IMS COBOL to Java Modernization (Optional C# Support)

Refactoring COBOL IMS DB to SQL and Object-Relational Java

COBOL programs access IMS databases using CALL 'CBLTDLI' statements. Because of the IMS design, much of the critical information is only available at runtime and encoded in runtime parameters, making it difficult for developers to understand a program's logic through simple visual inspection.

SoftwareMining utilities convert IMS hierarchical structures, defined in DBDGEN macros, into SQL tables while maintaining all parent-child relationships. The tool also generates a set of Object-Relational data access classes that mirror the same hierarchy. For example, opening a PARENT class (segment) automatically opens all CHILD classes (segments) linked by the referenced PCB.

Using the information defined in program-specific PCBs, the system dynamically builds the relationships required by each program. This allows the translated Java application to determine, at runtime, which SQL tables and relationships should be accessed.

An IMS call emulation layer operates above the Object-Relational classes and SQL tables to preserve original IMS DLI behavior. For instance, the first GN (Get Next) call returns the PARENT data, while the next GN call retrieves data from the CHILD segments.

One major advantage of SoftwareMining's architecture is its ability to report, at runtime, the exact SQL statements generated and executed for each IMS DB call. This transparency allows developers to see which database actions are performed and, in later project phases, replace them with optimized SQL for improved performance and maintainability.

This approach enables a two-phase modernization strategy:

• Phase 1: Automated translation, data migration, testing, and production deployment.
• Phase 2: Incremental refactoring of IMS-DC (CBLTDLI) statements to improve readability and performance.

Refactoring COBOL IMS DC Online Applications

IMS DC is used in online applications to manage screens defined in MFS format, typically displayed on IBM 3270 terminals. SoftwareMining's modernization approach converts MFS screen definitions into JSP or XHTML (HTML) formats, making them accessible through standard web browsers.

The initial web interface replicates the look and behavior of the original 3270 screens. Over time, it can be enhanced with modern UI features such as checkboxes, radio buttons, and drop-down lists to improve usability and align with current web standards.