Comparison of Systems for Mobile Application Development

disadvantages of the different approaches. Approaches with similarities in terms of the development technologies are grouped together (see figure 3.20).

Figure 3.20: Summary of features of all the systems discussed in section 3.1.2.

Integrated Development Environments (IDEs) and Application Frameworks Advantages. Integrated Development Environments combined with Application Frame-

works (e.g. Android Devt. Tools [Andc], Netbeans Mobility Pack [Net], XCode and Interface Builder [Appc],Project Ares [Pal], Qt Creator [QtM]) have the advantage of having the capability to createfully functional mobile applications (i.e. completely generated artifacts). Most IDEs also feature a complete set of tools such as debuggers, design tools, emulators, etc. that can assist developers in creating applications. Disadvantages. The feature-richness in the development environments however can also

pose as a disadvantage. It can take a while before the user can actually take advantage of the many features the environment has to offer and also affects the usability of such tools [BFH09b]. Also, programming skills and the willingness to learn how to use the different capabilities of these IDEs is a big necessity.

Visual Programming Tools and GUI Builders

Advantages. Systems that provide a visual programming environment such as Game- Salad [Gam]) and Graphical User Interface (GUI) Builders such as DroidDraw [Dro]

use thepower of images in order to create fully functional programs. These systems usually target a specific domain (e.g. GameSalad [Gam] for game applications) or a specific platform (e.g. DroidDraw [Dro] for Android applications), thus utilize graph- ical representations that are close to the domain or similar to the platform they are targeting. According to Petre [Pet95], such visual programming techniques are only effective when the specific representations support the conventions expected by the users of such tools, which means this representation poses as an advantage to users who are already familiar with the domain or platform.

Disadvantages. A disadvantage of using these approaches is that, the users should be able to understand what the purpose of such graphical representations are (i.e. it should not be ambiguous or interpreted differently by different users) [Pet95]. Another disadvantage specific to GUI Builders is that, it only allows a part of an application to be created, specifically the user interface. Application logic needs to be added by explicit programming. Visual Programming Environments on the other hand may provide fully-functional applications (e.g. GameSalad [Gam] for game creation). However, it requires very specific knowledge and uses domain-specific constructs that are not applicable for other domains or application types.

Authoring Tools

Advantages. Most authoring tools also make use of images to represent certain parts of the system. Just like visual programming approaches, authoring tools are also very specific to one type of domain. Just to cite some examples: M-Studio [PKCD02] usually targets story creators for creating applications for mobile cinema,Mobile Au- thor [VA05] is for teachers who want to create ITS systems,Mobile Bristol [HCM04] targets artists to create ubiquitous applications specifically mediascapes, and so on.

Targeting a specific domain however, can be seen as an advantage especially if the target users of these tools are novices. The design of these tools are usually sim- pler because it will contain a limited number of components specific to one type of domain than those that support development for general purpose applications. An- other advantage of the systems mentioned is that they take usability into account

when designing and creating the authoring tools. For the examples mentioned, us- ability evaluations were usually carried out in order to refine their designs and allow non-technical users to easily use them.

Disadvantages. Most authoring tools however have the disadvantage of not being flexible enough to be extended to other domains, such as the example systems cited in the previous section. Some approaches provide some framework to extend the capabili- ties of the tools, but still on one specific type of domain. Another disadvantage of some of tools is that the user of the authoring tool still needs to coordinate with programmers/technical staff in order to create the fully functional applications (e.g.

The MOPS Authoring Tool [BRW07] still needs developers in order carry out the final deployment).

Model-Driven Approaches

Advantages. The model-driven approaches we have seen in the examples so far varies in terms of the types of users they target and the tools they provide. One com- mon denominator between the different approaches is the use of models as primary artifacts in the development of an application. These models have their formal defi- nition in order to run automatic code generation tools to transform the models into code [SVC06]. The ModelBaker for example is created in order to assist users who know a lot about web development in the rapid development of web applications through modeling. The MetaEdit+ Workbench [Meta] on the other hand targets two types of users, the expert (i.e. developers, modelers) who creates the model- ing tools using the workbench, and the novice who uses the modeling tools created by the expert. An advantage of these modeling approaches is the use of formal models and standardized technologies (e.g. System from Dunkel et al. [DB07], SMS Project [BMSBM07]). Also, the ability to transform models to different software artifacts for different platforms is another advantage [KWB03].

Disadvantages. A disadvantage observed from the different model-driven approaches is that, they do not seem to take the end-user into account when designing the tools. The system from Dunkel et al. [DB07] for example uses a UML modeling tool for mod- eling the system and other separate tools for code generation. Dunkel et al. [DB07] even emphasized in their conclusion that "most of the UML modeling tools do not satisfactorily support meta-modeling and the code generating tools are still propri- etary and not yet stable". The approach is still quite fragmented in a way. Also, knowledge about UML constructs is a must for modeling the applications. TheMod- elBaker [Mod] that also claims ease-of-use still provides a complex interface in a way that one must know the MVC design pattern, database constructs and web-specific constructs in order to be able to create a model. Since the target users of this system are people with experience in web development, the design of the interface should work for them. However, in terms of suitability for other types of users particularly non-technical ones, this is not a very effective design.