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CICS GET CONTAINER (CHANNEL) - Channel Container Retrieval

CICS GET CONTAINER (CHANNEL) provides channel container retrieval capabilities for programs and transactions. It enables programs to retrieve data from channel containers, access channel data, and handle channel container operations in CICS environments.

What is CICS GET CONTAINER (CHANNEL)?

CICS GET CONTAINER (CHANNEL) is a command that allows programs to retrieve data from channel containers. It provides channel data access capabilities, container management, and channel container handling for CICS applications.

Command Syntax

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EXEC CICS GET CONTAINER
    CHANNEL(channel-name)
    CONTAINER(container-name)
    INTO(data-area)
    LENGTH(data-length)
    [RESP(response-code)]
END-EXEC

Parameters

Required Parameters

  • CHANNEL(channel-name) - Name of channel containing the container
  • CONTAINER(container-name) - Name of container to retrieve
  • INTO(data-area) - Data area to receive container data
  • LENGTH(data-length) - Length of data area

Optional Parameters

  • RESP(response-code) - Response code variable

Channel Container Types

Data Containers

Containers with application data

  • • APPLICATION DATA - Retrieve application data container
  • • BUSINESS DATA - Retrieve business data container
  • • TRANSACTION DATA - Retrieve transaction data container
  • • PROCESS DATA - Retrieve process data container

Control Containers

Containers with control information

  • • CONTROL DATA - Retrieve control data container
  • • STATUS DATA - Retrieve status data container
  • • CONFIGURATION DATA - Retrieve configuration data container
  • • METADATA - Retrieve metadata container

Message Containers

Containers with message data

  • • MESSAGE DATA - Retrieve message data container
  • • NOTIFICATION DATA - Retrieve notification data container
  • • ALERT DATA - Retrieve alert data container
  • • EVENT DATA - Retrieve event data container

Custom Containers

User-defined containers

  • • CUSTOM DATA - Retrieve custom data container
  • • USER DATA - Retrieve user data container
  • • WORKFLOW DATA - Retrieve workflow data container
  • • INTEGRATION DATA - Retrieve integration data container

Programming Examples

Basic Channel Container Retrieval

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       IDENTIFICATION DIVISION.
       PROGRAM-ID. GETCONTAINERCHANNEL01.
       DATA DIVISION.
       WORKING-STORAGE SECTION.
       01  CHANNEL-NAME PIC X(8) VALUE 'MAINCHAN'.
       01  CONTAINER-NAME PIC X(8) VALUE 'DATACON1'.
       01  DATA-AREA PIC X(100).
       01  DATA-LENGTH PIC S9(8) COMP VALUE 100.
       01  RESPONSE-CODE PIC S9(8) COMP.
       01  CONTAINER-RETRIEVED PIC X(1) VALUE 'N'.
       
       PROCEDURE DIVISION.
           IF CONTAINER-RETRIEVED = 'N'
               DISPLAY 'Retrieving container: ' CONTAINER-NAME
               DISPLAY 'From channel: ' CHANNEL-NAME
               
               EXEC CICS GET CONTAINER
                   CHANNEL(CHANNEL-NAME)
                   CONTAINER(CONTAINER-NAME)
                   INTO(DATA-AREA)
                   LENGTH(DATA-LENGTH)
                   RESP(RESPONSE-CODE)
               END-EXEC
               
               IF RESPONSE-CODE = DFHRESP(NORMAL)
                   MOVE 'Y' TO CONTAINER-RETRIEVED
                   DISPLAY 'Container retrieved successfully'
                   DISPLAY 'Container data: ' DATA-AREA(1:DATA-LENGTH)
               ELSE
                   DISPLAY 'Failed to retrieve container'
               END-IF
           ELSE
               DISPLAY 'Container already retrieved'
           END-IF
           
           EXEC CICS RETURN END-EXEC.

Advanced Channel Container Management

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       IDENTIFICATION DIVISION.
       PROGRAM-ID. GETCONTAINERCHANNEL02.
       DATA DIVISION.
       WORKING-STORAGE SECTION.
       01  CHANNEL-NAME PIC X(8) VALUE 'MAINCHAN'.
       01  CONTAINER-NAME PIC X(8).
       01  DATA-AREA PIC X(200).
       01  DATA-LENGTH PIC S9(8) COMP VALUE 200.
       01  RESPONSE-CODE PIC S9(8) COMP.
       01  CONTAINER-COUNT PIC S9(2) COMP VALUE 0.
       01  MAX-CONTAINERS PIC S9(2) COMP VALUE 5.
       01  CONTAINER-LIST.
           05  CONTAINER-ITEM OCCURS 5 TIMES.
               10  CONTAINER-ID PIC X(8).
               10  CONTAINER-STATUS PIC X(1).
       
       PROCEDURE DIVISION.
           PERFORM RETRIEVE-MULTIPLE-CHANNEL-CONTAINERS
           
           EXEC CICS RETURN END-EXEC.
       
       RETRIEVE-MULTIPLE-CHANNEL-CONTAINERS.
           MOVE 'CONTAIN1' TO CONTAINER-ID(1)
           MOVE 'CONTAIN2' TO CONTAINER-ID(2)
           MOVE 'CONTAIN3' TO CONTAINER-ID(3)
           MOVE 'CONTAIN4' TO CONTAINER-ID(4)
           MOVE 'CONTAIN5' TO CONTAINER-ID(5)
           
           PERFORM VARYING CONTAINER-COUNT FROM 1 BY 1
               UNTIL CONTAINER-COUNT > MAX-CONTAINERS
               
               MOVE CONTAINER-ID(CONTAINER-COUNT) TO CONTAINER-NAME
               PERFORM RETRIEVE-SINGLE-CHANNEL-CONTAINER
               
               IF RESPONSE-CODE = DFHRESP(NORMAL)
                   MOVE 'R' TO CONTAINER-STATUS(CONTAINER-COUNT)
                   DISPLAY 'Retrieved: ' CONTAINER-NAME
               ELSE
                   MOVE 'F' TO CONTAINER-STATUS(CONTAINER-COUNT)
                   DISPLAY 'Failed: ' CONTAINER-NAME
               END-IF
           END-PERFORM.
       
       RETRIEVE-SINGLE-CHANNEL-CONTAINER.
           EXEC CICS GET CONTAINER
               CHANNEL(CHANNEL-NAME)
               CONTAINER(CONTAINER-NAME)
               INTO(DATA-AREA)
               LENGTH(DATA-LENGTH)
               RESP(RESPONSE-CODE)
           END-EXEC.

Error Handling with Channel Container Retrieval

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       IDENTIFICATION DIVISION.
       PROGRAM-ID. GETCONTAINERCHANNEL03.
       DATA DIVISION.
       WORKING-STORAGE SECTION.
       01  CHANNEL-NAME PIC X(8) VALUE 'TESTCHAN'.
       01  CONTAINER-NAME PIC X(8) VALUE 'TESTCON'.
       01  DATA-AREA PIC X(50).
       01  DATA-LENGTH PIC S9(8) COMP VALUE 50.
       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  RETRIEVAL-SUCCESSFUL PIC X(1) VALUE 'N'.
       
       PROCEDURE DIVISION.
           PERFORM RETRIEVE-CHANNEL-CONTAINER-WITH-ERROR-HANDLING
           
           EXEC CICS RETURN END-EXEC.
       
       RETRIEVE-CHANNEL-CONTAINER-WITH-ERROR-HANDLING.
           PERFORM RETRIEVE-CHANNEL-CONTAINER
           
           IF RESPONSE-CODE NOT = DFHRESP(NORMAL)
               AND RETRY-COUNT < MAX-RETRIES
               ADD 1 TO RETRY-COUNT
               DISPLAY 'Retry ' RETRY-COUNT ' retrieving channel container'
               PERFORM RETRIEVE-CHANNEL-CONTAINER-WITH-ERROR-HANDLING
           END-IF.
       
       RETRIEVE-CHANNEL-CONTAINER.
           EXEC CICS GET CONTAINER
               CHANNEL(CHANNEL-NAME)
               CONTAINER(CONTAINER-NAME)
               INTO(DATA-AREA)
               LENGTH(DATA-LENGTH)
               RESP(RESPONSE-CODE)
           END-EXEC
           
           EVALUATE RESPONSE-CODE
               WHEN DFHRESP(NORMAL)
                   MOVE 'Y' TO RETRIEVAL-SUCCESSFUL
                   DISPLAY 'Channel container retrieved successfully'
               WHEN DFHRESP(NOTFND)
                   DISPLAY 'Channel or container not found'
               WHEN DFHRESP(NOTAUTH)
                   DISPLAY 'Not authorized to retrieve container'
               WHEN DFHRESP(INVREQ)
                   DISPLAY 'Invalid container request'
               WHEN DFHRESP(CONTAINERERR)
                   DISPLAY 'Container retrieval error'
               WHEN OTHER
                   DISPLAY 'Unexpected error occurred'
           END-EVALUATE.

Channel Container Management

Container Access

  • • Container Authorization - Control container access permissions
  • • Container Validation - Validate container requests
  • • Container Limits - Enforce container access limits
  • • Container Policies - Implement container access policies

Container Monitoring

  • • Container Tracking - Track container access activities
  • • Container Logging - Log container operations
  • • Container Auditing - Audit container access requests
  • • Container Reporting - Generate container access reports

Container Lifecycle

  • • Container Creation - Create new channel containers
  • • Container Initialization - Initialize channel containers
  • • Container Processing - Process channel container data
  • • Container Cleanup - Clean up channel container resources

Error Recovery

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

Error Handling

Common Response Codes

  • DFHRESP(NORMAL) - Channel container retrieved successfully
  • DFHRESP(NOTFND) - Channel or container not found
  • DFHRESP(NOTAUTH) - Not authorized to retrieve container
  • DFHRESP(INVREQ) - Invalid container request
  • DFHRESP(CONTAINERERR) - Container retrieval error
  • DFHRESP(CONTAINERMANAGEMENTERR) - Container management error

Performance Considerations

Container Efficiency

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

System Impact

  • • Monitor system impact - Track how containers affect the system
  • • Optimize container handling - Ensure efficient container processing
  • • Manage container usage - Monitor container consumption
  • • Track performance metrics - Monitor container handling performance

Best Practices

Channel Container Management Best Practices

  • • Retrieve channel containers only when needed
  • • Implement proper error handling for container operations
  • • Validate container requests before processing
  • • Use appropriate container access methods
  • • Monitor container access activities and performance
  • • Maintain container audit trails
  • • Handle container errors gracefully

Explain It Like I'm 5 Years Old

Think of CICS GET CONTAINER (CHANNEL) like getting a toy from a toy box:

  • • Find Toy Box: "Find the right toy box" - Locate channel
  • • Open Toy Box: "Open the toy box" - Access channel
  • • Find Toy: "Find the toy you want" - Locate container
  • • Take Toy: "Take the toy out" - Retrieve container data
  • • Play with Toy: "Play with the toy" - Use container data

Exercises

Exercise 1: Basic Channel Container Retrieval

Create a program that retrieves a specific container from a channel.

Exercise 2: Advanced Channel Container Management

Write a program that manages multiple channel container retrievals.

Exercise 3: Error Handling

Implement comprehensive error handling for channel container retrieval failures.

Related Concepts

Channel Management

Managing system channels

Container Management

Managing channel containers

Channel Data Access

Accessing channel data

Container Operations

Channel container operations

Error Handling

Managing container errors