Defining a client

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A program or method that requests services from one or more methods in a class is called a client of that class.

About this task

In a COBOL or Java™ client, you can:

  • Create object instances of Java and COBOL classes.
  • Invoke instance methods on Java and COBOL objects.
  • Invoke COBOL factory methods and Java static methods.

In a COBOL client, you can also call services provided by the Java Native Interface (JNI).

A COBOL client program consists of the usual four divisions:

Table 1. Structure of COBOL clients
Division Purpose Syntax
IDENTIFICATION (required) Name a client. Code as usual, except that a client program must be:
  • Thread-enabled (compiled with the THREAD option, and conforming to the coding guidelines for threaded applications)
ENVIRONMENT (required) Describe the computing environment. Relate class-names used in the client to the corresponding external class-names known outside the compilation unit.

CONFIGURATION SECTION (required)
REPOSITORY paragraph for defining a client (required)

DATA (optional) Describe the data that the client needs. DATA DIVISION for defining a client (optional)
PROCEDURE (optional) Create instances of classes, manipulate object reference data items, and invoke methods. Code using INVOKE, IF, and SET statements.

Example: defining a client

related tasks   
Compiling, linking, and running OO applications  
Preparing COBOL programs for multithreading  
Communicating with Java methods  
Coding interoperable data types in COBOL and Java  
Creating and initializing instances of classes  
Comparing and setting object references  
Invoking methods (INVOKE)  
Invoking factory or static methods

related references  
THREAD