An XML converter driver and a correlator file are required for IBM® Mashup Center to communicate with IMS™ Connect when you create an IMS transaction feed from an IMS application.
Because a feed is transmitted in XML format, for IBM Mashup Center to communicate with IMS Connect, the TCP/IP gateway for IMS, two files are required to convert the data between XML and bytes.
- The XML converter driver
The XML converter driver is generated based on the IMS application source file that describes the input and output language structures. Each input or output language structure needs its own converter. You must use Rational® Developer for System z® to generate all the converters for an IMS application into one driver file. The driver must be deployed to IMS Connect. IMS Connect has an XML adapter function that converts the request and response messages between XML and bytes based on your specified XML converter driver.
- The correlator file
The correlator file contains information that is required for the IBM Mashup Center to communicate with IMS Connect, such as:
- XML converter driver name
- IMS transaction code
- Number of milliseconds that IMS Connect waits for a request from IBM Mashup Center
- Number of milliseconds that IMS Connect waits for a response from IMS
- A list of parameters that is based on the input language structure of the IMS application
These two files are generated from the IMS application source file (COBOL copybook) by using Rational Developer for System z Version 7.5 or later.
Development phase of an IMS transaction feed
The XML converter driver must be deployed to IMS Connect, and the correlator file must be uploaded to IBM Mashup Center.
An application developer first generates the correlator file and the XML converters by using the Rational Developer for System z. Rational Developer for System z supports the creation of IMS Web 2.0 projects based on your COBOL copybook and generates the correlator file and XML converters that are required to convert the data between IMS and the WebSphere® Application Server that IBM Mashup Center runs on.
The developer then deploys the XML converters (generated into one driver file) to IMS Connect and creates an IMS transaction feed in IBM Mashup Center by specifying IMS connection information and uploading the generated correlator file. The generated feed is automatically registered in the mashup catalog. The following diagram describes the development phase of an IMS transaction feed.
Figure 1. Development phase of an IMS transaction feed for IBM Mashup Center
Runtime phase of an IMS transaction feed
When the WebSphere Application Server receives an HTTP request for an IMS transaction feed from a Web client, it passes the request to IBM Mashup Center, which searches the catalog and invokes the IMS transaction feed generator. The IMS transaction feed generator processes the parameters, establishes a connection with IMS Connect, and sends the request as an XML message. The XML adapter function in IMS Connect converts the XML message into byte arrays by using the XML converter driver, and sends the data as an input message for the IMS transaction. The output byte array that is returned by the IMS transaction is converted by IMS Connect into XML response data by using the converter driver. The response is then returned to the IMS transaction feed generator, which converts the response to the Atom format and sends it to the client as an HTTP response. The following diagram describes the runtime phase of an IMS transaction feed.
Figure 2. Runtime phase of an IMS transaction feed for IBM Mashup Center