Migrate CBSTM03A/CBSTM03B statement generation to Java

[devanshi-gpta]

Summary

Migrates CBSTM03A (statement driver, replacing CREASTMT.JCL) and its CBSTM03B I/O subroutine into com.carddemo.batch.statement. No files outside that package (plus the README mapping table) are touched.

The whole point of this migration is byte-level fidelity of the two outputs, so the COBOL record layouts are reproduced field by field rather than re-expressed as templates:

• StatementService.render(...) emits List<String> records padded to the DD LRECL (STMTFILE 80, HTMLFILE 100), in the exact write order of the COBOL paragraphs (5000-CREATE-STATEMENT → 5100/5200 HTML header → 6000-WRITE-TRANS per transaction → 4000-TRNXFILE-GET totals/footer). The HTML 88-level literals are transcribed verbatim, including their continuation lines.
• StatementFormatter implements the COBOL data movements the layout depends on, which are the easy things to get subtly wrong:
  • PIC 9(9).99- (ST-CURR-BAL) → 1234.56 renders as "000001234.56 ", -42.07 as "000000042.07-"; integer digits beyond nine are truncated high-order, as MOVE does.
  • PIC Z(9).99- (ST-TRANAMT / ST-TOTAL-TRAMT) → 0.75 renders as " .75 ".
  • MOVE ACCT-ID PIC 9(11) TO PIC X(20) → "00000000011" + 9 spaces.
  • STRING ... DELIMITED BY ' ' / ' ' (the name and address-line-3 builds, and the DELIMITED BY ' ' HTML variants) transfer only the part of the fixed-width sending field before the delimiter.
• StatementTransactionTable replaces the WS-TRNX-TABLE two-dimensional table: TRNXFILE is read once in TRAN-CARD-NUM + TRAN-ID order (the sort CREASTMT.JCL STEP010 performs) and grouped per card, and the per-statement scan stops at the first stored card sorting after XREF-CARD-NUM, exactly like 4000-TRNXFILE-GET. The OCCURS 51 / OCCURS 10 bounds are kept as constants; records past them are dropped with a warning instead of overwriting adjacent storage the way the COBOL would.
• StatementFileService is the CBSTM03B stand-in over the repositories (sequential XREFFILE/TRNXFILE, keyed CUSTFILE/ACCTFILE). It does not reproduce the literal CALL interface, but it keeps the status semantics: a missing keyed record raises StatementFileException("CUSTFILE", "23"), mirroring 9999-ABEND-PROGRAM.
• StatementJobConfig wraps the service in a Spring Batch job creastmtJob writing to carddemo.statement.text-file / carddemo.statement.html-file.

No new dependencies; pom.xml unchanged.

Testing

cd java && mvn -B clean verify passes (25 tests). New: layout assertions for every header line, transaction line and the Total EXP: line; HTML order/content; the numeric-edit pictures; table grouping and OCCURS limits; and a @SpringBootTest generating statements for a seeded cardxref/custdata/acctdata account with two transactions (250.00, -100.50 → total 149.50).

Link to Devin session: https://app.devin.ai/sessions/3485785cb7574e7e8391ead52ee9ee82
Requested by: @devanshi-gpta

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