It uses DataparkSearch's RESTful interface. At first, the idea was to use JSON format for data interchange, but it turned out native JSON parser works slowly in Android. As other parsers were not considered to be included into this project, we created a special search template (strings.htm) which sends "pre-cooked" data to Android client.
Now the main bottleneck is the data interchange itself. Perhaps I need to implement data compression in the RESTful API of DataparkSearch.