Redvers Cobol XML Interface

The Redvers COBOL XML Interface gives COBOL applications fast efficient access to the world of XML and web services.  This off-the-shelf product is written in pure COBOL and requires just the coding of a COBOL record layout and CALL statement to generate or parse any well-formed XML document.

We’ve taken the unusual step of delivering our interface in the form of COBOL source code subroutines because we understand how important it is to have a solution that is easily integrated with existing applications, as well as one that provides maximum flexibility and efficiency.

The Redvers COBOL XML Interface operates at record level. This means that the interface builds all the necessary XML element structures when generating, and correctly interprets XML structures when parsing. This approach replaces complex element level application logic with a single CALL statement that passes the next logical record to/from the application.

The product is currently used by customers all over the world, running on AS400, UNIX, HP, CA-Realia, Siemens, Fujitsu, Micro Focus and of course IBM mainframe platforms. It is frequently used in Service Oriented Architecture (SOA) projects and to integrate XML messages on IBM’s MQ Series with core COBOL applications. It is also suitable for generating and parsing SWIFTNet messages and Single Euro Payments Area (SEPA) applications.

Download a PDF white paper on COBOL XML interfaces here...

How it Works

Before a COBOL application generates or parses XML, a COBOL Record Definition (CRD) must be coded, consisting of a working storage field definition for each field used by the application. This CRD is placed in the standard copybook library and a COPY/INCLUDE statement for the CRD is added to the application code for inclusion at compilation time.

At run time, the interface modules read the CRD source code from the copybook library in order to interpret the passed COBOL layout.

To generate XML, the COBOL application populates the CRD and passes it to the generation subroutine (RCCOBXML) which writes the XML document.

To parse XML, the COBOL application calls the parser subroutine (RCXMLCOB) which reads the XML document and returns the data in the CRD fields.

The batch generation/parsing process is illustrated below:

Technical Information

The product now operates at any of five levels:

• Batch level directly reads and writes XML documents of unlimited size to and from external files.
• Message level runs in batch mode but accepts and returns XML documents to/from linkage.
• CICS level runs under a CICS transaction holding XML documents in storage.
• Standalone level can run in batch or on-line modes as a logic only routine that requires no external data access (ideal for an Enterprise Service Bus in SOA environments).
• Superfast level is designed for high transaction throughput in large installations. This level can also run in batch or on-line modes.

To compare the different characteristics of each interface level, download a PDF comparison chart.

Each level consists of a pair of COBOL subroutines that generate or parse XML. Unlimited document sizes and element repetitions are handled by issuing multiple calls to these subroutines. This enables the interface to process complex XML documents without consuming large amounts of storage.

The programs are sold in source code form which permits changes to certain values that would otherwise be fixed. These values are known as User Maintained Variables (UMV). Examples of UMV’s are the PROGRAM-ID and external file names, which can be changed to comply with site standards or application requirements. Full details on all UMV’s can be found in the product user guides.

In order to protect both clients and authors from unauthorized code changes, the subroutine source code is cloaked using the Redvers Cloaking Device. This process makes no logical difference to the code but renders it unintelligible to humans.

The COBOL Record Definition (CRD) can be coded to generate/parse any XML tag names, attributes, namespaces, SOAP and mixed content elements. The appearance of data within XML elements is controlled using standard COBOL picture editing symbols.

The generated well-formed XML standalone document conforms to the World Wide Web Consortium (W3C) Extensible Mark-up Language (XML) 1.0 (2nd Edition) definition.

XML generation rate is 1.79 kilobytes per millisecond; parsing rate is 1.35 kilobytes per millisecond (running on an IBM xSeries 500 MHz Power3 processor). Maximum document size is 99,999,999 bytes (except batch level which has no limit).

Sample Output

An example of XML produced by the Redvers COBOL XML Interface:

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This product is listed in the IBM Global Solutions Directory and The COBOL Center Tools web site.