PL/I Migration Analyzer

Analyzes legacy PL/I programs and generates Java migration strategies. Extracts business logic, data structures, procedures, and dependencies to produce actionable migration plans.

Workflow

1. Discover PL/I Programs

Find PL/I source files in the workspace:

find . -name "*.pli" -o -name "*.PLI" -o -name "*.pl1"

2. Analyze Program Structure

For each PL/I program, extract:

• Entry points: PROCEDURE OPTIONS(MAIN)
• Declarations: DCL statements (FIXED DECIMAL, FIXED BINARY, CHARACTER, BIT, structures)
• Procedures: Nested procedures and functions
• File operations: OPEN, READ, WRITE, CLOSE statements
• Exception handling: ON conditions (ENDFILE, ERROR, etc.)
• Dependencies: CALL statements, %INCLUDE directives

Use scripts for automation:

• extract-structure.py <source_file> - Extract structural information
• analyze-dependencies.sh <directory> - Generate dependency graph
• estimate-complexity.py <source_file> - Estimate migration effort

3. Map to Java Design

Convert PL/I elements to Java:

• Structures → POJOs with appropriate types
• Procedures → Service methods
• File operations → Java I/O or database operations
• ON conditions → try-catch exception handling
• Arrays → Lists or arrays (adjust 1-based to 0-based indexing)

Critical Type Mapping:

• FIXED DECIMAL(n,m) → BigDecimal (NEVER float/double)
• FIXED BINARY(n) → int, long
• CHARACTER(n) → String
• BIT(1) → boolean

4. Generate Java Implementation

Create Java classes using:

• generate-java-classes.py <data_structure_file> - Generate POJOs from structures

Ensure:

• BigDecimal for all financial calculations
• Proper exception handling (no GO TO)
• Array bounds adjustment (1-based → 0-based)
• String operations adjustment (SUBSTR is 1-based, substring is 0-based)

5. Produce Migration Report

Generate comprehensive report with:

1. Program Overview: Purpose, entry points, complexity estimate
2. Dependencies: Called procedures, included files, external references
3. Data Structures: Tables with PL/I types and Java equivalents
4. Business Logic Summary: Key algorithms and rules
5. Java Design: Proposed classes, methods, packages
6. Migration Estimate: Effort in person-days, risk assessment
7. Action Items: Prioritized tasks with owners

Use template: assets/migration-report-template.md

Quick Reference

Common Conversions

Procedure to Method:

CALC_TOTAL: PROCEDURE(qty, price) RETURNS(FIXED DECIMAL(15,2));
    result = qty * price;
    RETURN(result);
END CALC_TOTAL;

→

public BigDecimal calcTotal(BigDecimal qty, BigDecimal price) {
    return qty.multiply(price);
}

File I/O to Streams:

DO WHILE(¬eof);
    READ FILE(infile) INTO(rec);
    CALL process_record(rec);
END;

→

try (BufferedReader reader = Files.newBufferedReader(path)) {
    reader.lines().forEach(this::processRecord);
}

Critical Rules

1. Use BigDecimal for FIXED DECIMAL - Float/double lose precision
2. Arrays are 1-based in PL/I, 0-based in Java - Adjust loops and indices
3. Refactor GO TO statements - Use structured control flow
4. ON conditions map to try-catch - Exception handling strategy required
5. SUBSTR is 1-based - Java substring is 0-based and end-exclusive

Detailed References

For comprehensive information:

• Type mapping & patterns: pli-reference.md - Complete data type conversions, code patterns, migration checklist, common pitfalls
• Pseudocode translation: pseudocode-pli-rules.md - Rules for converting PL/I to pseudocode
• Transaction handling: transaction-handling.md - Database transaction patterns
• Performance: performance-patterns.md - Optimization strategies
• Messaging: messaging-integration.md - Event-driven patterns
• Testing: testing-strategy.md - Test approach and validation

Output Format

Structure migration reports with these sections:

# [Program Name] Migration Analysis

## Executive Summary
High-level overview and recommendations

## Program Overview
Purpose, functionality, complexity metrics

## Dependencies
Procedure calls, file dependencies, external references

## Data Structures
Tables mapping PL/I structures to Java classes

## Business Logic Analysis
Key algorithms, rules, calculations

## Java Design Proposal
Package structure, class design, API interfaces

## Migration Estimate
Effort (person-days), risk level, timeline

## Action Items
Prioritized tasks with acceptance criteria