CICS Container
Enhanced Definition
In CICS (Customer Information Control System), a container is a named, temporary data area used to pass data between CICS programs within a `channel`. It serves as a flexible and efficient mechanism for storing and transmitting application data, particularly for larger data structures or varying data types, overcoming the size limitations of traditional `COMMAREAs`.
Key Characteristics
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- Part of a Channel: Containers are always associated with a
channel, which is a named collection of one or more containers. A program can create multiple containers within a single channel. - Typed Data: Each container has a
type(e.g.,CHAR,BIT,DATETIME,POINTER), allowing CICS to manage data appropriately. Programs can store and retrieve data in various formats. - Temporary Storage: Containers are temporary and exist only for the duration of the
channel's scope (typically within a transaction or until explicitly deleted). They are held in CICSshared storageorauxiliary temporary storage. - Size Flexibility: Unlike
COMMAREAs(which are limited to 32KB), containers can hold significantly larger amounts of data, up to 2GB for a single container, making them suitable for complex data structures or XML/JSON documents. - Program Isolation: Data within a container is isolated from other containers and programs unless explicitly passed via a
channel, ensuring data integrity and preventing unintended side effects. - Language Agnostic: CICS containers can be used by programs written in various languages supported by CICS, such as
COBOL,PL/I,C/C++, andJava.
- Part of a Channel: Containers are always associated with a
Use Cases
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- Passing Large Data Between Programs: Used extensively for passing large data structures, arrays, or complex objects between CICS programs, especially when
COMMAREAsare insufficient. - Web Service Data Exchange: Facilitating the exchange of
XMLorJSONdata between CICS applications and external web services, where data volumes can be substantial. - Inter-Program Communication: Enabling modular application design by allowing different CICS programs (e.g., business logic, presentation layer, data access) to exchange specific data sets efficiently.
- Data Transformation: Storing intermediate results or transformed data during multi-step processing within a CICS transaction before final output or database updates.
- Passing Large Data Between Programs: Used extensively for passing large data structures, arrays, or complex objects between CICS programs, especially when
Related Concepts
Containers are intrinsically linked to CICS Channels, which act as the named collection holding them. They are a modern alternative and successor to COMMAREAs for inter-program communication, offering greater