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CICS INVOKE SERVICE - Service Invocation

CICS INVOKE SERVICE provides service invocation capabilities for programs and transactions. It enables programs to invoke services, manage service execution, and handle service processing in CICS environments.

What is CICS INVOKE SERVICE?

CICS INVOKE SERVICE is a command that allows programs to invoke services in the system. It provides service invocation capabilities, service execution management, and service processing for CICS applications.

Command Syntax

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EXEC CICS INVOKE SERVICE
    SERVICE(service-name)
    [PARAMETER(parameter-data)]
    [LENGTH(parameter-length)]
    [RESP(response-code)]
END-EXEC

Parameters

Required Parameters

  • SERVICE(service-name) - Name of service to invoke

Optional Parameters

  • PARAMETER(parameter-data) - Parameter data for service
  • LENGTH(parameter-length) - Length of parameter data
  • RESP(response-code) - Response code variable

Service Types

Business Services

Business service types

  • • ORDER SERVICE - Order processing services
  • • INVENTORY SERVICE - Inventory management services
  • • CUSTOMER SERVICE - Customer management services
  • • PAYMENT SERVICE - Payment processing services

System Services

System service types

  • • UTILITY SERVICE - System utility services
  • • MONITORING SERVICE - Monitoring services
  • • REPORTING SERVICE - Reporting services
  • • MAINTENANCE SERVICE - Maintenance services

Communication Services

Communication service types

  • • MESSAGE SERVICE - Message processing services
  • • DATA SERVICE - Data exchange services
  • • INTERFACE SERVICE - Interface services
  • • INTEGRATION SERVICE - Integration services

Processing Services

Processing service types

  • • BATCH SERVICE - Batch processing services
  • • REAL-TIME SERVICE - Real-time processing services
  • • DATA SERVICE - Data processing services
  • • TRANSACTION SERVICE - Transaction processing services

Programming Examples

Basic Service Invocation

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       IDENTIFICATION DIVISION.
       PROGRAM-ID. INVSRV01.
       DATA DIVISION.
       WORKING-STORAGE SECTION.
       01  SERVICE-NAME PIC X(8) VALUE 'ORDERSRV'.
       01  PARAMETER-DATA PIC X(100) VALUE 'ORDER123'.
       01  PARAMETER-LENGTH PIC S9(4) COMP VALUE 7.
       01  RESPONSE-CODE PIC S9(8) COMP.
       
       PROCEDURE DIVISION.
           DISPLAY 'Invoking service'
           DISPLAY 'Service: ' SERVICE-NAME
           DISPLAY 'Parameter: ' PARAMETER-DATA
           
           EXEC CICS INVOKE SERVICE
               SERVICE(SERVICE-NAME)
               PARAMETER(PARAMETER-DATA)
               LENGTH(PARAMETER-LENGTH)
               RESP(RESPONSE-CODE)
           END-EXEC
           
           IF RESPONSE-CODE = DFHRESP(NORMAL)
               DISPLAY 'Service invoked successfully'
           ELSE
               DISPLAY 'Service invocation failed'
           END-IF
           
           EXEC CICS RETURN END-EXEC.

Advanced Service Management

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       IDENTIFICATION DIVISION.
       PROGRAM-ID. INVSRV02.
       DATA DIVISION.
       WORKING-STORAGE SECTION.
       01  SERVICE-NAME PIC X(8).
       01  PARAMETER-DATA PIC X(100).
       01  PARAMETER-LENGTH PIC S9(4) COMP VALUE 100.
       01  RESPONSE-CODE PIC S9(8) COMP.
       01  INVOKE-COUNT PIC S9(2) COMP VALUE 0.
       01  MAX-INVOKES PIC S9(2) COMP VALUE 3.
       01  SRV-STATUS PIC X(1).
       01  SERVICE-LIST.
           05  SRV-ITEM OCCURS 3 TIMES.
               10  SRV-ID PIC X(8).
               10  SRV-TYPE PIC X(8).
               10  SRV-PARAMETER PIC X(50).
               10  SRV-STATUS PIC X(1).
       
       PROCEDURE DIVISION.
           PERFORM INITIALIZE-SERVICES
           PERFORM INVOKE-MULTIPLE-SERVICES
           
           EXEC CICS RETURN END-EXEC.
       
       INITIALIZE-SERVICES.
           MOVE 'ORDERSRV' TO SRV-ID(1)
           MOVE 'BUSINESS' TO SRV-TYPE(1)
           MOVE 'ORDER123' TO SRV-PARAMETER(1)
           MOVE 'INVENTORY' TO SRV-ID(2)
           MOVE 'BUSINESS' TO SRV-TYPE(2)
           MOVE 'INV001' TO SRV-PARAMETER(2)
           MOVE 'REPORTSRV' TO SRV-ID(3)
           MOVE 'SYSTEM' TO SRV-TYPE(3)
           MOVE 'RPT001' TO SRV-PARAMETER(3).
       
       INVOKE-MULTIPLE-SERVICES.
           PERFORM VARYING INVOKE-COUNT FROM 1 BY 1
               UNTIL INVOKE-COUNT > MAX-INVOKES
               
               MOVE SRV-ID(INVOKE-COUNT) TO SERVICE-NAME
               MOVE SRV-PARAMETER(INVOKE-COUNT) TO PARAMETER-DATA
               MOVE 50 TO PARAMETER-LENGTH
               PERFORM INVOKE-SINGLE-SERVICE
               
               IF RESPONSE-CODE = DFHRESP(NORMAL)
                   MOVE 'I' TO SRV-STATUS(INVOKE-COUNT)
                   DISPLAY 'Service ' INVOKE-COUNT ' invoked successfully'
               ELSE
                   MOVE 'F' TO SRV-STATUS(INVOKE-COUNT)
                   DISPLAY 'Service ' INVOKE-COUNT ' invocation failed'
               END-IF
           END-PERFORM.
       
       INVOKE-SINGLE-SERVICE.
           EXEC CICS INVOKE SERVICE
               SERVICE(SERVICE-NAME)
               PARAMETER(PARAMETER-DATA)
               LENGTH(PARAMETER-LENGTH)
               RESP(RESPONSE-CODE)
           END-EXEC.

Error Handling with Service Invocation

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       IDENTIFICATION DIVISION.
       PROGRAM-ID. INVSRV03.
       DATA DIVISION.
       WORKING-STORAGE SECTION.
       01  SERVICE-NAME PIC X(8) VALUE 'ORDERSRV'.
       01  PARAMETER-DATA PIC X(100) VALUE 'ORDER123'.
       01  PARAMETER-LENGTH PIC S9(4) COMP VALUE 7.
       01  RESPONSE-CODE PIC S9(8) COMP.
       01  RETRY-COUNT PIC S9(2) COMP VALUE 0.
       01  MAX-RETRIES PIC S9(2) COMP VALUE 3.
       01  SRV-INVOKE-SUCCESSFUL PIC X(1) VALUE 'N'.
       
       PROCEDURE DIVISION.
           PERFORM INVOKE-SERVICE-WITH-RETRY
           
           EXEC CICS RETURN END-EXEC.
       
       INVOKE-SERVICE-WITH-RETRY.
           PERFORM INVOKE-SERVICE
           
           IF RESPONSE-CODE NOT = DFHRESP(NORMAL)
               AND RETRY-COUNT < MAX-RETRIES
               ADD 1 TO RETRY-COUNT
               DISPLAY 'Retry ' RETRY-COUNT ' service invocation'
               PERFORM INVOKE-SERVICE-WITH-RETRY
           END-IF.
       
       INVOKE-SERVICE.
           EXEC CICS INVOKE SERVICE
               SERVICE(SERVICE-NAME)
               PARAMETER(PARAMETER-DATA)
               LENGTH(PARAMETER-LENGTH)
               RESP(RESPONSE-CODE)
           END-EXEC
           
           EVALUATE RESPONSE-CODE
               WHEN DFHRESP(NORMAL)
                   MOVE 'Y' TO SRV-INVOKE-SUCCESSFUL
                   DISPLAY 'Service invocation successful'
               WHEN DFHRESP(NOTAUTH)
                   DISPLAY 'Not authorized to invoke service'
               WHEN DFHRESP(INVREQ)
                   DISPLAY 'Invalid service invocation request'
               WHEN DFHRESP(SERVICEERR)
                   DISPLAY 'Service invocation error'
               WHEN DFHRESP(SERVICENOTFOUND)
                   DISPLAY 'Service not found'
               WHEN DFHRESP(SERVICEINUSE)
                   DISPLAY 'Service is in use'
               WHEN OTHER
                   DISPLAY 'Unexpected service invocation error'
           END-EVALUATE.

Service Management

Service Invocation

  • • Service Invoke - Invoke services
  • • Service Execution - Execute services
  • • Service Validation - Validate service state
  • • Service Monitoring - Monitor service status

Service Lifecycle

  • • Service Registration - Register services
  • • Service Invocation - Invoke services
  • • Service Execution - Execute services
  • • Service Cleanup - Clean up services

Service Monitoring

  • • Service Tracking - Track service usage
  • • Service Auditing - Audit service operations
  • • Service Reporting - Report service status
  • • Service Analysis - Analyze service patterns

Service Error Recovery

  • • Service Error Detection - Detect service errors
  • • Service Error Recovery - Recover from service errors
  • • Service Retry Mechanisms - Implement service retry logic
  • • Service Fallback Procedures - Use service fallback procedures

Error Handling

Common Response Codes

  • DFHRESP(NORMAL) - Service invocation successful
  • DFHRESP(NOTAUTH) - Not authorized to invoke service
  • DFHRESP(INVREQ) - Invalid service invocation request
  • DFHRESP(SERVICEERR) - Service invocation error
  • DFHRESP(SERVICENOTFOUND) - Service not found
  • DFHRESP(SERVICEINUSE) - Service is in use

Performance Considerations

Service Efficiency

  • • Optimize service operations - Use efficient service handling
  • • Minimize service overhead - Reduce service processing overhead
  • • Use service pooling - Implement service pooling
  • • Monitor service frequency - Track service invocation patterns

System Impact

  • • Monitor system impact - Track how service invocation affects the system
  • • Optimize service handling - Ensure efficient service processing
  • • Manage service usage - Monitor service consumption
  • • Track performance metrics - Monitor service handling performance

Best Practices

Service Invocation Best Practices

  • • Invoke services only when needed
  • • Implement proper error handling for service operations
  • • Validate service state before invoking
  • • Use appropriate service management techniques
  • • Monitor service invocation activities and performance
  • • Maintain service invocation audit trails
  • • Handle service invocation errors gracefully

Explain It Like I'm 5 Years Old

Think of CICS INVOKE SERVICE like asking for help:

  • • Need Help: "You need help with something" - Need to invoke service
  • • Ask for Help: "Ask someone to help you" - Invoke service
  • • Get Help: "Someone helps you" - Service invoked
  • • Use Help: "Use the help you got" - Service executes
  • • Finish Task: "Finish your task with help" - Service completes

Exercises

Exercise 1: Basic Service Invocation

Create a program that invokes a basic service.

Exercise 2: Advanced Service Management

Write a program that manages multiple service invocations.

Exercise 3: Error Handling

Implement comprehensive error handling for service invocation failures.

Related Concepts

Service Management

Managing system services

Service Invocation

Invoking services

Service Execution

Executing services

Service Monitoring

Monitoring services

Error Handling

Managing service errors