What is the least bad way of knowing the type of a key from Json file

Question

in our app we have a Json file that contains several properties used for menu configuration. One of the keys should tell us if a menu item should be displayed. The thing is that the value for this key, can be an int but written as String "0" or "1", a Boolean written as String "true", "false", or an URL. So depending on the item, one of these 3 'magic' values tell us if a specific item should be displayed or not.

My question is, what is the best way or the elegant way of knowing the type of this value? We need to know the type for different handling.

At first I created a method for checking if the value is of Boolean type.

return value.equals(true.toString()) || value.equals(false. toString()));

The same, I should create a method if it is int, but for checking if it's a URL is a bit tricky.

So because I didn't find this approach very elegant and readable, I decided to add the type of this 'magic' key in the Json file: For Boolean type I added:

"myKeyType": "boolean"

And so on for the other 2. So I would like to know if adding a type property to Json file is a good idea, if it's Json responsibility to tell us the type, or is there a better way to do this?

EDIT: I can't change the type of data I receive, so I have to deal with the scenario I described. In this case, which of the 2 solutions I tried is more elegant? The first one, or the 2nd one with the extra key?

Thanks

Answer 1

Sorry to say there is no elegant way of this messy design.

If you had some control it would be better to split these magic values into a plain array where each propertiy is of one type.

regarding your suggestion of "mykeytype":"boolean" some json libraries support this out of the box. Example json.net you can set typenamehandling=auto and it will add an extra field with type info when ever runtime type does not match static type.

I'm unavare if any libraries for Android support polymorphism but this question may be a place to start:

Answer 2

You can really have anything you want in the JSON response as long as you define it as a standard and adhere to it. Naturally, you then need to parse the standardized JSON response in your code according to the presented rules.

However, I don't like the current design and would have redesigned the JSON response (from your recent comment it seems you have control over the structure).

The format could be

{
    "shouldBeDisplayed": true,
    "url": "http://myurl.com"
}

for a truthy case and either of the following formats when it should not be displayed:

{
    "shouldBeDisplayed": false,
    "url": null
}

{
    "shouldBeDisplayed": false
}

For a boolean variable, it would be nice if you returned nothing but true and false, even though some values may be considered truthy and falsy.

Answer 3

Since you mention you have control over the json with Java (in other words at the backend). I always favor shielding a front-end of these sort of proprietary concerns. Let Java create a json file that will fit like a glove, normalize the data before sending it across the wire.