Wondering if its possible to concatenate keyPaths to one attribute in mapping objects. Looking for something like
mapKeyPaths #"firstname", #"lastname", nil toAttribute:#"name"
Where name would then be "Bob Johnson"
** The API I am dealing with passes over a date and a startTime attribute, as 2012/02/28 and 16:12 respectively, as Strings.
It would be easier to just use startTime as "2012/02/28 16:12".
I figured I can get around this issue by leaving the date and startTime as NSDate fields, so I have tried setting up a dateFormatter per Restkits instructions. When I tried that idea, just using "HH:MM", for the startTime dateFormatter, it shoves "1970/01/01 16:12" into the startTime field.
Anyone have any suggestions, besides going through each record manually after mapping to Core Data and putting the fields in programatically?
I don't think you can do these kind of programmatic mappings yet.
Two alternative solutions come to mind:
1) In willMapData (or something like that) you can manually modify the incoming serialization before object mapping occurs. There you can specify a format you like.
2) Save both these properties in your Core Data entity and create a third transient attribute which is calculated at runtime, and when required, by passing these two values through a NSDateFormatter.
Related
In my data model, some of the attributes have regular expressions used for data validation. There are places in my code that I would like to use those same regular expressions.
In the interest of keeping my common regular expressions in one place, I was hoping either to set these regexes in code or to retrieve them from the data model in code.
Is there a way to do this?
I want to access the Reg. Ex. property, shown below, in code.
From a NSEntityDescription you can get its attributes with the method attributesByName. Then you can use the NSPropertyDescription methods validationPredicates and setValidationPredicates:withValidationWarnings:. I assume that a predicate is created under the hood when you set the validation regex in your datamodel file...
I am not completely sure about this, but I think you can only set these values when you are creating your core data model, not once you have your core data stack set up. Is that what you want to do?
Absolutely. Everything you do in the model editor can be done or modified in code by manipulating your NSManagedObjectModel object.
Locate where the model is retrieved in your core data stack setup (maybe in your app delegate). Before returning the model, modify it in code, using constants you can #define in a central include file.
Read all about the object model's API here. More precisely, you set the model's entities after modifying an entity description, by changing the validationPredicates of one of its attributes.
I marked e1985's answer as accepted, since that's the answer that led me here. Here's the code I used to get the predicate. It's in a category for NSEntityDescription.
- (NSPredicate*)getValidationPredicateForAttribute:(NSString*)attributeName
{
NSAttributeDescription* emailAttribute = [self.attributesByName objectForKey:attributeName];
NSArray* validationPredicates = [emailAttribute validationPredicates];
if(validationPredicates.count > 0)
{
return [validationPredicates objectAtIndex:0];
}
return nil;
}
Specifically, say I have an NSManagedObject with a "statusCode" attribute set to transformable, and a reversible value transformer subclass to covert from NSStrings to NSNumbers and vice versa. The idea is to use the value transformer so that I receive JSON and a string from a "status" key in the JSON automatically maps to an NSNumber that represents that status code in an NSManagedObject. Conversely if I were to upload the NSManagedObject to a server, at that point its status attribute would be transformed from an NSNumber to a string for the JSON.
So far so good. But, what if I also want to be able to get a simple int out of the NSManagedObjec's status property, so that I can AND it with enums in code?
That is, I'd lie to cover 3 cases:
myManagedObject.status = [JSONResponse valueForKey:#"status"] (should use transformer to do NSString -> NSNumber)
[JSONforUpload setValue:myManagedObject.status forKey:#"status"] (should use transformer to do NSNumber->NSString)
From elsewhere in code, anything along the lines of: if(myManagedObject.status & statusInProgress) ... where statusInProgress is an enum.
I'm thinking I could temporarily disable the value transformer, however I have no idea if the NSManagedObject has a reference to it, or if I should disable it from the NSValueTransformer class, which apparently keeps a table of registered transformers?
I know that for the 3rd case I could just do [myManagedObject.status intValue] and then do the bitwise comparison, but I'm wondering if there's any way I can have the intValue] be returned automagically, from the user of this object's point of view.
Any ideas?
Why don't you just write two additional methods for the JSON transform and leave the property as integer? Then you'd have the best from both worlds.
One approach would be to add a property to the transformer so that it switches between string and enum reversed values. That would work, though I ended up doing a enum<->string transformer and not using it over a transformable attribute (instead I left the managed object's attribute as int) but rather instantiating it only for the JSON <-> object conversion. After that, throughout code I just use the int attribute as is.
Assuming that this entity has its own distinct managed object subclass, you could also simply add another pair of accessor methods to the class to encapsulate the conversion between NSNumber and int values. (Or add a transient attribute, if it needs to be part of the model. But you'd still need to write custom accessors to synch up the values.)
In my NSManagedObject subclass I have an NSString ivar that splits up into an NSSet of entities. I'd like to be able to set the string and during a call to save, do the split, however, only setting the string will not trigger a dirty flag or a need to save.
You can implement the + (BOOL)contextShouldIgnoreUnmodeledPropertyChanges on you NSManagedObject subclass and return NO rather than the default (YES).
This should then cause the NSManagedObjectContext to be notified of changes properties even if they aren't represented by actual columns in the database.
I assume you mean "attribute" instead of "ivar". Your scheme of having a string being split into a set and then saving the set is perhaps debatable, but I guess that is not the issue here.
Why do you need to have the Managed Object marked as "dirty"? This is really not necessary. Just save it, dirty or not!
I do not know how you check the "dirtiness" of your managed object, but I assume you want this to trigger a save at a certain point. At that point you might just as well as check your own BOOL "dirtyFlag" which you can set as appropriate and keep available for checking.
It is always better to make these kinds of things explicit. Your code will become more readable and transparent.
I am trying to pull in a RSS feed and sort by pubDate. When I examine the 'updated' property, most of the time it is correct and give me a proper date but when I try to convert from a set to a sorted array, I get random results from the sort. I've tracked this down to the fact that when sort is doing it's comparesion, the property (which is an NSDate, see figure1) is coming in and being compared as a __nscfnumber! (also figure2)
Any help or idea would be much appreciated.
figure1
figure2
I assume the comparator block is just for diagnostic purposes? You don't actually need to supply a comparator for NSDate or any of the provided attribute type classes.
If the debugger is reporting that the date1 object is of a NSNumber-cluster class type, then somewhere a NSCFNumber instance is being assigned to to the updated attribute. The debugger ignores factors like a cast and instead simply asked the object what its class is. If the object says it is a NSCFNumber then it is, regardless of how the code treats it otherwise.
Why that happens, I can't say based on the code provided.
You might try logging the value and class of the updated attribute before you attempt the sort to see if it reports properly. I would also recommend decomposing the entire line. Nesting all those method calls will work of course but it is error prone and hard to debug.
Is it possible to make some conversion while mapping?
SchedulerStorage schedulerStorage =
schedulerControl1.Storage;
schedulerStorage.Appointments.Mappings.Start
= "StartTime";
For example I want to add one hour to Appointment.Start, but I don't want to change "StartTime" property get{} of my business object.
Generally, we did not consider such scenario of using the XtraScheduler when designed it. So, this feature is not supported. I can only suggest that you create a new field in the DataSource which will contain an updated value of the StartTime field and map the Start property to it....