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Nowadays, the Web 2.0 has significantly changed the way users interact with the web. The nature of Web 2.0 requires the growth of Rich Internet Application (RIA) technologies, such as Flash and Ajax. RIA technologies allow richer, faster and more interactive experiences. It breaks the old click-and-wait user experience mode. Instead, by only changing updated information without refreshing the entire page, RIA makes the web-based application feels more like a desktop application (Hewlett-Packard, 2007).
Adobe Flash is a multimedia platform for creating interactive and animated web sites. Flash movies and games are commonly integrated into web pages as components for entertainment or advertisement. For example, there are many Flash games in Facebook (n.d.). Flash contains ActionScript 3.0 (AS3) which is an object-oriented scripting language based on ECMAScript. To view these Flash movies and to execute these ActionScript files, browsers require the Adobe Flash Player add-on. Adobe (2009) claims that about 99% of Internet-enabled desktops have the Adobe Flash Player (10-current version) installed. Many smartphones including Android, BlackBerry, Palm webOS devices, etc now also support Flash Player 10.
The performance of Flash applications, especially in mobile devices, directly influences the user’s experience. Speed is one of the most important requirements for mobile devices’ users (Buyukozkan, 2009). The user’s experience of Flash applications is partially determined by the download time and execution time of Flash files. Download time depends on the size of the Flash file and the connection speed to Internet. The file size can be reduced through the compression of the file. Execution time relies on the processing power of the client machine and the performance of the ActionScript code. Although reducing Flash files’ size is helpful, it is not the key point; writing faster and more efficient ActionScript code is the most useful way to improve the user’s experience.
The quality of Flash code is highly dependent on the developers; however, Flash programmers often “have backgrounds in music, art, business, philosophy, or just about anything other than programming. This diversity results in awesome creativity and content” (Skinner, 2007), but imposes technical challenges. In addition, the tight schedule of a project tends to result in developers concentrating on “getting the functionality correct” (Skinner, 2007), while ignoring non-functional characteristics such as efficiency.
This paper presents a “refactoring for efficiency” Flash support system, ART (ActionScript Refactoring Tool), to help AS3 programmers produce more efficient code by automatically transforming their ActionScript code. This paper is organized as follows: First we discusse the efficiency problems in traditional web applications and RIAs, and related works. Then we introduce the Flash execution model. Next we analyze possible strategies for improving efficiency in Flash applications and then describe the design of ART. Finally we provide an evaluation of our system and conclude the article.