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IBM Toolbox for Java Example: Using Record-level Access Classes


Example: Using record-level access classes to read records from a file
Note: Read the Code example disclaimer
for important legal information.


///////////////////////////////////////////////////////////////////////////////
//
// Record-Level Access example.  This program uses the record-level
// access classes to read records from a file on the system.
//
// Command syntax:
//    java RLReadFile system
//
// This program reads the records from CA/400's sample database file
// (QCUSTCDT in library QIWS).  If you change this example to update
// records you should make a copy of QCUSTCDT and update the copy.
//
// This source is an example of IBM Toolbox for Java "Record-level access".
//
///////////////////////////////////////////////////////////////////////////////


import java.io.*;
import java.util.*;
import java.math.*;
import com.ibm.as400.access.*;

public class RLReadFile extends Object
{
   public static void main(String[] parameters)
   {

      String system = "";

      // Continue only if a system name was specified.

      if (parameters.length >= 1)
      {

         try
         {

            // Assume the first parameter is the system name.

            system = parameters[0];

            // Create an AS400 object for the system that has the file.

            AS400 as400 = new AS400(system);


            // Create a record description for the file.  The file is QCUSTCDT
            // in library QIWS.
  
            ZonedDecimalFieldDescription customerNumber =
                          new ZonedDecimalFieldDescription(new AS400ZonedDecimal(6,0),
                                                           "CUSNUM");
            CharacterFieldDescription lastName =
                          new CharacterFieldDescription(new AS400Text(8, as400), "LSTNAM");

            CharacterFieldDescription initials =
                          new CharacterFieldDescription(new AS400Text(3, as400), "INIT");

            CharacterFieldDescription street =
                          new CharacterFieldDescription(new AS400Text(13, as400), "STREET");

            CharacterFieldDescription city =
                          new CharacterFieldDescription(new AS400Text(6, as400), "CITY");

            CharacterFieldDescription state =
                          new CharacterFieldDescription(new AS400Text(2, as400), "STATE");

            ZonedDecimalFieldDescription zipCode =
                          new ZonedDecimalFieldDescription(new AS400ZonedDecimal(5,0),
                                                           "ZIPCOD");
            ZonedDecimalFieldDescription creditLimit =
                          new ZonedDecimalFieldDescription(new AS400ZonedDecimal(4,0),
                                                           "CDTLMT");
            ZonedDecimalFieldDescription chargeCode =
                          new ZonedDecimalFieldDescription(new AS400ZonedDecimal(1,0),
                                                           "CHGCOD");
            ZonedDecimalFieldDescription balanceDue =
                          new ZonedDecimalFieldDescription(new AS400ZonedDecimal(6,2),
                                                           "BALDUE");
            ZonedDecimalFieldDescription creditDue =
                          new ZonedDecimalFieldDescription(new AS400ZonedDecimal(6,2),
                                                           "CDTDUE");
       
 
            // The record format name should be specified for a DDM file.
            // In the case of the QCUSTCDT file, its record format is called CUSREC.

            RecordFormat qcustcdt = new RecordFormat("CUSREC");

            qcustcdt.addFieldDescription(customerNumber);
            qcustcdt.addFieldDescription(lastName);
            qcustcdt.addFieldDescription(initials);
            qcustcdt.addFieldDescription(street);
            qcustcdt.addFieldDescription(city);
            qcustcdt.addFieldDescription(state);
            qcustcdt.addFieldDescription(zipCode);
            qcustcdt.addFieldDescription(creditLimit);
            qcustcdt.addFieldDescription(chargeCode);
            qcustcdt.addFieldDescription(balanceDue);
            qcustcdt.addFieldDescription(creditDue);


            // Create the sequential file object that represents the
            // file on the system.  We use a QSYSObjectPathName object
            // to get the name of the file into the correct format.

            QSYSObjectPathName fileName = new QSYSObjectPathName("QIWS",
                                                                 "QCUSTCDT",
                                                                 "FILE");

            SequentialFile file = new SequentialFile(as400, fileName.getPath());


            // Let the file object know the format of the records.

            file.setRecordFormat(qcustcdt);


            // Open the file for read-only access.  Specify a blocking
            // factor of 10 (the file object will get 10 records when
            // it accesses the system for data).  Do not use commitment
            // control.

            file.open(SequentialFile.READ_ONLY,
                      10,
                      SequentialFile.COMMIT_LOCK_LEVEL_NONE);


            // Read the first record of the file.

            Record data = file.readNext();


            // Loop while there are records in the file (while we have not
            // reached end-of-file).

            while (data != null)
            {

               // Display the record only if balance due is greater than
               // zero.  In that case display the customer name and
               // the balance due.  The following code pulls fields out
               // of the record by field name.  As the field is retrieved
               // from the record it is converted from i5/OS format to
               // Java format.

               if (((BigDecimal)data.getField("BALDUE")).floatValue() > 0.0)
               {
                  System.out.print((String) data.getField("INIT") + "  ");
                  System.out.print((String) data.getField("LSTNAM") + "  ");
                  System.out.println((BigDecimal) data.getField("BALDUE"));
               }

               // Read the next record in the file.

               data = file.readNext();
            }


            // When there are no more records to read, disconnect from the system.

            as400.disconnectAllServices();
         }

         catch (Exception e)
         {

            // If any of the above operations failed, print an error message
            // and output the exception.

            System.out.println("Could not read the file");
            System.out.println(e);
         }
      }


      // Display help text when parameters are incorrect.

      else
      {
         System.out.println("");
         System.out.println("");
         System.out.println("");
         System.out.println("Parameters are not correct.  Command syntax is:");
         System.out.println("");
         System.out.println("   RLReadFile as400");
         System.out.println("");
         System.out.println("Where");
         System.out.println("");
         System.out.println("   as400 = system that contains the file");
         System.out.println("");
         System.out.println("For example:");
         System.out.println("");
         System.out.println("   RLReadFile mySystem");
         System.out.println("");
         System.out.println("");
         System.out.println("Note, this program reads data base file QIWS/QCUSTCDT.  ");
         System.out.println("");
         System.out.println("");
      }

      System.exit(0);

   }
}