Converting BMS maps and using the Map class

A large proportion of existing CICS® applications use BMS maps for 3270 screen output. This means that the server application can use data structures corresponding to named fields in the BMS map rather than handling 3270 data streams directly. The EPI BMS conversion utility uses the information in the BMS map source to generate classes specific to individual maps, which allow fields to be accessed by their names.

The utility generates Java™ classes that applications can use to access the map data as named fields within a map object. A class is defined for each map, allowing field names and lengths to be known at compile time. The generated classes extend the class Map, which provides general functions required by all map classes.

Run the BMS map converter utility on the BMS source as follows:
java com.ibm.ctg.epi.BMSMapConvert -p package filename.BMS
The utility generates .java files containing the source for the map classes. Use the -p parameter to specify the package to put the new files into. This saves you having to edit the files to add the "package" statement.

After you have used the EPI BMS utility to generate the map class, use the base EPI classes to reach the required 3270 screens in the usual way. Then use the map classes to access fields by their names in the BMS map. The map classes are validated against the data in the current Screen object.