Quick start problem

[superandrew]

Hello, I am having trouble setting ap FEM.

This is my code:

@implementation MappingProvider

+ (FEMManagedObjectMapping *)chromosomeMapping {
    return [FEMManagedObjectMapping mappingForEntityName:@"Chromosome" configuration:^(FEMManagedObjectMapping *mapping) {

    [mapping setPrimaryKey:@"chromosomeID"];  // object uniquing


    //[mapping addRelationshipMapping:[self carMapping] forProperty:@"car" keyPath:@"car"];
    [mapping addToManyRelationshipMapping:[self geneMapping] forProperty:@"genes" keyPath:@"genes"];
}];
}

+ (FEMManagedObjectMapping *)mutationMapping {
    return [FEMManagedObjectMapping mappingForEntityName:@"Mutation" configuration:^(FEMManagedObjectMapping *mapping) {
    [mapping setPrimaryKey:@"mutationID"];

    //[mapping addAttributeMappingFromArray:@[@"model", @"year"]];
    }];
}

+ (FEMManagedObjectMapping *)geneMapping {
    return [FEMManagedObjectMapping mappingForEntityName:@"Gene" configuration:^(FEMManagedObjectMapping *mapping) {
       [mapping setPrimaryKey:@"geneID"];
    //[mapping addAttributeMappingFromArray:@[@"number", @"ddd", @"ddi"]];
        [mapping addToManyRelationshipMapping:[self mutationMapping] forProperty:@"variations" keyPath:@"variations"];
    }];
}

@end`

And how I call it:

Chromosome *c = [FEMManagedObjectDeserializer deserializeObjectExternalRepresentation:chr usingMapping:[MappingProvider chromosomeMapping] context:_setupContext];

I have this error

*** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'Invalid parameter not satisfying: primaryKeyMapping'
*** First throw call stack:
(
0 CoreFoundation 0x000000010dbca495 __exceptionPreprocess + 165
1 libobjc.A.dylib 0x000000010d92499e objc_exception_throw + 43
2 CoreFoundation 0x000000010dbca31a +[NSException raise:format:arguments:] + 106
3 Foundation 0x000000010d4bbf19 -[NSAssertionHandler handleFailureInMethod:object:file:lineNumber:description:] + 189
4 Exome Scan 0x000000010c8676a2 -[FEMCache inspectObjectRepresentation:usingMapping:] + 450

Any idea?

[superandrew]

I guess the problem was that I needed to import the fields I was planning to use as primarykey, so:

[mapping setPrimaryKey:@"chromosomeID"];  // object uniquing
    [mapping addAttributeMappingFromArray:@[@"chromosomeID",@"chrNum",@"descriptionKey",@"knownGenes", @"knownVariations",@"nonSynonymous", @"nucleotides",@"synonymous",@"titleKey", @"unknown"]];

kinda fixed the problem.

However i have a question: how to deal with JSON parameters like "chrNum":"23" which FEM expects to be NSNumber?

2014-10-06 11:30:23.374 Exome Scan[6395:360f] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'Unacceptable type of value for attribute: property = "chrNum"; desired type = NSNumber; given type = __NSCFString; value = 1.'

Thanks

[dimazen]

Sorry, out of laptop for about a week. Take a look at custom FEMAttributeMapping: in map & reverse map you can specify your custom mapping. I.e.

Map: ^(id value) { // check whether it is a nsstring; return [value integerValue]; }

[superandrew]

thank you very much, I'll look at it.

[superandrew]

Honestly I didn't understand, I'm sorry. Is there any documentation available? Thank you very much for help.

[dimazen]

@superandrew
Sorry for docs.
Here is what you need:

[mapping addAttributeMapping:[FEMAttributeMapping mappingOfProperty:@"chrNum" toKeyPath:@"chrNum" map:^id(id value) {
    return [value isKindOfClass:NSString.class] ? @([value integerValue]) : NSNull.null;
} reverseMap:^id(NSNumber *value) {
    return [value stringValue];
}]];

[superandrew]

You don't have to sorry, It's a gift that this project exists. Thank you very much for your passion and commitment.

[superandrew]

Ok, so I understood how this work, but exactly what do exactly "map" and "reverseMap" means by a semantic perspective? They are two blocks which should do exactly which kind of operation? reverseMap seems to convert the actual value to the expected class, but it's not clear for "map".

I'm sorry, maybe it's really simple but I just don't get it :(

[dimazen]

@superandrew
i was thinking on this part as well. As the result: probable "transform" & "reverseTransform" are better.
map is used, then you deserializing Dictionary into Object.
reverseMap is used for Serializing Object into Dictionary.

[dimazen]

The core idea behind it is to provide flexible way of mapping JSON input into any kind of data you'd like to and vice versa.

Take a look at +[FEMAttributeMapping mappingOfProperty:toKeyPath:dateFormat:] to understand, what you can do with all those blocks

[dimazen]

@superandrew do you need any help to this question?

[superandrew]

Everything is clear, thank you very much.