feat: Migrate COBOL codebase to Java Spring Boot application

.gitignore

@@ -1,2 +1,3 @@
 **/bin
+**/target/
 

java-migration/pom.xml

@@ -0,0 +1,103 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0
+         https://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <parent>
+        <groupId>org.springframework.boot</groupId>
+        <artifactId>spring-boot-starter-parent</artifactId>
+        <version>3.2.5</version>
+        <relativePath/>
+    </parent>
+
+    <groupId>com.example</groupId>
+    <artifactId>cobol-migration</artifactId>
+    <version>0.0.1-SNAPSHOT</version>
+    <name>cobol-migration</name>
+    <description>Java Spring Boot migration of COBOL Examples</description>
+
+    <properties>
+        <java.version>17</java.version>
+    </properties>
+
+    <dependencies>
+        <!-- Spring Boot Starters -->
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-web</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-data-jpa</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-validation</artifactId>
+        </dependency>
+
+        <!-- PostgreSQL JDBC Driver -->
+        <dependency>
+            <groupId>org.postgresql</groupId>
+            <artifactId>postgresql</artifactId>
+            <scope>runtime</scope>
+        </dependency>
+
+        <!-- Flyway for database migrations -->
+        <dependency>
+            <groupId>org.flywaydb</groupId>
+            <artifactId>flyway-core</artifactId>
+        </dependency>
+
+
+        <!-- Jackson XML for XML serialization (replacing XML GENERATE) -->
+        <dependency>
+            <groupId>com.fasterxml.jackson.dataformat</groupId>
+            <artifactId>jackson-dataformat-xml</artifactId>
+        </dependency>
+
+        <!-- JAXB for XML generation with attributes -->
+        <dependency>
+            <groupId>jakarta.xml.bind</groupId>
+            <artifactId>jakarta.xml.bind-api</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.glassfish.jaxb</groupId>
+            <artifactId>jaxb-runtime</artifactId>
+        </dependency>
+
+        <!-- Apache POI for report generation (replacing Report Writer) -->
+        <dependency>
+            <groupId>org.apache.poi</groupId>
+            <artifactId>poi</artifactId>
+            <version>5.2.5</version>
+        </dependency>
+        <dependency>
+            <groupId>org.apache.poi</groupId>
+            <artifactId>poi-ooxml</artifactId>
+            <version>5.2.5</version>
+        </dependency>
+
+        <!-- Testing -->
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-test</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>com.h2database</groupId>
+            <artifactId>h2</artifactId>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.springframework.boot</groupId>
+                <artifactId>spring-boot-maven-plugin</artifactId>
+            </plugin>
+        </plugins>
+    </build>
+</project>

java-migration/src/main/java/com/example/cobolmigration/CobolMigrationApplication.java

@@ -0,0 +1,12 @@
+package com.example.cobolmigration;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication
+public class CobolMigrationApplication {
+
+    public static void main(String[] args) {
+        SpringApplication.run(CobolMigrationApplication.class, args);
+    }
+}

java-migration/src/main/java/com/example/cobolmigration/config/AppConfig.java

@@ -0,0 +1,62 @@
+package com.example.cobolmigration.config;
+
+import org.springframework.context.annotation.Configuration;
+import org.springframework.dao.DataAccessException;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.ExceptionHandler;
+import org.springframework.web.bind.annotation.RestControllerAdvice;
+
+/**
+ * Application configuration and global exception handling.
+ *
+ * The {@link GlobalExceptionHandler} replaces the COBOL check-sql-state
+ * paragraph (sql/sql_example.cbl lines 443-472) which checks SQLCODE /
+ * SQLSTATE and terminates on error.  Instead of terminating, we return
+ * appropriate HTTP error responses.
+ */
+@Configuration
+public class AppConfig {
+
+    @RestControllerAdvice
+    public static class GlobalExceptionHandler {
+
+        /**
+         * Handles database access errors, replacing the COBOL pattern of
+         * checking SQLCODE after every EXEC SQL statement.
+         */
+        @ExceptionHandler(DataAccessException.class)
+        public ResponseEntity<ErrorResponse> handleDataAccessException(
+                DataAccessException ex) {
+            ErrorResponse error = new ErrorResponse(
+                    "Database error",
+                    ex.getMostSpecificCause().getMessage());
+            return ResponseEntity
+                    .status(HttpStatus.INTERNAL_SERVER_ERROR)
+                    .body(error);
+        }
+
+        @ExceptionHandler(IllegalArgumentException.class)
+        public ResponseEntity<ErrorResponse> handleIllegalArgument(
+                IllegalArgumentException ex) {
+            ErrorResponse error = new ErrorResponse(
+                    "Invalid request", ex.getMessage());
+            return ResponseEntity
+                    .status(HttpStatus.BAD_REQUEST)
+                    .body(error);
+        }
+
+        @ExceptionHandler(Exception.class)
+        public ResponseEntity<ErrorResponse> handleGenericException(
+                Exception ex) {
+            ErrorResponse error = new ErrorResponse(
+                    "Internal server error", ex.getMessage());
+            return ResponseEntity
+                    .status(HttpStatus.INTERNAL_SERVER_ERROR)
+                    .body(error);
+        }
+    }
+
+    public record ErrorResponse(String error, String detail) {
+    }
+}

java-migration/src/main/java/com/example/cobolmigration/controller/AccountController.java

@@ -0,0 +1,59 @@
+package com.example.cobolmigration.controller;
+
+import com.example.cobolmigration.entity.Account;
+import com.example.cobolmigration.service.AccountService;
+import java.util.List;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RequestParam;
+import org.springframework.web.bind.annotation.RestController;
+
+/**
+ * REST controller replacing the terminal-based menu system from
+ * sql/sql_example.cbl (lines 155-186).
+ *
+ * COBOL menu option mapping:
+ *   1) Display all accounts     -> GET /api/accounts
+ *   2) Display disabled accounts -> GET /api/accounts/disabled
+ *   3) Query accounts           -> GET /api/accounts/search?q={value}
+ *   4) Exit                     -> (not applicable for REST)
+ */
+@RestController
+@RequestMapping("/api/accounts")
+public class AccountController {
+
+    private final AccountService accountService;
+
+    public AccountController(AccountService accountService) {
+        this.accountService = accountService;
+    }
+
+    /**
+     * Replaces menu option "1) Display all accounts".
+     */
+    @GetMapping
+    public ResponseEntity<List<Account>> getAllAccounts() {
+        return ResponseEntity.ok(accountService.getAllAccounts());
+    }
+
+    /**
+     * Replaces menu option "2) Display disabled accounts".
+     */
+    @GetMapping("/disabled")
+    public ResponseEntity<List<Account>> getDisabledAccounts() {
+        return ResponseEntity.ok(accountService.getDisabledAccounts());
+    }
+
+    /**
+     * Replaces menu option "3) Query accounts".
+     *
+     * The COBOL implementation wraps the trimmed search value with '%'
+     * wildcards and queries across FIRST_NAME, LAST_NAME, PHONE, and ADDRESS.
+     */
+    @GetMapping("/search")
+    public ResponseEntity<List<Account>> searchAccounts(
+            @RequestParam("q") String searchValue) {
+        return ResponseEntity.ok(accountService.searchAccounts(searchValue));
+    }
+}

java-migration/src/main/java/com/example/cobolmigration/controller/DemoController.java

@@ -0,0 +1,120 @@
+package com.example.cobolmigration.controller;
+
+import com.example.cobolmigration.dto.JsonRecord;
+import com.example.cobolmigration.dto.SearchItem;
+import com.example.cobolmigration.service.ReportService;
+import com.example.cobolmigration.service.ReportService.StudentRecord;
+import com.example.cobolmigration.service.SerializationService;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import org.springframework.http.MediaType;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RequestParam;
+import org.springframework.web.bind.annotation.RestController;
+
+/**
+ * REST controller demonstrating the non-SQL COBOL module equivalents:
+ * JSON generation, XML generation, report writing, search table, and
+ * CLI argument handling.
+ */
+@RestController
+@RequestMapping("/api/demo")
+public class DemoController {
+
+    private final SerializationService serializationService;
+    private final ReportService reportService;
+
+    public DemoController(SerializationService serializationService,
+                          ReportService reportService) {
+        this.serializationService = serializationService;
+        this.reportService = reportService;
+    }
+
+    /**
+     * Demonstrates JSON generation replacing json_generate/json_generate.cbl.
+     */
+    @GetMapping("/json")
+    public ResponseEntity<JsonRecord> jsonDemo() {
+        JsonRecord sample = serializationService.createSampleJsonRecord();
+        return ResponseEntity.ok(sample);
+    }
+
+    /**
+     * Demonstrates XML generation replacing xml_generate/xml_generate.cbl.
+     * Returns the raw XML string with the XML declaration.
+     */
+    @GetMapping(value = "/xml", produces = MediaType.APPLICATION_XML_VALUE)
+    public ResponseEntity<String> xmlDemo() {
+        String xml = serializationService.generateXml(
+                serializationService.createSampleXmlRecord());
+        return ResponseEntity.ok(xml);
+    }
+
+    /**
+     * Generates a text report replacing report_writer/report_test.cbl.
+     * Accepts an optional format parameter (text or csv).
+     */
+    @GetMapping(value = "/report", produces = MediaType.TEXT_PLAIN_VALUE)
+    public ResponseEntity<String> reportDemo(
+            @RequestParam(value = "format", defaultValue = "text") String format) {
+        List<StudentRecord> sampleData = List.of(
+                new StudentRecord(334500, "Alice Johnson", "CSC", 5),
+                new StudentRecord(334501, "Bob Smith", "PHY", 12),
+                new StudentRecord(334502, "Carol White", "MAT", 8),
+                new StudentRecord(334503, "David Brown", "ENG", 3));
+
+        String report;
+        if ("csv".equalsIgnoreCase(format)) {
+            report = reportService.generateCsvReport(sampleData);
+        } else {
+            report = reportService.generateTextReport(sampleData);
+        }
+        return ResponseEntity.ok(report);
+    }
+
+    /**
+     * Demonstrates binary search on a sorted table, replacing
+     * search/search.cbl SEARCH ALL behaviour.
+     *
+     * Populates a list with the same test data as the COBOL program's
+     * setup-test-data paragraph and performs a binary search by id1.
+     */
+    @GetMapping("/search")
+    public ResponseEntity<Object> searchDemo(
+            @RequestParam(value = "id1", defaultValue = "0") int id1) {
+        List<SearchItem> table = new ArrayList<>();
+        table.add(new SearchItem(1000, 2000, 9000, "First Item", "2021/08/30"));
+        table.add(new SearchItem(2000, 3000, 8000, "Second Item", "2021/09/15"));
+        table.add(new SearchItem(3000, 4000, 7000, "Third Item", "2021/10/01"));
+        Collections.sort(table);
+
+        SearchItem key = new SearchItem(id1, 0, 0, null, null);
+        int index = Collections.binarySearch(table, key,
+                (a, b) -> Integer.compare(a.getId1(), b.getId1()));
+
+        if (index >= 0) {
+            return ResponseEntity.ok(table.get(index));
+        }
+        return ResponseEntity.ok("Item not found.");
+    }
+
+    /**
+     * Demonstrates CLI argument handling replacing read_command_args/ module.
+     * In a REST context the "arguments" are query parameters.
+     * The COBOL program checks for '--test' in the command line args.
+     */
+    @GetMapping("/args")
+    public ResponseEntity<String> argsDemo(
+            @RequestParam(value = "args", defaultValue = "") String args) {
+        StringBuilder response = new StringBuilder();
+        response.append("Full command line args: ").append(args).append("\n");
+
+        if (args.toLowerCase().contains("--test")) {
+            response.append("You entered the '--test' cmd arg!\n");
+        }
+        return ResponseEntity.ok(response.toString());
+    }
+}