_Java Native Methods and Legacy Databases_
by Yoshiki Sakai, Mark A. Schmidt, Marco Balini

Listing One
public synchronized native int  INTISAMX(String regid,String svn,
                                                  String uid, String psw);
public synchronized native int  CREIFILX(String regid,String[] isamdata,
                                                  String[] dodadata);
public synchronized native int  OPNRFILX(String regid,int filno,
                                                  String path,int filmode);
public synchronized native int  FRSREC(String regid,int keyno,
                                                  String[] recbuf);
public synchronized native int  GTEREC(String regid,int keyno,
                                             Object[] keyval,String[] recbuf);
public synchronized native int  LTEREC(String regid,int keyno,
                                             Object[] keyval,String[] recbuf);
public synchronized native int  NXTREC(String regid,int keyno,
                                                  String[] recbuf);
public synchronized native int  PRVREC(String regid,int keyno,
                                                  String[] recbuf);
public synchronized native int  LSTREC(String regid,int keyno,
                                                  String[] recbuf);
public synchronized native int  ADDREC(String regid,int datno,
                                                  String[] recbuf);
public synchronized native int  RWTREC(String regid,int datno,
                                                  String[] recbuf);
public synchronized native int  DELREC(String regid,int datno);
public synchronized native int  BATGET(String regid,int keyno,
                     Object[] keyval,String[][] recbuf,int siglen,int numrec);
public synchronized native int  BATGET_NEXT(String regid,int keyno,
                                                String[][] recbuf,int numrec);
public synchronized native int  TRANBEG(String regid);
public synchronized native int  TRANABT(String regid);
public synchronized native int  TRANEND(String regid);
public synchronized native int  CLRFIL(String regid,int datno);
public synchronized native int  STPUSR(String regid);

Listing Two
/*                                                                          *
 *  contacts.java   A simple contact manager application                    *
 *                                                                          */
 
import java.io.*;
public class Contacts 
{
    static final int    NO_ERROR=0;
    static final int    DLOK_ERR=42;
    static final int    INOT_ERR=101;
    static final int    FNOP_ERR=12;
    static final int    INOD_ERR=102;
    static final int    IGIN_ERR=103;
    static final int    IDRI_ERR=106;
    static final int    ISRC_ERR=110;
    static final int    IKRI_ERR=111;
    static final int    ISLN_ERR=115;
    static final int    IMRI_ERR=117;
    static final int    KCRAT_ERR=16;
    static final int    DCRAT_ERR=17;
    static final int    KOPN_ERR=18;
    static final int    DOPN_ERR=19;
    static final int    KDUP_ERR=2;

    static final int    ROLODAT=0;
    static final int    NAMEIDX=1;
    static final int    CUSTIDX=2;
    static final int    NUMFLD=14;
    static final int    INPBUFSIZ=300; 

/*****************************************************************************
*   MAIN    The primary method of the application.                           *
*****************************************************************************/
    public static void  main (String arg[]) 
    {
        ctree   ct = null;
        
        int     returnValue = 0;
        int     dataFileNumber = -1;

        String  instanceID = "contacts";
        
        String  userID = null;
        String  userPassword = null;
        String  serverName = "FAIRCOMS@localhost";

        String  dataField[] = new String[NUMFLD];
        String  ifilInfo[]  = new String[6];
        String  dodaInfo[]  = new String[NUMFLD+1];

        System.out.println();
        System.out.println("CONTACTS: j-tree sample application");
        System.out.println();

        for (int i = 0; i < NUMFLD; i++)    dataField[i] = "";

        /* IFIL info - pfilnam   dreclen dxtdsiz dfilmod dnumidx ixtdsiz ifilmod rfstfld  rlstfld */
        ifilInfo[0] = "rolodex     300    4096      0       2      4096      0     NULL     NULL";
    
        /* IIDX info - ikeylen ikeytyp ikeydup inulkey iempchr inumseg ridxnam aidxnam altseq */
        ifilInfo[1] = "  22       12      1       1        0      2    Nameidx   NULL   NULL";
    
        /* ISEG info - soffset slength segmod */
        ifilInfo[2] = "   19      10      2";
        ifilInfo[3] = "    4       8      2";
    
        /* IIDX info - ikeylen ikeytyp ikeydup inulkey iempchr inumseg ridxnam aidxnam altseq */
        ifilInfo[4] = "   2       0       0       1        0      1    Custidx   NULL   NULL";
    
        /* ISEG info - soffset slength segmod */
        ifilInfo[5] = "    2       2      8";
    
        /* DODA info -  Symbol Name      Type            Length */
        dodaInfo[0]  = "Del_Flag         CT_INT2         2";
        dodaInfo[1]  = "Cust_Num         CT_INT2         2";
        dodaInfo[2]  = "FirstName        CT_FSTRING      15";
        dodaInfo[3]  = "LastName         CT_FSTRING      25";
        dodaInfo[4]  = "Address1         CT_FSTRING      40";
        dodaInfo[5]  = "Address2         CT_FSTRING      40";
        dodaInfo[6]  = "City             CT_FSTRING      15";
        dodaInfo[7]  = "State            CT_FSTRING      3";
        dodaInfo[8]  = "Zip              CT_FSTRING      11";
        dodaInfo[9]  = "Phone            CT_FSTRING      15";
        dodaInfo[10] = "Fax              CT_FSTRING      15";
        dodaInfo[11] = "EMail            CT_FSTRING      30";
        dodaInfo[12] = "WebSite          CT_FSTRING      40";
        dodaInfo[13] = "Padding          CT_FSTRING      47";
        dodaInfo[14] = "END";
    
        try {
            ct = new ctree();
        } catch (ArrayIndexOutOfBoundsException e) {
            System.err.println("Fatal Error! Could not create c-tree class instance.");
            System.exit(-1);
        }
        
        if ((returnValue=ct.INTISAMX(instanceID, serverName, userID, userPassword)) != NO_ERROR)
            finalize(ct, instanceID, "Cannot initialize c-tree", returnValue);

        dataFileNumber = OpenFiles(ct, instanceID, ifilInfo, dodaInfo);
        WorkLoop(ct, instanceID, dataField, dataFileNumber);
        finalize(ct, instanceID, dataFileNumber);
    }
    public static int  OpenFiles(ctree ct, String instanceID, String[] ifilInfo, String[] dodaInfo)
    {
        int     dataFileNumber = -1;

        int        returnValue = 0;

        if ((dataFileNumber = ct.OPNRFILX(instanceID, -1, "rolodex.dat", 0)) < 0) {
            if ((dataFileNumber = ct.CREIFILX(instanceID, ifilInfo, dodaInfo)) < 0)
                finalize(ct, instanceID, "Cannot open or create inventory files", dataFileNumber);
            else {
                if ((dataFileNumber = ct.OPNRFILX(instanceID, -1, "rolodex.dat", 0)) < 0)
                    finalize(ct, instanceID, "Cannot open inventory files", dataFileNumber);
                
                System.out.println();
                System.out.print("Successfully created data files and indices");
            }
        } 
        else {
            System.out.println();
            System.out.print("Successfully opened data files and indices");
        }
        return(dataFileNumber);
    }
    public static void  WorkLoop(ctree ct, String instanceID, String[] dataField, int dataFileNumber) {

        int     keyno = dataFileNumber + CUSTIDX;
        byte    choice[] = new byte[2];

        choice[0] = '\0';

        while (choice[0] != 'Q' && choice[0] != 'q') {
            System.out.println("");
            System.out.println("");
            System.out.print("A)dd  D)elete  S)how  U)pdate  Q)uit: ");
            System.out.flush();
            try {
                System.in.read(choice);
            } catch (IOException ioe) {
                System.err.println(ioe.toString());
                ioe.printStackTrace();
            }
            switch(choice[0]) {

                case 'a':
                case 'A':
                    AddARecord(ct, instanceID, dataField, dataFileNumber);
                    break;

                case 's':
                case 'S':
                    ShowRecords(ct, instanceID, dataField, dataFileNumber);
                    break;

                case 'd':
                case 'D':
                    if (SelectARecord(ct, instanceID, dataField, dataFileNumber))
                        DeleteCurrent(ct, instanceID, dataField, dataFileNumber);
                    break;


               case 'u':
                case 'U':
                    if (SelectARecord(ct, instanceID, dataField, dataFileNumber))
                        UpdateCurrent(ct, instanceID, dataField, dataFileNumber);
                    break;

                default:
                    break;
            }
        }
    }
    public static void  AddARecord(ctree ct, String instanceID, String[] dataField, int dataFileNumber)
    {
        int returnValue = 0;

        System.out.println();
        System.out.println("ADD NEW DATA");
        System.out.println();

        for (int i = 0; i < NUMFLD; i++)    dataField[i] = "";

        GetInput(dataField);

        if ((returnValue = ct.TRANBEG(instanceID)) == 0)
            isam_error(returnValue);
        else if ((returnValue = ct.ADDREC(instanceID, dataFileNumber, dataField)) != 0) {
            System.out.print("Error adding record: " + returnValue);
            ct.TRANABT(instanceID);
        } 
        else {
            System.out.println();
            System.out.print("Successful Addition.");
            ct.TRANEND(instanceID);
        }
    }
    public static void  GetInput(String[] dataField)
    {
        dataField[1]  = GetAField("Customer Number : ", dataField[1]);
        dataField[2]  = GetAField("First Name      : ", dataField[2]);
        dataField[3]  = GetAField("Last Name       : ", dataField[3]);
        dataField[4]  = GetAField("Address (Line 1): ", dataField[4]);
        dataField[5]  = GetAField("Address (Line 2): ", dataField[5]);
        dataField[6]  = GetAField("City            : ", dataField[6]);
        dataField[7]  = GetAField("State           : ", dataField[7]);
        dataField[8]  = GetAField("Zip Code        : ", dataField[8]);
        dataField[9]  = GetAField("Phone Number    : ", dataField[9]);
        dataField[10] = GetAField("Fax Number      : ", dataField[10]);
        dataField[11] = GetAField("eMail address   : ", dataField[11]);
        dataField[12] = GetAField("Web Site URL    : ", dataField[12]);
    }
    public static String  GetAField(String Prompt, String Target)
    {
        byte    inpbuf[] = new byte[INPBUFSIZ];

        System.out.println();

        System.out.println("  Current " + Prompt + " " + Target);
        System.out.print("Enter new " + Prompt);
        System.out.flush();
        try {
            System.in.read(inpbuf);
        } catch (IOException ioe) {
            System.err.println(ioe.toString());
            ioe.printStackTrace();
        }
        String buffer = new String(inpbuf,0);
        return (buffer.trim());
    }
    public static void  ShowRecords(ctree ct, String instanceID, String[] dataField, int dataFileNumber)
    {
        int     returnValue = 0;
        int     keyno = dataFileNumber + CUSTIDX;
        byte    choice[] = new byte[2];

        choice[0] = '\0';

        if ((returnValue = ct.FRSREC(instanceID, keyno, dataField)) != NO_ERROR) {
            System.out.println("Error reading first record");
            isam_error(returnValue);
        } 
        else {
            while (choice[0] != 'Q' && choice[0] != 'q')
            {
                System.out.println();
                System.out.println();
                System.out.println("The current record is:");
                DisplayARecord(dataField);
    
                System.out.println();
                System.out.println();
                System.out.print("D)elete  E)dit  N)ext  Q)uit : ");
                System.out.flush();
                try {
                    System.in.read(choice);
                } catch (IOException ioe) {
                    System.err.println(ioe.toString());
                    ioe.printStackTrace();
                }

                switch(choice[0]) {
    
                    case 'd':
                    case 'D':
                        DeleteCurrent(ct, instanceID, dataField, dataFileNumber);
    
                    case 'n':
                    case 'N':
                        if ((returnValue = ct.NXTREC(instanceID, keyno, dataField)) != NO_ERROR) {
                            if (returnValue == INOT_ERR) {
                                System.out.print("Last record in index.");
                                choice[0] = 'q';

                           }
                            else                      
                                finalize(ct, instanceID, "Error reading next record.", returnValue);
                        }
                        break;

                    case 'e':
                    case 'E':
                        UpdateCurrent(ct, instanceID, dataField, dataFileNumber);
                        break;
    
                    default:
                        break;
                }
            }
        }
    }
    public static void  DeleteCurrent(ctree ct, String instanceID, String[] dataField, int dataFileNumber)
    {
        int returnValue = 0;
        byte    choice[] = new byte[2];
    
        System.out.println();
        System.out.print("Delete this record (Y/n)?");
        System.out.flush();
        try {
            System.in.read(choice);
        } catch (IOException ioe) {
            System.err.println(ioe.toString());
            ioe.printStackTrace();
        }

        if (choice[0] == 'n' || choice[0] == 'N')
            return;
        
        if ((returnValue = ct.TRANBEG(instanceID)) == 0)
            isam_error(returnValue);
        else if ((returnValue = ct.DELREC(instanceID, dataFileNumber)) != 0) {
            System.out.println();
            System.out.println();
            System.out.println("Delete failed (code " + returnValue + ").");
            ct.TRANABT(instanceID);
        } 
        else {
            System.out.println();
            System.out.println("The following record was deleted: ");
            DisplayARecord(dataField);
            ct.TRANEND(instanceID);
        }
    }
    public static void  UpdateCurrent(ctree ct, String instanceID, String[] dataField, int dataFileNumber)
    {
        int returnValue = 0;
        byte    choice[] = new byte[2];


        System.out.println();
        System.out.print("Edit this record (Y/n)?");
        System.out.flush();
        try {
            System.in.read(choice);
        } catch (IOException ioe) {
            System.err.println(ioe.toString());
            ioe.printStackTrace();
        }

        if (choice[0] == 'n' || choice[0] == 'N')
            return;
        
        GetInput(dataField);

        if ((returnValue = ct.TRANBEG(instanceID)) == 0) {
            isam_error(returnValue);
        } else if ((returnValue = ct.RWTREC(instanceID, dataFileNumber, dataField)) != 0) {
            System.out.println();
            System.out.println();
            System.out.println("Update failed (code " + returnValue + ").");
            ct.TRANABT(instanceID);
        } else {
            System.out.println();
            System.out.println("The following record was updated: ");
            DisplayARecord(dataField);
            ct.TRANEND(instanceID);
        }
    }
    public static boolean  SelectARecord(ctree ct, String instanceID, String[] dataField, int dataFileNumber)
    {
        int returnValue = 0;
        int keyno = dataFileNumber + CUSTIDX;
        byte    inpbuf[] = new byte[INPBUFSIZ];
        Object  target[] = new Object[1];

        System.out.println();
        System.out.print("Enter Customer Number to select: ");
        System.out.flush();
        try {
            System.in.read(inpbuf);
        } catch (IOException ioe) {
            System.err.println(ioe.toString());
            ioe.printStackTrace();
        }
        String  buffer = new String(inpbuf,0);
        target[0] = buffer;

        if ((returnValue=ct.GTEREC(instanceID, keyno, target, dataField)) != NO_ERROR) {
            isam_error(returnValue);                         
            return false;
        }
        DisplayARecord(dataField);
        return true;
    }

    public static void  DisplayARecord(String[] dataField)
    {
        System.out.println();
        System.out.println("First Name        : " + dataField[2]);
        System.out.println("Last Name         : " + dataField[3]);
        System.out.println("Address (Line One): " + dataField[4]);
        System.out.println("Address (Line Two): " + dataField[5]);
        System.out.println("City              : " + dataField[6]);
        System.out.println("State             : " + dataField[7]);
        System.out.println("Zip Code          : " + dataField[8]);
        System.out.println("Phone Number      : " + dataField[9]);
        System.out.println("Fax Number        : " + dataField[10]);
        System.out.println("email address     : " + dataField[11]);
        System.out.println("Web site URL      : " + dataField[12]);
        System.out.print("Customer Number   : " + dataField[1]);
    }
    public static void  isam_error(int isam_err)
    {
        System.out.println();

        switch (isam_err) {

            case NO_ERROR:
                break;
            case DLOK_ERR:
                System.out.print("Couldn't get lock on record");
                break;
            case INOT_ERR:
                System.out.print("Key not found.");
                break;
            case FNOP_ERR:
                System.out.print("Could not open file");
                break;
            case INOD_ERR:
                System.out.print("Could not open ISAM parameter file");
                break;
            case IGIN_ERR:
            case IDRI_ERR:
            case ISRC_ERR:
            case IKRI_ERR:
            case ISLN_ERR:
            case IMRI_ERR:
                System.out.print("Improperly formatted ISAM parameter file " + isam_err);
                break;
            case KCRAT_ERR:
            case DCRAT_ERR:
                System.out.print("Could not create file");
                break;
            case KOPN_ERR:
            case DOPN_ERR:
                System.out.print("Tried to create existing file");
                break;
            case KDUP_ERR:
                System.out.print("Key already in index");
                break;

           default:
                System.out.print("Error " + isam_err);
                break;
        }
    }
    public static void  finalize(ctree ct, String instanceID, int dataFileNumber)
    {
        int returnValue = 0;

        System.out.println();
        System.out.println("That's all.  Shutting down application.");
        System.out.println();

        if ((returnValue = ct.CLRFIL(instanceID, dataFileNumber)) != NO_ERROR)
            finalize(ct, instanceID, "Could not close ISAM system.", returnValue);

        ct.STPUSR(instanceID);
        System.exit(0);
    }
    public static void  finalize(ctree ct, String instanceID, String termsg, int isam_err)
    {
        System.out.println();
        System.out.println(termsg);

        isam_error(isam_err);

        ct.STPUSR(instanceID);
        System.exit(1);
    }
}