Simon,
So far what I have seen and done with JSON has utterly underwhelmed me. And I have deployed two systems that use it now.
I tend to take the view that JSON is for people who just push buttons in tooling and have no idea what is really going on under the hood. Nothing wrong with that of course - so long as the mess is inside their own ecosystems and networks - but the onus is then on other folks to sort out the mess they are all creating out there when content escapes out into the broader world.
That's been my experience - where someone dumps off a ton of JSON formatted data - and then we have to reverse engineer it - and frankly its a nightmare. I'm sat here thinking - OMG - I've just been thrown back fifteen years to where we used to be with EDI - exactly the same painful and time consuming pack drill. And then people use back doors and shoe horning content into fields - just like the infamous Z segments in EDI - because they don't want to add new fields or change the layout because they will break all the downstream systems then.
Adults should really be using XML for extended information exchanges, and especially for country, state or international standards. You may be able to get away with JSON for something really trivial and local - such as town bus route numbers, bus stops and times of the next bus - as an open data feed - but for anything with real substance and content depth and relationships and semantics - you are IMHO going to want what XML provides to handle that.
And especially if your requirements include access policy - which is a big deal now for government - (e.g. who is permitted to see data, what parts are applicable in their context?) - then rule driven access control - works seamlessly in XML. Now I'm sure you can show how that can be still be done in JSON - but I for one would not want to maintain that code - when the equivalent I have already in XML is elegant clean and simple.
I am very happy to embrace new stuff - and I'm usually the first one foisting new stuff on everyone - and listening to all the push back! But frankly for the uses and customer needs that are the mainstream in the world I deal with JSON looks to have only very limited functional plays.
But we are listening some - we have built JSON generation into our latest toolset - for those who want that option. I don't mind outputting it - if folks feel it makes their life easier - its a simple one liner call to a Java function library. But just don't expect me to want to consume too much JSON - because in my experience so far this has spelled nothing but headaches.
David
