* populate data structures for rendering
*/
public HeatmapData getData() {
// preliminary setup
OfflineTimeHandler time_offline;
TimeHandler time_online;
long start, end, min, max;
if (offline_use) {
time_offline = new OfflineTimeHandler(param_map, this.timezone);
start = time_offline.getStartTime();
end = time_offline.getEndTime();
} else {
time_online = new TimeHandler(this.request, this.timezone);
start = time_online.getStartTime();
end = time_online.getEndTime();
}
DatabaseWriter dbw = new DatabaseWriter(this.cluster);
// setup query