5250 Connect User’s Guide
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In this diagram, Logon Connection D is associated with four connections based on
four UIDs (user IDs or credentials: A-thru-F). One is in use; another (UID ‘F’) is
alive but not being used; and two are inactive but available (i.e., valid UIDs have
been assigned, so these two connections can be made live at any time).
How Many Pools Do I Need?
It’s possible for several different 5250 components to draw from the same
connection pool. It’s also possible for different components to draw from different
pools. This means different Logon Connections.
An important factor in deciding how many Logon Connection resources (in effect,
how many pools) your service needs is the number of different start screens (or
entry point screens) needed by the various components in your project. Suppose
Terminal Component A needs to begin its work at a particular starting screen in a
host application, but you’ve also designed another component—Terminal
Component B—that needs to start on a different screen. Components A and B will
need separate Logon Connections, and the separate Logon Connections will point
to separate Logon Components. (In any given connection pool, Composer objects
are shared in such a way that every user of the pool must start at the same screen.)
Pieces Required for Pooling
The combination of a Logon Connection, a Logon Component, and its Connection
Resource form the basis of a connection pool. Starting from the host layer and
working up the chain:
The Connection Resource defines the most basic parameters necessary for
establishing a connection with the host. When connection pooling is in
effect, runtime instances of this object are kept alive and reused.
The Logon Component defines the set of steps (actions) necessary to get to a
particular entry point in the host program. (At runtime, an instance of this
component will actually carry out those steps in order to arrive at, and
maintain ready-to-use, a particular screen location in the host program.)
When connection pooling is in effect, instances of this object are kept alive
and reused.
The Logon Connection is a special type of resource that contains all the
information needed to define a connection pool. This resource is designed to
encapsulate pool-management info and does not establish host connections
directly; instead, it delegates those responsibilities to the Logon Component
(which delegates them, in turn, to the appropriate Connection Resource).
