PowerBuilder to Java Web Based Re-Model process covers

 

Application functionality

Database Design (if required)

Data Migration (if required)

 

Approach

 

Requirements Engineering – The application functional requirements are documented through source code analysis, business rule reverse engineering, and use case extraction

Re-design – The application is designed in the new platform

Data Model – Model the database in the new platform (if required)

Develop – The application functionality is coded in the new platform

Data Migration – Existing data from the legacy database is migrated into the new data model (if required)

UAT

Deploy

 

Pros
PowerBuilder to Java Web Based Conversion

 

Technical and functional uplift

Error handling & security

Maintainability

True web based (MVC, SOA)

No refactoring is necessary

 

Cons
PowerBuilder to Java Web Based Conversion

 

Not a replication - it is a new app

Upfront heavy requirements and design phases

Higher risk

Testing

Not fully automated

Higher degree of end user involvement

 

Suited when

 

Maintenance & Testing staff are not available or have limited knowledge of the original code

Poorly documented or documentation not up to date

Functional or technical uplift is required

 

Issues ( Design & Development)
PowerBuilder to Java Web Based Conversion

• In PB the front end has business logic embedded with presentation logic. Which needs to be separated in Java web based.
• UI logic and navigation does not map one to one to web, so the business intent is needed so as to preserve functionality.
• Ensuring all business rules and logic are captured in the new model.
• In PB the front end has business logic embedded with presentation logic. Which needs to be separated in Java web based.
• Moving to a 3-tier design from a 2-tier design.
• There are many objects in PB that do not exist in java such as datawindow.
• Client server navigation is not implementable as-is on web
• Other web limitations such as timeouts, session, etc.
• Despite the best effort in design not all coding situations can be considered.
• UI behavior of web based applications is different than client server.
• UI performance of web based applications is slower than client server.

 

Solution (Design & Development)
PowerBuilder to Java Web Based Conversion

• VSI BAs will work with IT and business teams to develop understanding of the application and screen usage.- the interaction would be minimal
• Documentation tools such as PBDoc and Code Visual can be used to reverse engineer the application code and map out the business logic.
• At this time functional enhancements, such as new and enhanced features can be considered.
• All the findings will be documented in a requirements document, for review and approval.
• VSI uses a number of in-house developed components and frameworks to make the mapping of client server to web easier.
• Review of the code documentation, as well as the code to refactor the object model of PB to Java
• Refactoring of the code behind the datawindow events, button events, window events and NVOs to 3-tier.
• Segregate validations into server side and client side. Server side depend on data, whereas client side are static.
• Most NVOs can be converted with minimal change, other objects will be re-factored mapped to the final design model.
• One of the critical decisions to make is the use of session, which will depend on the usage of NVOs and user objects.
• Use of the JSF framework closes the gap between PB event model and web based request model UI
• Large table/grid operations will need to be paginated.
• Large update operations will be made multi-threaded and moved to background.
• The design will be documented and presented for review and approval.
• VSI developers will review the existing code in PB while developing the revised code in Java.
• The original code will be re-designed based on the new design and documented.
• When possible AJAX calls will be used to increase the interactive and responsiveness of the UI.
• Operations on large datasets as well as complex queries may be moved to stored procedures in order to reduce the load on the application server.
• For large applications the development will be carried out in phases in order to keep the project manageable.

 

PowerBuilder Re-Modeling - Deployment
PowerBuilder to Java Web Based Conversion

Test & Tune – Once developed the new application is first tested by the end users for acceptability and then fine tuned for performance.

 

Data Migration – Data mappings and ETL programs are developed to migrate the data from the source to the target. A test run of the data migration is first carried out before the final migration into the new platform at the time of deployment.

 

Deployment – Finally the new application is deployed in the new environment.

 

Web Architecture Diagram
PowerBuilder to Java Web Based Conversion

 

 

 

 

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