Controlling server interactions

A flow object—CclFlow—controls each interaction between the Client application and a server and determines the synchronization of reply processing; synchronous, deferred synchronous or asynchronous.

This example creates a synchronous flow object:

CclFlow sflow( Ccl::sync );

A flow object is referenced when a server request call is first issued and remains active from that time until all client processing of the corresponding reply from the server has been completed. At that point it is set inactive and becomes available for reuse or deletion. During its active lifespan, a flow object maintains the state of the client/server interaction it is controlling.

The flow class should be subclassed to provide the implementation of a reply handler which will be called when a reply is received; this happens regardless of the synchronization type. The reply handler is passed a buffer object which contains the communication area returned by the server. A default reply handler is provided; it just returns to the caller without doing anything.

Separate flow subclasses could be needed to cater for different client/server communication area protocols. Many flows can be active at the same time. Many servers can be used simultaneously by the same CICS® Transaction Gateway.


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Timestamp icon Last updated: Tuesday, 19 November 2013


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