Apex JSON parsing error - json

Question

I am getting the following error in my code:
System.JSONException null Don't know the type of the Apex object to
deserialize at [line:1, column:1] 11 (System Code)
Class.FactorLab.FactorLabWebservices.RetrieveUsersFromFactorLab: line
60, column 1 Class.FactorLab.PullUsers.execute: line 61, column 1
Here is the code in question:
public static List<FactorLabPullUser> RetrieveUsersFromFactorLab(List<String> ids){
HttpRequest req = getHttpRequest(baseUrl + '/ws/sfdc/people/retrieve', 'POST');
req.setBody(JSON.serialize(ids));
req.setHeader('Content-Type', 'application/json');
if(Test.isRunningTest()){
return null;
}
HttpResponse res = sendRequest(req);
// This is the line with the error
List<FactorLabPullUser> flusers = (List<FactorLabPullUser>)JSON.deserialize(res.getBody(), Type.forname('List<FactorLabPullUser>'));
return flusers;
}
I'm sure that it's receiving valid JSON, but I'm not sure the exact JSON it's receiving when it gets this error. It could simply get an empty array:
[]
It could also get something like this:
[ { "SFDCStatus" : "RETRIEVED",
"address" : "123 Fake St.",
"addressLine1" : "Address1",
"addressLine2" : "Address2",
"city" : "San Francisco",
"companyName" : "Big Cheese, Inc.",
"deleted" : false,
"email" : "james.willard#fake.com",
"firstName" : "James",
"hireDate" : "2000-04-15T00:00:00Z",
"id" : 39,
"lastName" : "Willard",
"lastUpdated" : "2011-11-23T05:44:03Z",
"myersBriggs" : "SFDC",
"name" : "James Willard",
"phone" : "415-555-1212",
"position" : "Big Chief",
"regions" : [ { "deleted" : false,
"id" : 445,
"name" : "Mountain"
} ],
"state" : "CA",
"yearsExp" : 20.0,
"zip" : "94131"
},
{ "SFDCStatus" : "RETRIEVED",
"deleted" : false,
"firstName" : "Daniel",
"id" : 40,
"lastName" : "Adams",
"lastUpdated" : "2011-11-23T05:44:03Z",
"name" : "Daniel Adams"
}
]
Any ideas? Someone told me this was a Salesforce.com bug, but it seems like even if that were true, there must be a workaround.

Answer 1

Looks like you may not be casting properly. I haven't played around with the serialize/deserialize native JSON much yet and have preferred to do my own parsing/persisting. But your line causing the error looks suspicious:
List<FactorLabPullUser> flusers = (List<FactorLabPullUser>)JSON.deserialize(res.getBody(), Type.forname('List<FactorLabPullUser>'));
I think it should look like the following:
List<FactorLabPullUser> flusers = (List<FactorLabPullUser>)JSON.deserialize(res.getBody(), List<FactorLabPullUser>.class);

Answer 2

I can't see for sure from your code snippit but if the FactorLabPullUser class is an inner class you will need to fully qualify it for Type.forName() to work.
I would expect to see something like this:
List<FactorLabPullUser> flusers = (List<FactorLabPullUser>)JSON.deserialize(res.getBody(), Type.forname('List<Outerclass.FactorLabPullUser>'));
I think that the bug you mention is to do with the use of the .class method - I have noticed this not always return a valid Type.