This method was internal and is now hidden.
You can use the following method to get information about a cell under certain position:
var cell = dps.cells.findByPixels(120, 1)[0];
var start = cell.start;
var end = cell.end;
var resource = cell.resource; // id
It is available in Java since build 7.5.8331 (see the sandbox at http://java.daypilot.org/sandbox/).
This is an extension of the existing .cells API which allows you to read and update the cells:
dps.cells.findXy(0,0).html("first cell");
dps.cells.find("2013-10-07", "A").addClass("highlighted");