Tools and resources

simCHET, simulated Computer Human Engagement Tool, was designed with a view to reproducing the interaction observed in the JavaStudio design process. It was immediately recognized that it would be impossible, and even undesirable, to mimic all aspects of JavaStudio.

In practical terms, simCHET is a relatively simple tool. It is similar to the CARD/PICTIVE tools employed by Muller et al. [9]. This approach was originally pioneered by Beck and Cunningham [3] in support of teaching object-oriented thinking. It involves the use of index cards or note paper to represent the components or objects within the system. Spatial organization of the cards reflects the relationships between the objects and additional indicators and/or text provides the detailed functionality. Design can then take place with the alteration of either or both the cards themselves and their organization.

  

Figure 6: A rotation bean with icon and descriptors

In the case of simCHET, the tool is composed of six basic elements:

• page-sized PostIt notes - component icons representing JavaBeans;
• drawable paper surface - a large area for assembling the icons and then adding relational notation and indicators;
• coloured pens - for notation; different colours depicting various processes and mechanisms;
• smaller PostIt Notes - descriptors indicating the icon functions and dynamics (e.g. what happens when);
• yarn/string of various lengths - the connections between the various components;
• very small PostIt Notes - instantiation tokens used to show specific values or data blocks as they are passed around the system.

Interestingly, the essential feature seemed to be the descriptors; in initial tests both with adults and students, it was found that it played an essential role in enabling correct design procedure (Figure 6 shows an example of a ``rotation'' bean with its icon and descriptor). This is not surprising since the descriptors peg the functionality of each JavaBean. Similar features are found in most scenario-based tools of this sort [3,9] as it provides the critical information about the nature of the objects.

In order to understand how simCHET is both similar to and distinct from Java Studio, both can be characterized by what they offer the user in support of the construction of Beans-based tools. Java Studio can be described as having an explicit visual interface, dual representations of the function and the form of the design and computer-mediated manipulation of components.

simCHET on the other hand has a single multi-dimensional, multi-modal representation, notional icons and functionalities, unmediated manipulation of the relationships and reliance on user compliance with rules of interaction. Figure 7 shows an example of a full simCHET-designed applet. Note the similarities to (and differences with) the JavaStudio design for the same applet shown in Figure 5.

  

Figure 7: A full simCHET-designed applet