Convert COBOL to Java

Conversion Samples of COBOL to Java

Ispirer Toolkit analyzes all object dependencies during the conversion process and provides not only line-by-line conversion, but resolves type conversions as well. The software understands and transforms the necessary inheritance dependencies. It parses the entire source code, builds an internal tree with all the information about the objects, and uses it in the migration process.

To convert structures, we have implemented additional type conversion classes to store variable sizes to convert redefines and arrays so that they work similar to COBOL logic.

The code samples below provide you with more details.

• Common variables declaration structure conversion:

  COBOL

  1. 01 varlnk.
  2.   05 varlnk-1 PIC 999.
  3.   05 varlnk-2 PIC X(10).
  4.   05 varlnk-3 PIC 9(7).

  → Java

  1. public class Varlnk extends StructureModel {
  2.    private int sizes[];
  3.    public PictureType<Integer> Varlnk1 = new PictureType<>(PictureType.Type.Integer, new DecimalFormat("999"));
  4.    public PictureType<String> Varlnk2 = new PictureType<>(PictureType.Type.String, new AlphanumericFormat("X(10)"));
  5.    public PictureType<Integer> Varlnk3 = new PictureType<>(PictureType.Type.Integer, new DecimalFormat("9(7)"));
  6.    public Varlnk() {
  7.       sizes = new int[] { Varlnk1.getSize(),Varlnk2.getSize(),Varlnk3.getSize() };
  8.    }
  9.    @Override
  10.    public String toString() {
  11.       return "" + Varlnk1 + Varlnk2 + Varlnk3;
  12.    }
  13.    @Override
  14.    public void setData(char[] data) {
  15.       setData(getStringValues(data, sizes));
  16.    }
  17.    @Override
  18.    public void setData(String[] data) {
  19.       Varlnk1.setDataFromFile(data[0].getBytes());
  20.       Varlnk2.setValue(data[1]);
  21.       Varlnk3.setDataFromFile(data[2].getBytes());
  22.    }
  23.    @Override
  24.    public int getSize() {
  25.       int sum = 0;
  26.       for(int i = 0; i < sizes.length; i ++) {
  27.          sum += sizes[i];
  28.       }
  29.       return sum;
  30.    }
  31.    @Override
  32.    public void initialize() {
  33.       Varlnk1.initialize();
  34.       Varlnk2.initialize();
  35.       Varlnk3.initialize();
  36.    }
  37.    @Override
  38.    public byte[] toFile() {
  39.       byte[] structure = new byte[] { };
  40.       structure = ArrayUtils.addAll(structure, Varlnk1.toFile());
  41.       structure = ArrayUtils.addAll(structure, Varlnk2.toFile());
  42.       structure = ArrayUtils.addAll(structure, Varlnk3.toFile());
  43.       return structure;
  44.    }
  45.    @Override
  46.    public void setDataFromFile(byte[] bytes) {
  47.       bytes = getFullArray(bytes);
  48.       Varlnk1.setDataFromFile(Arrays.copyOf(bytes, Varlnk1.getSize()));
  49.       bytes = Arrays.copyOfRange(bytes, Varlnk1.getSize(), bytes.length);
  50.       Varlnk2.setDataFromFile(Arrays.copyOf(bytes, Varlnk2.getSize()));
  51.       bytes = Arrays.copyOfRange(bytes, Varlnk2.getSize(), bytes.length);
  52.       Varlnk3.setDataFromFile(Arrays.copyOf(bytes, Varlnk3.getSize()));
  53.       bytes = Arrays.copyOfRange(bytes, Varlnk3.getSize(), bytes.length);
  54.    }
  55.    @Override
  56.    public void setDefaultValue(PictureType.DefaultValue value) {
  57.       Varlnk1.setDefaultValueFromStructure(value);
  58.       Varlnk2.setDefaultValueFromStructure(value);
  59.       Varlnk3.setDefaultValueFromStructure(value);
  60.    }
  61. }
  62.  
  63.     public Varlnk varlnk = new Varlnk();

• Common REDEFINES conversion:

  COBOL

  1. 01 var1 PIC XXX  VALUE '111'.
  2. 01 var2 REDEFINES var1.
  3.   05  vvv1  PIC 9.
  4.   05  vvv2  PIC 99.

  → Java

  1. private StrField Var1 = new StrField("XXX", "111");
  2. public Var2 var2 = new Var2(Var1);
  3.  
  4.  
  5. public class Var2 extends StructureModel {
  6.    private int sizes[];
  7.    public PictureType<Integer> Vvv1 = new PictureType<>(PictureType.Type.Integer, new DecimalFormat("9"));
  8.    public PictureType<Integer> Vvv2 = new PictureType<>(PictureType.Type.Integer, new DecimalFormat("99"));
  9.    public Var2(StructureModel ... objs) {
  10.       sizes = new int[] { Vvv1.getSize(),Vvv2.getSize() };
  11.       initRedefineObjs(objs);
  12.    }
  13.    @Override
  14.    public String toString() {
  15.       return "" + Vvv1 + Vvv2;
  16.    }
  17.    @Override
  18.    public void setData(char[] data) {
  19.       setData(getStringValues(data, sizes));
  20.    }
  21.    @Override
  22.    public void setData(String[] data) {
  23.       Vvv1.setDataFromFile(data[0].getBytes());
  24.       Vvv2.setDataFromFile(data[1].getBytes());
  25.       redefine();
  26.    }
  27.    public void setVvv1(Integer Vvv1) {
  28.       this.Vvv1.setValue(Vvv1);
  29.       redefine();
  30.    }
  31.    public void setVvv2(Integer Vvv2) {
  32.       this.Vvv2.setValue(Vvv2);
  33.       redefine();
  34.    }
  35.    @Override
  36.    public int getSize() {
  37.       int sum = 0;
  38.       for(int i = 0; i < sizes.length; i ++) {
  39.          sum += sizes[i];
  40.       }
  41.       return sum;
  42.    }
  43.    @Override
  44.    public void initialize() {
  45.       Vvv1.initialize();
  46.       Vvv2.initialize();
  47.    }
  48.    @Override
  49.    public byte[] toFile() {
  50.       byte[] structure = new byte[] { };
  51.       structure = ArrayUtils.addAll(structure, Vvv1.toFile());
  52.       structure = ArrayUtils.addAll(structure, Vvv2.toFile());
  53.       return structure;
  54.    }
  55.    @Override
  56.    public void setDataFromFile(byte[] bytes) {
  57.       bytes = getFullArray(bytes);
  58.       Vvv1.setDataFromFile(Arrays.copyOf(bytes, Vvv1.getSize()));
  59.       bytes = Arrays.copyOfRange(bytes, Vvv1.getSize(), bytes.length);
  60.       Vvv2.setDataFromFile(Arrays.copyOf(bytes, Vvv2.getSize()));
  61.       bytes = Arrays.copyOfRange(bytes, Vvv2.getSize(), bytes.length);
  62.    }
  63.    @Override
  64.    public void setDefaultValue(PictureType.DefaultValue value) {
  65.       Vvv1.setDefaultValueFromStructure(value);
  66.       Vvv2.setDefaultValueFromStructure(value);
  67.       redefine();
  68.    }
  69. }

• Common array conversion:

  COBOL

  1. 01 var5.
  2.    05 var5-occurs OCCURS 2 TIMES.
  3.       10 var5-occurs-txt PIC X(6) VALUE ' TEXT1'.

  → Java

  1. public List<PictureType<String>> Var5 = Stream.generate(()->new PictureType<String>(new AlphanumericFormat("X(6)"), " TEXT1")).limit(2).collect(Collectors.toList());

• COBOL call chain with PERFORMs conversion:

  COBOL

  1. TopLevel.
  2.     DISPLAY "In TopLevel. Starting to run program"
  3.     PERFORM OneLevelDown
  4.     DISPLAY "Back in TopLevel.".
  5.     STOP RUN.
  6.  
  7. OneLevelDown.
  8.     DISPLAY ">>>> Now in OneLevelDown"
  9.     PERFORM TwoLevelsDown
  10.     DISPLAY ">>>> Back in OneLevelDown".
  11.  
  12. TwoLevelsDown.
  13.     DISPLAY ">>>>>>>> Now in TwoLevelsDown."
  14.     PERFORM ThreeLevelsDown.
  15.     DISPLAY ">>>>>>>> Back in TwoLevelsDown.".
  16.  
  17. ThreeLevelsDown.
  18.     DISPLAY ">>>>>>>>>>>> Now in ThreeLevelsDown".

  → Java

  1. private static CobSmplCbl instance;
  2. public boolean isCalled = false;
  3.  
  4. public void CobSmplCblProcedureDivision() {
  5.     toplevel(true);
  6. }
  7. private void toplevel(boolean isPerform) {
  8.     System.out.println("In TopLevel. Starting to run program");
  9.     oneleveldown(false);
  10.     System.out.println("Back in TopLevel.");
  11.     throw new StopRun();
  12. }
  13. private void oneleveldown(boolean isPerform) {
  14.     System.out.println(">>>> Now in OneLevelDown ");
  15.     twolevelsdown (false);
  16.     System.out.println(">>>> Back in OneLevelDown ");
  17. }
  18. private void twolevelsdown(boolean isPerform) {
  19.     System.out.println(">>>>>>>> Now in TwoLevelsDown.");
  20.     threelevelsdown(false);
  21.     System.out.println(">>>>>>>> Back in TwoLevelsDown.");
  22. }
  23. private void threelevelsdown(boolean isPerform) {
  24.     System.out.println(">>>>>>>>>>>> Now in ThreeLevelsDown");
  25. }
  26. public static CobSmplCbl getInstance() {
  27.     return instance == null ? instance = new CobSmplCbl() : instance;
  28. }
  29.  
  30. public static void cancel() {
  31.     instance = new CobSmplCbl();
  32. }

Copy statement conversion

During the conversion stage, the code from the copy files is included in the program and replaced with the appropriate copy statements, thereafter the program converts the entire code.

• If statement conversion:

  COBOL

  1. if  var3 = var4
  2.       move "D" to var3
  3.   else
  4.       move " " to var3.

  → Java

  1. if (Var3.compareTo(Var4) == 0) {
  2.       Var3.setData("D");
  3.   }
  4.   else {
  5.       Var3.setValue(" ");
  6.   }

• PERFORM UNTIL statement conversion:

  COBOL

  1. PERFORM UNTIL IterCount = 5
  2.      ADD 1 TO IterCount
  3.   END-PERFORM

  → Java

  1. while (Itercount != 5) {
  2.       Itercount.setValue(Itercount + 1);
  3.   }