 2:09 PM, Douglas Campos <qmx at qmx.me> wrote:
>> > how the mapper deals with nested objects?
>> >
>> > On 04/01/2013, at 08:55, Matthias Wessendorf <matzew at apache.org> wrote:
>> >
>> > > CoreData: API proposal - AGEntityMapper
>> > > Background
>> > > Mapping JSON representations to a "rich" domain model in ObjC is a
>> bit cumbersome. Similar is true when mapping a JSON data/response to a
>> NSMangedObject (and vise versa). There is a base framework for "remote
>> persistence", via the CoreData API, by leveraging a custom
>> NSIncrementalStore -> AFIncrementalStore.
>> > >
>> > > For that,... a similar two-way-mapping is required, as described here.
>> > >
>> > > AeroGear and CoreData
>> > > Our CoreData offerings are leveraging the AFIncrementalStore,
>> therefore (as with other frameworks/libraries) we need a mapping as well.
>> We need to know the name of the entity and we need a NSDictionary that
>> covers the actual JSON/property mapping. It could be done with the vanialla
>> ObjC classes:
>> > >
>> > > // some mappers:
>> > > NSDictionary *task_mapper =
>> > >
>> > >
>> > > [NSDictionary dictionaryWithObjectsAndKeys:@"description",@"desc",@"id",@"myId",
>> nil];
>> > > NSDictionary *project_mapper =
>> > >
>> > >
>> > > [NSDictionary dictionaryWithObjectsAndKeys:@"id",@"myId", nil];
>> > >
>> > >
>> > >
>> > > // create a schema out of the mappers:
>> > > NSDictionary *schema =
>> > >
>> > >
>> > > [NSDictionary dictionaryWithObjectsAndKeys:task_mapper, @"Task",
>> project_mapper, @"Project", nil];
>> > >
>> > >
>> > >
>> > > // pass the schema to the AGCoreDataHelper class, when doing the
>> init...
>> > > Proposal for a custom API
>> > > I'd like to introduce a new wrapper type, called AGEntityMapper:
>> > >
>> > > @interface AGEnityMapper : NSObject
>> > >
>> > >
>> > >
>> > > @property NSString *name;
>> > > @property NSDictionary *mapper;
>> > >
>> > >
>> > >
>> > > -(id) initWithName:(NSString *) name mapper:(NSDictionary *) mapper;
>> > > @end
>> > > This AGEntityMapper would be applied onto the AGCoreDataConfig:
>> > >
>> > > @protocol AGCoreDataConfig <NSObject>
>> > >
>> > >
>> > >
>> > > @property (strong, nonatomic) NSManagedObjectModel
>> *managedObjectModel;
>> > > @property (strong, nonatomic) NSURL *baseURL;
>> > >
>> > >
>> > >
>> > > -(void)applyEntityMappers:(AGEnityMapper *)firstObject, ...
>> NS_REQUIRES_NIL_TERMINATION;
>> > >
>> > >
>> > >
>> > > @end
>> > > The actual code, would look like this:
>> > >
>> > > EnityMapper *taskMapper =
>> > >
>> > >
>> > > [[EnityMapper alloc] initWithName:@"Task"
>> > >
>> > >
>> > > // mapping the properties on the "entity" (NSManagedObject)
>> > >
>> > >
>> > > // to the external representation (e.g. JSON)
>> > >
>> > >
>> > > mapper:@{ @"desc": @"description", @"myId": @"id"}];
>> > >
>> > >
>> > >
>> > > EnityMapper *projectMapper =
>> > >
>> > >
>> > > [[EnityMapper alloc] initWithName:@"Project"
>> > >
>> > >
>> > > // mapping the properties on the "entity" (NSManagedObject)
>> > >
>> > >
>> > > // to the external representation (e.g. JSON)
>> > >
>> > >
>> > > mapper:@{ @"myId": @"id"}];
>> > >
>> > >
>> > >
>> > > AGCoreDataHelper *helper = [[AGCoreDataHelper alloc]
>> initWithConfig:^(id<AGCoreDataConfig> config) {
>> > >
>> > >
>> > >
>> > > [config setBaseURL:[NSURL URLWithString:@"http://server.com"]];
>> > >
>> > >
>> > >
>> > > [config applyEntityMappers:
>> > >
>> > >
>> > > taskMapper,
>> > >
>> > >
>> > > projectMapper,
>> > >
>> > >
>> > > nil // terminate the varargs.
>> > >
>> > >
>> > > ];
>> > > }];
>> > >
>> > > --
>> > > Matthias Wessendorf
>> > >
>> > > blog: http://matthiaswessendorf.wordpress.com/
>> > > sessions: http://www.slideshare.net/mwessendorf
>> > > twitter: http://twitter.com/mwessendorf
>> > > _______________________________________________
>> > > aerogear-dev mailing list
>> > > aerogear-dev at lists.jboss.org
>> > > https://lists.jboss.org/mailman/listinfo/aerogear-dev
>> >
>> >
>> > _______________________________________________
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>> >
>> >
>> >
>> > --
>> > Matthias Wessendorf
>> >
>> > blog: http://matthiaswessendorf.wordpress.com/
>> > sessions: http://www.slideshare.net/mwessendorf
>> > twitter: http://twitter.com/mwessendorf
>> > _______________________________________________
>> > aerogear-dev mailing list
>> > aerogear-dev at lists.jboss.org
>> > https://lists.jboss.org/mailman/listinfo/aerogear-dev
>>
>>
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>
>
>
> --
> Matthias Wessendorf
>
> blog: http://matthiaswessendorf.wordpress.com/
> sessions: http://www.slideshare.net/mwessendorf
> twitter: http://twitter.com/mwessendorf
>



-- 
Matthias Wessendorf

blog: http://matthiaswessendorf.wordpress.com/
sessions: http://www.slideshare.net/mwessendorf
twitter: http://twitter.com/mwessendorf
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