Flat File Parser Grouping Example

Purpose

This example shows how to group data from multiple lines into a block which will be passed to a processing program.

Data Format

The data is read from a stream file on the IFS.

This is the data from the echo example.

00012010-12-201234567890123450
00012010-12-201234567890987900

The same data could come in a different format with the data spread over multiple lines with each line containing a line identifier and the data.

1000001
1102010-12-20
2101234567890123
220450
999
1000001
1102010-12-20
2101234567890987
220900
999

or

1000001
1102010-12-20
2101234567890123
220450
2101234567890987
220900
999

Each line type is identified with an identifier (columns 1 - 3). A block of data begins and ends with a "special" line. This line can be fix or contain variable data.

In this case a complete block of data starts with a line with an identifier "100" and ends with a line with an identifier "999". So the starting line format has an image "100####" and the ending line format "999".

Line Formats

	Identifier	Data
Store ID	100	4 digits numeric
Date	110	date ISO format yyyy-MM-dd
Item	210	13 alphanumeric (EAN)
Quantity	220	4 digits numeric
End	999	no extra data

Code

Create a new parser instance

 parser = ffp_create();

Configure the line formats

 lineFormatImage = '100####' + x'00';
 ffp_addLineFormatFromImage(parser : 'store' : %addr(lineFormatImage));

 lineFormatImage = '110####-##-##' + x'00';
 ffp_addLineFormatFromImage(parser : 'date' : %addr(lineFormatImage));

 lineFormatImage = '210@@@@@@@@@@@@@' + x'00';
 ffp_addLineFormatFromImage(parser : 'item' : %addr(lineFormatImage));

 lineFormatImage = '220####' + x'00';
 ffp_addLineFormatFromImage(parser : 'quantity' : %addr(lineFormatImage));

 lineFormatImage = '999' + x'00';
 ffp_addConstantLineFormat(parser : 'end' : %addr(lineFormatImage));

Create line processor

 lineProcessor = ffp_processor_grouping_create(parser);

Configure block start and end

 // define where a block begins and ends
 ffp_processor_grouping_setStartLineFormat(lineProcessor : 
                                           ffp_getLineFormat(parser : 'id'));
 ffp_processor_grouping_setEndLineFormat(lineProcessor : 
                                         ffp_getLineFormat(parser : 'end'));

Set data processing program

 // configure which program will process the grouped data
 ffp_processor_grouping_setExecutor(lineProcessor : 'FFPEX02EX');

Set input provider

 inputProvider = rng_input_stmf_create(%addr(inputPath)); 
 ffp_setInputProvider(parser : inputProvider);

Parsing

 // do the actual parsing 
 ffp_parse(parser);
 

Cleanup

 // cleanup (all resources registered at the parser will also be cleaned up)
 ffp_finalize(parser);

Processing Program

The processing program gets the block of data from the line processor in a list data structure (though not data structure as in the RPG language, see Linked List). The program must implement the following prototype:

    D program         PR
    D   logger                        *   const
    D   data                          *   const

Each entry in the list is a data structure in the format of ffp_processor_grouping_line. The data structure contains the associated line format, the raw data and the line number.

    D ffp_processor_grouping_line...
    D                 DS                  qualified
    D   lineFormat                    *
    D   data                     65535A   varying
    D   lineNumber                  10I 0

The following code iterates through the passed data:

    D entry           DS                  likeds(ffp_processor_grouping_line)
    D                                     based(entryPtr)
    D lineFormat      DS                  likeds(ffp_lineFormat) 
    D                                     based(entry.lineFormat)
  
     ...
                     
      list_abortIteration(data);
      entryPtr = list_getNext(data);
      dow (entryPtr <> *null);
  
        // process data here
  
        entryPtr = list_getNext(data);
      enddo;    
  
     ...

Note: If you have defined fields in your configuration, you can extract the data for each field with the procedure ffp_util_getLineFormatFieldData.