How to control the property name of a serialised object using Apex

Question

BACKGROUND

I need to generate the below JSON data:

JSON

{
  "Type": "ACCPAYCREDIT",
  "Status": "AUTHORISED",
  "Contact": { 
    "ContactID": "eaa28f49-6028-4b6e-bb12-d8f6278073fc" 
  },
  "Date": "2009-03-29",
  "LineAmountTypes": "Exclusive",
  "LineItems": [
    {
      "Description": "MacBook - White",
      "Quantity": 1.0000,
      "UnitAmount": 1995.00,
      "AccountCode": "720"
    }
  ]
}

So I've created the below Apex class

Apex Class

public class XeroCreditNote {

    public String Type;
    public String Status;
    public XeroContact Contact;
    public Date Date;  // <------- THIS LINE ERRORS
    public String LineAmountTypes;

    public LineItem[] LineItems;

    public class LineItem {

        public String Description;
        public Integer Quantity;
        public Decimal UnitAmount;
        public String AccountCode;

    }
}

But the line public Date Date; give me an error:

Identifier name is reserved: Date

The class is serialsied like this:

return (List<XeroCreditNote>) JSON.deserialize(jsonSerialized, List<XeroCreditNote>.class);

QUESTION

I would like to be able to set the Apex property name to something that isn't reserved but make sure the correct property name is used when the object is serialized.

How can I do this with Apex?

Answer 1

If you want to use reserved keywords as keys in your JSON payload, the simplest solution is to just use Map<String, Object> rather than a concrete type.

system.debug(JSON.serialize(new Map<String, Object>{
    'Date' => Date.today()
}));

The only other alternative I know of is string replacement, which I would be leery of implementing, but should also be viable. I would be careful to search for "myKey": rather than just myKey when you do any such replacement.

Answer 2

The simplest approach for JSON output is the very hacky:

public class XeroCreditNote {
    ...
    public Date myVeryUniquePrefixDate;
    ..
}

and a replace of myVeryUniquePrefix with nothing in the JSON string.