ios - Confused on Document Based iPhone App Guide -

i'm writing 1 of first iphone apps - simple way of remembering things people. i'm following ios document called "document-based app programming guide ios" , i've gotten point query local device , icloud detect , load documents. in guide use custom class , since don't show code class, i'm confused on should like. give description of custom class "filerepresentation":

the example application has array (_filelist) of custom model objects encapsulate name , file url of each of application’s documents. (filerepresentation custom class of objects.)

can give example of "filerepresentation"'s class implementation like?

the parts listing 4-3 , 4-4 on page "managing lifecycle of document":

listing 4-3

-(void)viewdidload {     [super viewdidload];     // set add , edit navigation items here....     if (self.documentsincloud) {         _query = [[nsmetadataquery alloc] init];         [_query setsearchscopes:[nsarray arraywithobjects:nsmetadataqueryubiquitousdocumentsscope, nil]];         [_query setpredicate:[nspredicate predicatewithformat:@"%k '*.txt'", nsmetadataitemfsnamekey]];         nsnotificationcenter* notificationcenter = [nsnotificationcenter defaultcenter];         [notificationcenter addobserver:self selector:@selector(filelistreceived)             name:nsmetadataquerydidfinishgatheringnotification object:nil];         [notificationcenter addobserver:self selector:@selector(filelistreceived)             name:nsmetadataquerydidupdatenotification object:nil];         [_query startquery];     } else {         nsarray* localdocuments = [[nsfilemanager defaultmanager] contentsofdirectoryatpath:             [self.documentsdir path] error:nil];         (nsstring* document in localdocuments) {             [_filelist addobject:[[[filerepresentation alloc] initwithfilename:[document lastpathcomponent]             url:[nsurl fileurlwithpath:[[self.documentsdir path]             stringbyappendingpathcomponent:document]]] autorelease]];         }     } } 

listing 4-4

-(void)filelistreceived {      nsstring* selectedfilename=nil;      nsinteger newselectionrow = [self.tableview indexpathforselectedrow].row;      if (newselectionrow != nsnotfound) {         selectedfilename = [[_filelist objectatindex:newselectionrow] filename];      }      [_filelist removeallobjects];      nsarray* queryresults = [_query results];      (nsmetadataitem* result in queryresults) {          nsstring* filename = [result valueforattribute:nsmetadataitemfsnamekey];          if (selectedfilename && [selectedfilename isequaltostring:filename]) {              newselectionrow = [_filelist count];          }          [_filelist addobject:[[[filerepresentation alloc] initwithfilename:filename              url:[result valueforattribute:nsmetadataitemurlkey]] autorelease]];      }      [self.tableview reloaddata];      if (newselectionrow != nsnotfound) {          nsindexpath* selectionpath = [nsindexpath indexpathforrow:newselectionrow insection:0];          [self.tableview selectrowatindexpath:selectionpath animated:no scrollposition:uitableviewscrollpositionnone];      }  } 

for people see in future, worked out seeing how other classes implement init functions:

#import "filerepresentation.h"  @implementation filerepresentation  @synthesize filename = _filename, fileurl=_fileurl;  -(id) initwithfilename:(nsstring*)filename url:(nsurl*)url {     self = [super init];     if(self){         self.filename = filename;     }     return self; }  @end