Developers use Service Flow Modeler to
define a combination of elements or characteristics that describe how the
adapter service will run in the CICS® Service Flow Runtime environment
to process requests.
Deployment patterns vary depending on the characteristics of the adapter
service and the nature of the request. For example, an adapter service of
a complex business transaction could require access to multiple target applications
and might result in data being updated. While an adapter service of a simple
business transaction could require access to only a single target application
and might result in no data being updated (a simple inquiry request for example).
The differences between simple and complex adapter services mean that different
processing patterns are used at run time.
Deployment patterns manifest in the modeled adapter service at build time.
Single connector simple patterns
A single connector pattern
consists of a single generated and deployed server adapter program as modeled
in
Service Flow Modeler to compose an adapter
service. The server adapter program can consist of one or more interactions
with multiple target systems, but does not require an Adapter Navigator to
manage request processing. This pattern is intended to support simple screen-sequencing
if the server adapter type is FEPI or Link3270, or where a distributed programming
link is invoked using a DPL server adapter. Only one server adapter can be
generated in a single connector pattern.
WebSphere® MQ server adapters, the
DPL server adapter that is generated with version 7 of the tooling, and the
Web services server adapter are not supported in a single connector
pattern.
There are two single connector patterns:
- Nonpersistent single connector pattern
- The term nonpersistent indicates that no record is written
to the BTS repository data set to reserve the name of the BTS process. This
is implemented using the BTS NOCHECK option on the BTS
DEFINE PROCESS command. Using this option improves BTS performance
by removing the need to write to the repository and its associated logging.
It also requires little if any BTS configuration.
- Persistent single connector pattern
- The term persistent means that a record is written to the
BTS repository data set to reserve the name of the BTS process. In this pattern,
the BTS NOCHECK option is not specified on the BTS
DEFINE PROCESS command. Omitting this option ensures that the context
of the adapter service (the request and reply data, as well as an intermediate
state data) is persistent through a failure.
Aggregate connector complex patterns
An aggregate connector
pattern consists of multiple generated and deployed server adapter programs
as modeled in
Service Flow Modeler to compose
an adapter service. Each server adapter program can consist of one or more
interactions with multiple target systems. This pattern also includes the
use of a generated and deployed adapter Navigator to mediate and control the
flow of the adapter service. During adapter service request processing, multiple
server adapters can be run without requiring action by the service requestor.
There
are two aggregate connector patterns:
- Nonpersistent single connector pattern
- The term nonpersistent indicates that no record is written
to the BTS repository data set to reserve the name of the BTS process. This
is implemented using the BTS NOCHECK option on the BTS
DEFINE PROCESS command. Using this option improves BTS performance
by removing the need to write to the repository and its associated logging.
It also requires little if any BTS configuration.
- Persistent single connector pattern
- The term persistent means that a record is written to the
BTS repository data set to reserve the name of the BTS process. In this pattern,
the BTS NOCHECK option is not specified on the BTS
DEFINE PROCESS command. Omitting this option ensures that the context
of the adapter service (the request and reply data, as well as an intermediate
state data) is persistent through a failure.
Passthrough pattern
In addition to the single and aggregate
patterns, a passthrough processing pattern is also supported to run target CICS transactions
using the CICS Link3270
bridge mechanism only. Passthrough processing refers to the programmatic functions
coded in, and managed by the service requestor in order to fulfill a business
transaction using the CICS Link3270 bridge mechanism. The BTS NOCHECK option
is always used for passthrough processing.
Although developers do not model
or deploy passthrough processing as an adapter service in Service Flow Modeler,
it is included here for clarity as it is neither a single connector nor aggregate
connector pattern.
See the CICS External Interfaces Guide Version
2 Release 2 or higher for information regarding the Link3270 bridge
mechanism and related processing.