1 research outputs found
Search-based Tier Assignment for Optimising Offline Availability in Multi-tier Web Applications
Web programmers are often faced with several challenges in the development
process of modern, rich internet applications. Technologies for the different
tiers of the application have to be selected: a server-side language, a
combination of JavaScript, HTML and CSS for the client, and a database
technology. Meeting the expectations of contemporary web applications requires
even more effort from the developer: many state of the art libraries must be
mastered and glued together. This leads to an impedance mismatch problem
between the different technologies and it is up to the programmer to align them
manually. Multi-tier or tierless programming is a web programming paradigm that
provides one language for the different tiers of the web application, allowing
the programmer to focus on the actual program logic instead of the accidental
complexity that comes from combining several technologies. While current
tierless approaches therefore relieve the burden of having to combine different
technologies into one application, the distribution of the code is explicitly
tied into the program. Certain distribution decisions have an impact on
crosscutting concerns such as information security or offline availability.
Moreover, adapting the programs such that the application complies better with
these concerns often leads to code tangling, rendering the program more
difficult to understand and maintain. We introduce an approach to multi-tier
programming where the tierless code is decoupled from the tier specification.
The developer implements the web application in terms of slices and an external
specification that assigns the slices to tiers. A recommender system completes
the picture for those slices that do not have a fixed placement and proposes
slice refinements as well. This recommender system tries to optimise the tier
specification with respect to one or more crosscutting concerns. This is in
contrast with current cutting edge solutions that hide distribution decisions
from the programmer. In this paper we show that slices, together with a
recommender system, enable the developer to experiment with different
placements of slices, until the distribution of the code satisfies the
programmer's needs. We present a search-based recommender system that maximises
the offline availability of a web application and a concrete implementation of
these concepts in the tier-splitting tool Stip.js