Oracle SOA Re-Hosting Based Modernization

Re-Hosting Based Modernization

Evolving from the core re hosting approach and leveraging flexible, rules driven automated conversion tools, this approach goes beyond re hosting to a functionally equivalent application. Instead of a pure shift of COBOL code to a target system without any changes to the original code, some of the automated tooling used by Oracle migration partners to re host applications and data also enables automated re engineering and SOA integration during or following migration. For example, Metaware Refine workbench has been used to

• Automatically migrate COBOL CICS applications to COBOL Tuxedo applications.

  
  

• Convert PL/I applications running under IMS TM to C/C++ applications under Tuxedo.

  
  

• Identify and remove code duplication and dead code, re-documenting flows and dependencies derived from actual code analysis.

  
  

• Migrate VSAM data and COBOL copybooks describing the data schema to Oracle DB DDLs and automatically change related data access code in the application.

  
  

• Migrate DB2 to Oracle DB, making appropriate adjustments for data type differences, changing exception handling based on differences in return codes, and converting stored procedures from DB2 to Oracle.

  
  

• Perform data cleansing, field extensions, column merges and other data schema changes automatically synchronized across data and data access code.

  
  

• Migrate non-relational data to Oracle DB to provide broader access from applications on distributed systems.

  
  

• Convert 3270/BMS interface to Web UI using JSP/HTML, enabling modifications and flow optimization in original legacy UI.

  
  

• Adapt batch to transactional environment to shorten batch windows.

  
  

APA tools for automated business rule discovery can also be used to help identify well defined business services and use Oracle Tuxedo's SOA framework to expose these COBOL services as first class citizens of an enterprise SOA. This approach can also be applied to PL/I applications automatically migrated to C/C++ and hosted in Tuxedo containers. The bulk of the re-hosted code remains unchanged, but certain key service elements that represent valuable re-use opportunities are exposed as Web Services or ESB business services. This approach protects investment in the business logic of the legacy applications by enabling COBOL components to be extended to SOA using native Web Services gateway, ESB integration, MQ integration, and so on of the Oracle Tuxedo a modern TP/Application Server platform for COBOL, C, and C++.

Thus, we gain a huge advantage by having a well structured, SOA-enabled architecture on a new platform that was delivered with a high degree of automation. Using a proven application platform with built-in SOA capabilities, including native Web Services support, ESB transport, transparent J2EE integration, and integration with meta-data repository for full services lifecycle governance, makes this a low-risk approach. It also helps to address some of the key considerations in SOA integration table above. With this approach we have the ability to extend and integrate the legacy environment easier than a pure re-host, while benefitting from the automation that ensures high speed of delivery and low risk that is comparable to a black-box re-hosting.

The other aspect of this process is identifying components that will benefit from re-architecture usually code with low maintainability index or code requiring significant changes to meet new business needs and using re-architecture techniques to re-cast it as a new components, such as business process, declarative rules in a business engine, or re-coded J2EE components. The key is to ensure that the re-architected components remain transparently integrated with the bulk of the re-hosted code, so that the COBOL or C/C++ code out-side of the selected components doesn't have to be changed. With Oracle Tuxedo this is done via transparent bi-directional support for Web Services (using Oracle SALT) and J2EE integration (using WebLogic-Tuxedo Connector). The key guidelines listed for business rules-extraction and model mining apply to the components selected for re-architecture.

Re-hosting based modernization is sometimes referred to as Re-host++. This term highlights its roots in re-hosting applications to a compatible technology stack together with the broad range of re-engineering, SOA integration, and re-architecting options it enables. This unique methodology is supported by a combination of an extensible COBOL, C, and C++ application platform Oracle Tuxedo, with flexible, rules-driven automated conversion tools from Oracle's modernization partners.