Delft University of Technology
Faculty Mechanical, Maritime and Materials Engineering
Transport Technology

M.R. Martens Visual activities for Delphi using TOMAS
Computer program, Report 2004.TL.6854, Transport Engineering and Logistics.

TOMAS is a library for Borland's Delphi providing non-graphical elements that can be used to simulate time related cases. However modern Integrated Development Environments like Delphi give the advantage to quickly develop graphical applications. The goal is to give TOMAS this same advantage.

This means that if the user wants to add a new simulation element (called a "class" in Delphi) the source-code of this class must be automatically generated and the class added to the palette of Delphi. The tasks for the user are to place instances of simulation elements on the form, assigning properties and relations with other elements, and implement the Process method to define simulation characteristics.

The source-code generator will be an external program or a program within Delphi that communicates with the interface of Delphi. An experiment is started to show how the source-code looks like generally and how complex it will be to automatically generate this code.

This experiment uses the activity class. An activity is an element in a certain tree of activities (called a project) that takes some time to complete. After that the next activity in the tree is started.

A Delphi package is made to add the functionality of activities to a Delphi application. Design and simulation of the activity network work the same way as a standard application, i.e. the project is setup during design-time and simulated during runtime.

The development of the graphical activity class showed that in general the source-code that has to be generated automatically consists of registration statements to let Delphi know new classes are present, a visual Delphi class, a non-visual TOMAS class and forms to interact with the user to change property values. As for the complexity of the source-code, two major problems were encountered.

First, to generate source-code for both a visual and a non-visual class that interact with each other is very hard, it is highly advisable to develop a general graphical TOMAS class so the two classes will be combined to one class.

Secondly, problems were encountered with property values that are objects (not integers, strings, etc.). The generation of forms so the user can edit such a property as well the generation of source-code to store object property values in form-files is very complex. Routines should be developed to take care of these problems with object property values in a general matter.

A final problem is that adding new visual classes to Delphi is not very user-friendly, because a change in the package that provides these classes requires a restart of Delphi. So while these three problems are not solved it is not recommended to proceed further with the plan for a complete visual TOMAS. However, the visual activity classes work rather well and it is recommended to develop more graphical elements to gain more knowledge of a one day complete visual TOMAS.

Reports on Transport Engineering and Logistics (in Dutch)
Modified: 2004.05.12; , TU Delft / 3mE / TT / LT.