VistA is written in Mumps. 

  • Is the vista smart container a complete implementation of vista or just a subset of vista?
We only implemented a part of the Smart container spec as a proof of concept, so it is not complete and it is out of date.
  • Does vista have a API? If so, in which languages? Is there Java support? I would prefer having a direct API access and then writing my own WS for the particular response schema I need to integrate with the robot.
The primary way that people interface with it is through RPCs... Java and Delphi clients are common. Javascript is also widely used. What I showed you was a way of interfacing via a web service. The web service code is in Mumps.
  • You mentioned there is a REST WS. Is there a SOAP WS?
There is no "standard" Rest or Soap support in VistA... i and others have written our own for projects we have that need them
  • If I download dEWDrop, would I be able to play with vista-smart container directly without any other installs/configurations?
dEWDrop, which is the the VM i recommended to you, is a complete installation of VistA, set up for both a hospital and a clinic, and includes test patients. It is a copy of what was used by WorldVistA to certify for Meaningful Use Stage 1, if that has any meaning to you. It has various additions to it, including the Smart Container code.
  • Is there any documentation which can explain the data-model returned from vista? For example for the medication data returned in the REST call, is there a reference to interpret it.
  • If there is an element of data missing from vista's data-model that I need, how can I add it? Do it need to add a table? Do I have to use MUMPS or is there any easier way?
You can read about VistA and the "data model" in documents on this site:

Adding new elements to the VistA patient record ( the "data model" ) is not an easy task and is done in Mumps usually by people with years of experience... However, it's not that hard to make a new file to put your robot's information into and get that back out again... it can be linked to the patient record with a fileman pointer...