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Delivering Code Reusability for Developer Productivity

The Clarion metabases store the metadata (business logic and database schema), application (application logic) and user interface layers for all projects referencing corporate data. An extensible code generation system generates full featured applications from the descriptions stored in the repositories.

The Data Dictionary

In addition to storing a description of the database schema and business rules, the Clarion Data Dictionary stores default options for type of control associated with a specific column from the database for use on a Form or Report. All of your applications that use that Dictionary can make use of these defaults, or the programmer can override any of them in the visual design tools.

The Template Registry

The Template Registry stores the reusable application logic that is applied to the specific project. The Templates that ship with Clarion have built-in capability to perform almost all common database requirements. There are also third party templates available from other vendors for sale. And then there are the templates that businesses develop on their own for use in house.

Clarion Code Reusability

Business developers may generate many applications from the same metadata, e.g., an application to access the Human Resources tables, and another to access the Accounts Receivables tables. The generated applications will have the uniform look and feel that the developer specifies, providing a corporate standard and making it easier for users to learn new applications.

The illustration below pictures the default application paradigm: threaded browses allow the end user to locate a record by typing a few characters. Double-clicking the record displays an edit window. If there are child records in another table, they appear in a list contained on a tab in the edit window. Double clicking one of the child records displays an edit window, and so on.

The code generator relies on "templates" to store the application logic. A business' master programmers can create their own templates, in effect flawlessly cloning their expertise to all subsequent projects produced by entry level programmers, even ones that reference different data or even different databases. This creates a "factory floor" production model for software, and is most useful for businesses that require many look-alike applications for different tasks, whose only commonality is that they view, edit and report corporate data.

The level of options stored in the Data Dictionary, and the amount of flexible, extensible application logic stored in the template registry distinguish the Clarion development model from any other.

The concept behind Clarion development is to store in the Data Dictionary a description of the database plus formatting and behavioral options for the controls that refer to specific data elements. The developer can run a wizard which asks what tables within the dictionary to design an application for. It creates a remarkably full application. From there, the developer walks the Application Tree (below), which is a hierarchical view of the application, and enhances its functionality by applying additional templates.

The metabases enhance developer productivity by making as many application behaviors as possible available through lists, helping the developer to fulfill as high a percentage of the programming task as possible by selecting, rather than by coding, and delivering true code reusability.

Developers may also further customize the generated applications further with a rich business oriented language that programmers say is remarkably easy to learn, and for which many training options exist. In effect, developers may add in functionality for anything the templates don't already provide. Additionally, Clarion provides an object framework specifically for database and business oriented functions. Clarion also makes it very easy to access external libraries written in any language.

Because the templates generate an overwhelming majority of the code necessary for most projects (they feature important business functions that other development environments lack), programmers concentrate on application logic specific to your industry, and perhaps as importantly, are only required to learn one application methodology that applies to many applications.

The list below shows the functions available through the template repository in Clarion Enterprise Edition:

Threaded, multi-user aware data grid
Multi-user aware update form
Multiple document interface application window including threading and menu
Single document interface application window
Process user defined code statements for each record in a table, sequentially
Generic report with print preview
Call a function in an external library
Introductory screen
Display text
Display read-only Form, with no update allowed
Generic window
Print a text file
Search a text file
Implement fuzzy matching in database search
Print a single record in data grid
Query by Example
Toolbar navigation buttons
Cancel an operation
Close the current window
Locate a file name
Change the source for a displayed image
Search for a record based on a lookup value
Create a dropdown list or combo box from a table
Insert an OCX control
Pause the current process
Hierarchical data display in tree control
Date and time stamps for report
Display and edit Rich Text Format file
Save current update, keep window open
Validate items in selected controls vs. business rules
Popup menu
Implement drag 'n drop
HTML help file
Report Operating System version
Create new thread
Lookup a record in a non-related table
Create flexible layout to allow resizing of window and its controls
Display date and time in the current window
Database auditing
Create a progress control
VCR form controls
Run an external command

All the actions above are available by applying Clarion templates, which are managed in the template registry:

The Data Dictionary

The Template Registry

Cloning Master Programmers' Code

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