is there any feasibility to invoke json in process design to generate the pdf though output service in workbench -Adobe Live Cycle

Hi,

I have created a process design that's generate the pdf by using outputService. To invoke the process I have to pass the input payload in the form of xml. But I have the database where all my user entered data stored in the form of json. So, we have a middle layer that convert the json to xml and then will call our AEM REST API. 
My question is that, is there any feasibility we can invoke the process by using json payload itself. I did not see any of document related on that. 
Can we create custom process that take input as json file to bind those json data to our xdp dynamic elements. If so, can you please guide me how to create the custom process in aem form on JEE.