· Jan 21, 2020

Converting an object from type %Library.DynamicObject to another type

I need to convert a JSON payload to a custom object type. Currently, I'm converting the JSON object to a %Library.DynamicObject object and need to proceed from here.

As of now, these are my options

                 1. Using an external library talked about in this link:

Downside: Could be buggy (as admitted by the creator) + some other design concerns brought up in its the discussion thread


2. Creating a new object of the desired class and then Iterating through the DynamicObject and populating the new object's fields.

Downside: Having to do this for each type of object individually rather than being able to generalize it (because of the need to instantiate new objects for swizzled objects)

Is there a standard way of doing this?

IRIS for UNIX (Apple Mac OS X for x86-64) 2019.4.0DS (Build 165U)

Discussion (4)1
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The example below works even in Caché:

#include %systemInclude n try{   $$$AddAllRoleTemporaryInTry   n $namespace   s $namespace="SAMPLES"      person=##class(Sample.Person).%OpenId(1)      ##class(%ZEN.Auxiliary.altJSONProvider).%WriteJSONStreamFromObject(.stream,person,,,$$$YES,"aeloq")   "json (string): ",stream.Read($$$MaxLocalLength),!!      ##class(%ZEN.Auxiliary.altJSONProvider).%ConvertJSONToObject(stream,"Sample.Person",.obj)   "obj.Home.Street: ",obj.Home.Street ; or d $system.OBJ.Dump(obj)    }catch(ex){   "Error "ex.DisplayString(),! }
Result: USER>^test json (string): {"Name":"Pascal,Martin F.","SSN":"502-68-5767","DOB":43307,"Home":{"Street":"9347 Franklin Drive","City":"Denver","State":"VA","Zip":66346},"Office":{"Street":"4897 Main Blvd","City":"Miami","State":"MO","Zip":60084},"Spouse":"","FavoriteColors":[],"Age":"60"} obj.Home.Street: 9347 Franklin Drive

Or use %JSON.Adaptor: Exporting and Importing

I'm not sure in what version %JSON.Adaptor was introduced, but if it's in your version, you can have the class modeling your object extend %JSON.Adaptor, which will give you access to the %JSONImport() method, which can de-serialize a JSON payload into an object.

One caveat to this is that I believe any serial objects referenced by the top-level object will also need to extend %JSON.Adaptor for the import to work properly.