Figure 2 shows a COBOL program, CLIENT1, that:.
copybook INQINTC
* Channel name
01 INQUIRY-CHANNEL PIC X(16) VALUE 'inqcustrec'.
* Container names
01 CUSTOMER-NO PIC X(16) VALUE 'custno'.
01 BRANCH-NO PIC X(16) VALUE 'branchno'.
01 CUSTOMER-RECORD PIC X(16) VALUE 'custrec'.
* Define the data fields used by the program
01 CUSTNO PIC X(8).
01 BRANCHNO PIC X(5).
01 CREC.
02 CUSTNAME PIC X(80).
02 CUSTADDR1 PIC X(80).
02 CUSTADDR2 PIC X(80).
02 CUSTADDR3 PIC X(80).
Note that the same COBOL copybook, INQINTC, is used by both the client and server programs. Line 3 and lines 5 through 7 of the copybook represent the INQUIRY-CHANNEL and its containers. These lines are not strictly necessary to the working of the programs, because containers and channels are created simply by being named (on, for example, PUT CONTAINER commands); they do not have to be defined. However, the inclusion of these lines in the copybook used by both programs makes for easier maintenance; they record the names of the containers used.
It is recommended that for ease of maintenance of a client/server application that uses a channel, create a copybook that records the names of the containers used and defines the data fields that map to the containers. Include the copybook in both the client and the server program.
IDENTIFICATION DIVISION.
PROGRAM-ID. CLIENT1.
WORKING-STORAGE SECTION.
COPY INQINTC
PROCEDURE DIVISION.
MAIN-PROCESSING SECTION.
*
* INITIALISE CUSTOMER RECORD
*
... CREATE CUSTNO and BRANCHNO
*
* GET CUSTOMER RECORD
*
EXEC CICS PUT CONTAINER(CUSTOMER-NO) CHANNEL(INQUIRY-CHANNEL)
FROM(CUSTNO) FLENGTH(LENGTH OF CUSTNO)
END-EXEC
EXEC CICS PUT CONTAINER(BRANCH-NO) CHANNEL(INQUIRY-CHANNEL)
FROM(BRANCHNO) FLENGTH(LENGTH OF BRANCHNO)
END-EXEC
EXEC CICS LINK PROGRAM('SERVER1')
CHANNEL(INQUIRY-CHANNEL) END-EXEC
EXEC CICS GET CONTAINER(CUSTOMER-RECORD) CHANNEL(INQUIRY-CHANNEL)
INTO(CREC) END-EXEC
*
* PROCESS CUSTOMER RECORD
*
... FURTHER PROCESSING USING CUSTNAME and CUSTADDR1 etc...
EXEC CICS RETURN END-EXEC
EXIT.
Figure 3 shows the SERVER1 program linked to by CLIENT1. SERVER1 retrieves the data from the custno and branchno containers it has been passed, and uses it to locate the full customer record in its database. It then creates a new container, custrec, on the same channel, and returns the customer record in it.
Figure 3 shows a simple example of a linked to program that retrieves data from the channel it has been passed. This program is linked-to by program CLIENT1 shown in Figure 2.
IDENTIFICATION DIVISION.
PROGRAM-ID. SERVER1.
WORKING-STORAGE SECTION.
COPY INQINTC
PROCEDURE DIVISION.
MAIN-PROCESSING SECTION.
EXEC CICS GET CONTAINER(CUSTOMER-NO)
INTO(CUSTNO) END-EXEC
EXEC CICS GET CONTAINER(BRANCH-NO)
INTO(BRANCHNO) END-EXEC
... USE CUSTNO AND BRANCHNO TO FIND CREC IN A DATABASE
EXEC CICS PUT CONTAINER(CUSTOMER-RECORD)
FROM(CREC)
FLENGTH(LENGTH OF CREC) END-EXEC
EXEC CICS RETURN END-EXEC
EXIT.