Using the generated Java helper class in an application

The Java class created by the RecordClassGenerator class can be used as part of an existing Java application to construct or parse a byte array passed to or from an assembler application.

Each generated Java helper class contains two constructors that can be used to create an instance of the generated class. Also, individual public accessor methods are generated for each symbol in the assembler source code. These constructors and accessor methods enable you to either:

Create a new instance of the generated class then use the accessor methods to set the fields in the class and obtain a byte array that represents the fields you have set, ready to be used by the assembler program.
Create an instance of the generated class based on an existing byte array that was passed to the Java program from the assembler program. The accessor methods can then be used to obtain the values from fields in the byte array.

Constructing a new record

This example creates a new instance of the MyRecord class by using the zero argument constructor and uses the setClaimNumber() method to set a value for the CLAIM_NUMBER field. Other accessor methods might then be used to set the other fields in the record. When all the fields are set, then the getByteBuffer() method is used to obtain a byte array that is in the correct format to be used as input to the assembler program.


MyRecord rec = new MyRecord();
String claimnum = "0000000000123456789";
rec.setClaimNumber(claimnum);
byte[] record = rec.getByteBuffer();

Creating a record from an existing byte array

If the Java program already has access to a byte array that contains data from the assembler program, then it can be used within the MyRecord class constructor to create an instance of the MyRecord class, which represents the data within the array. The Java program can use the getClaimNumber() method to obtain the value of the field within the byte array and manipulate it as necessary.


byte[] record;
MyRecord rec = new MyRecord(record);
String  claimnum = rec.getClaimNumber();

Usage of the Data Access Accelerator Library

You can use the methods in the IBM® Data Access Accelerator (DAA) library to improve performance when your Java™ code manipulates native data. For more information, see Native data operations in the IBM SDK documentation.

The AssemblerDatatypeFactory in a generated record will detect if DAA is available at run time and will create a DAA-enabled set of instances from the com.ibm.jzos.fields.daa package, which will leverage DAA under the covers to optimize the conversion of numerical data within a byte array to and from numerical Java objects. This support is dynamically enabled if the underlying DAA support is available in the IBM SDK at runtime. DAA can be disabled by setting the system property com.ibm.jzos.fields.use-daa explicitly to false.