iphone - iOS RestKit what is the purpose of [mappingProvider setMapping:forKeyPath:] method? -

i'm working through restkit relationship mapping example , cannot understand purpose of these method calls, or if there's typo in calls. refer to? when object loader encounter content @ these key paths?

[objectmanager.mappingprovider setmapping:usermapping forkeypath:@"user"]; [objectmanager.mappingprovider setmapping:taskmapping forkeypath:@"task"]; [objectmanager.mappingprovider setmapping:projectmapping forkeypath:@"project"]; 

the json file being loaded data has 3 objects: project, tasks , user. note tasks plural.

there 3 entities defined in core data model: user, task , project. these start capital letters.

finally, nsmanagedobject classes derived data model have relationships: task>assigneduser , user>tasks , project being regular nsobject

should @"task" @"tasks"?

@implementation rkrelationshipmappingexample  - (id)initwithnibname:(nsstring *)nibnameornil bundle:(nsbundle *)nibbundleornil {     self = [super initwithnibname:nibnameornil bundle:nibbundleornil];     if (self) {         rkobjectmanager* objectmanager = [rkobjectmanager objectmanagerwithbaseurl:grkcatalogbaseurl];         objectmanager.objectstore = [rkmanagedobjectstore objectstorewithstorefilename:@"rkrelationshipmappingexample.sqlite"];           rkmanagedobjectmapping* taskmapping = [rkmanagedobjectmapping mappingforclass:[task class]];         [taskmapping mapkeypath:@"id" toattribute:@"taskid"];         [taskmapping mapkeypath:@"name" toattribute:@"name"];         [taskmapping mapkeypath:@"assigned_user_id" toattribute:@"assigneduserid"];         taskmapping.primarykeyattribute = @"taskid"; //uniquely identifies record update purposes          rkmanagedobjectmapping* usermapping = [rkmanagedobjectmapping mappingforclass:[user class]];         [usermapping mapattributes:@"name", @"email", nil];         [usermapping mapkeypath:@"id" toattribute:@"userid"];         usermapping.primarykeyattribute = @"userid";           [objectmanager.mappingprovider setmapping:usermapping forkeypath:@"user"];         [objectmanager.mappingprovider setmapping:taskmapping forkeypath:@"task"];          [usermapping maprelationship:@"tasks" withmapping:taskmapping];                 [taskmapping maprelationship:@"assigneduser" withmapping:usermapping];          [taskmapping connectrelationship:@"assigneduser" withobjectforprimarykeyattribute:@"assigneduserid"];           // note - project not backed core data         rkobjectmapping* projectmapping = [rkobjectmapping mappingforclass:[project class]];         [projectmapping mapkeypath:@"id" toattribute:@"projectid"];         [projectmapping mapattributes:@"name", @"description", nil];         [projectmapping maprelationship:@"user" withmapping:usermapping];         [projectmapping maprelationship:@"tasks" withmapping:taskmapping];         [objectmanager.mappingprovider setmapping:projectmapping forkeypath:@"project"];        }      return self; }  //more code @end 

thank clarification!

the rkobjectmappingprovider setmapping:forkeypath: method instructs mapping provider object mapping use when encounters data @ given key path. in case of example , associated json data, there no actual instances of task keypaths -- in particular example, [objectmanager.mappingprovider setmapping:taskmapping forkeypath:@"task"] statement not required; in case, might have like

"task":{"id":10,"name":"some task", "assigned_user_id":5} 

in case would required. actual tasks in json stream mapped because of [projectmapping maprelationship:@"tasks" withmapping:taskmapping].

you can use rklogconfigurebyname() inspect restkit doing -- useful. rklogconfigurebyname("restkit/objectmapping", rklogleveltrace) in case give "blow-by-blow" of mapping logic.