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

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

  → Java

   
  public class Varlnk extends StructureModel {
     private int sizes[];
     public PictureType<Integer> Varlnk1 = new PictureType<>(PictureType.Type.Integer, new DecimalFormat("999"));
     public PictureType<String> Varlnk2 = new PictureType<>(PictureType.Type.String, new AlphanumericFormat("X(10)"));
     public PictureType<Integer> Varlnk3 = new PictureType<>(PictureType.Type.Integer, new DecimalFormat("9(7)"));
     public Varlnk() {
        sizes = new int[] { Varlnk1.getSize(),Varlnk2.getSize(),Varlnk3.getSize() };
     }
     @Override
     public String toString() {
        return "" + Varlnk1 + Varlnk2 + Varlnk3;
     }
     @Override
     public void setData(char[] data) {
        setData(getStringValues(data, sizes));
     }
     @Override
     public void setData(String[] data) {
        Varlnk1.setDataFromFile(data[0].getBytes());
        Varlnk2.setValue(data[1]);
        Varlnk3.setDataFromFile(data[2].getBytes());
     }
     @Override
     public int getSize() {
        int sum = 0;
        for(int i = 0; i < sizes.length; i ++) {
           sum += sizes[i];
        }
        return sum;
     }
     @Override
     public void initialize() {
        Varlnk1.initialize();
        Varlnk2.initialize();
        Varlnk3.initialize();
     }
     @Override
     public byte[] toFile() {
        byte[] structure = new byte[] { };
        structure = ArrayUtils.addAll(structure, Varlnk1.toFile());
        structure = ArrayUtils.addAll(structure, Varlnk2.toFile());
        structure = ArrayUtils.addAll(structure, Varlnk3.toFile());
        return structure;
     }
     @Override
     public void setDataFromFile(byte[] bytes) {
        bytes = getFullArray(bytes);
        Varlnk1.setDataFromFile(Arrays.copyOf(bytes, Varlnk1.getSize()));
        bytes = Arrays.copyOfRange(bytes, Varlnk1.getSize(), bytes.length);
        Varlnk2.setDataFromFile(Arrays.copyOf(bytes, Varlnk2.getSize()));
        bytes = Arrays.copyOfRange(bytes, Varlnk2.getSize(), bytes.length);
        Varlnk3.setDataFromFile(Arrays.copyOf(bytes, Varlnk3.getSize()));
        bytes = Arrays.copyOfRange(bytes, Varlnk3.getSize(), bytes.length);
     }
     @Override
     public void setDefaultValue(PictureType.DefaultValue value) {
        Varlnk1.setDefaultValueFromStructure(value);
        Varlnk2.setDefaultValueFromStructure(value);
        Varlnk3.setDefaultValueFromStructure(value);
     }
  }
   
      public Varlnk varlnk = new Varlnk();
   

• Common REDEFINES conversion:

  COBOL

   
  01 var1 PIC XXX  VALUE '111'.
  01 var2 REDEFINES var1.
    05  vvv1  PIC 9.
    05  vvv2  PIC 99.
   

  → Java

   
  private StrField Var1 = new StrField("XXX", "111");
  public Var2 var2 = new Var2(Var1);
   
   
  public class Var2 extends StructureModel {
     private int sizes[];
     public PictureType<Integer> Vvv1 = new PictureType<>(PictureType.Type.Integer, new DecimalFormat("9"));
     public PictureType<Integer> Vvv2 = new PictureType<>(PictureType.Type.Integer, new DecimalFormat("99"));
     public Var2(StructureModel ... objs) {
        sizes = new int[] { Vvv1.getSize(),Vvv2.getSize() };
        initRedefineObjs(objs);
     }
     @Override
     public String toString() {
        return "" + Vvv1 + Vvv2;
     }
     @Override
     public void setData(char[] data) {
        setData(getStringValues(data, sizes));
     }
     @Override
     public void setData(String[] data) {
        Vvv1.setDataFromFile(data[0].getBytes());
        Vvv2.setDataFromFile(data[1].getBytes());
        redefine();
     }
     public void setVvv1(Integer Vvv1) {
        this.Vvv1.setValue(Vvv1);
        redefine();
     }
     public void setVvv2(Integer Vvv2) {
        this.Vvv2.setValue(Vvv2);
        redefine();
     }
     @Override
     public int getSize() {
        int sum = 0;
        for(int i = 0; i < sizes.length; i ++) {
           sum += sizes[i];
        }
        return sum;
     }
     @Override
     public void initialize() {
        Vvv1.initialize();
        Vvv2.initialize();
     }
     @Override
     public byte[] toFile() {
        byte[] structure = new byte[] { };
        structure = ArrayUtils.addAll(structure, Vvv1.toFile());
        structure = ArrayUtils.addAll(structure, Vvv2.toFile());
        return structure;
     }
     @Override
     public void setDataFromFile(byte[] bytes) {
        bytes = getFullArray(bytes);
        Vvv1.setDataFromFile(Arrays.copyOf(bytes, Vvv1.getSize()));
        bytes = Arrays.copyOfRange(bytes, Vvv1.getSize(), bytes.length);
        Vvv2.setDataFromFile(Arrays.copyOf(bytes, Vvv2.getSize()));
        bytes = Arrays.copyOfRange(bytes, Vvv2.getSize(), bytes.length);
     }
     @Override
     public void setDefaultValue(PictureType.DefaultValue value) {
        Vvv1.setDefaultValueFromStructure(value);
        Vvv2.setDefaultValueFromStructure(value);
        redefine();
     }
  }
   

• Common array conversion:

  COBOL

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

  → Java

   
    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

   
  TopLevel.
      DISPLAY "In TopLevel. Starting to run program"
      PERFORM OneLevelDown
      DISPLAY "Back in TopLevel.".
      STOP RUN.
   
  OneLevelDown.
      DISPLAY ">>>> Now in OneLevelDown"
      PERFORM TwoLevelsDown
      DISPLAY ">>>> Back in OneLevelDown".
   
  TwoLevelsDown.
      DISPLAY ">>>>>>>> Now in TwoLevelsDown."
      PERFORM ThreeLevelsDown.
      DISPLAY ">>>>>>>> Back in TwoLevelsDown.".
   
  ThreeLevelsDown.
      DISPLAY ">>>>>>>>>>>> Now in ThreeLevelsDown".
   

  → Java

   
  private static CobSmplCbl instance;
  public boolean isCalled = false;
   
  public void CobSmplCblProcedureDivision() {
      toplevel(true);
  }
  private void toplevel(boolean isPerform) {
      System.out.println("In TopLevel. Starting to run program");
      oneleveldown(false);
      System.out.println("Back in TopLevel.");
      throw new StopRun();
  }
  private void oneleveldown(boolean isPerform) {
      System.out.println(">>>> Now in OneLevelDown ");
      twolevelsdown (false);
      System.out.println(">>>> Back in OneLevelDown ");
  }
  private void twolevelsdown(boolean isPerform) {
      System.out.println(">>>>>>>> Now in TwoLevelsDown.");
      threelevelsdown(false);
      System.out.println(">>>>>>>> Back in TwoLevelsDown.");
  }
  private void threelevelsdown(boolean isPerform) {
      System.out.println(">>>>>>>>>>>> Now in ThreeLevelsDown");
  }
  public static CobSmplCbl getInstance() {
      return instance == null ? instance = new CobSmplCbl() : instance;
  }
   
  public static void cancel() {
      instance = new CobSmplCbl();
  }              
   

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

   
    if  var3 = var4
        move "D" to var3
    else
        move " " to var3.
   

  → Java

   
    if (Var3.compareTo(Var4) == 0) {
        Var1.setData("D");
    }
    else {
        Var3.setValue(" ");
    }
   

• PERFORM UNTIL statement conversion:

  COBOL

   
    PERFORM UNTIL IterCount = 5
       ADD 1 TO IterCount
    END-PERFORM
   

  → Java

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