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There are a large number of CICS services
supported by LTP. Each LTP service is mapped to a J2EE service listed
below. If the J2EE mapped service is clustered in a particular
environment, then so too is the equivalent LTP service.
Recovery uses
the Java Transaction Service to handle transaction commits and rollbacks.
Basic Mapping
Support uses a Servlet as a terminal for HTML support, as do the Web,
TCP/IP and Document services.
Program Control
uses direct invocation within the presentation Servlet (within the same
task) or EJB session invocation. HTTP routing handles the
clustering of Servlet views, and the application server handles any
clustering of EJB session beans.
File Control
uses JDBC to access VSAM data that has been mapped into a database.
SQL
uses JDBC.
Transient Data and
Temporary Storage use JMS or internalized queues. The queue itself
should be clustered for maximum utility. Internal queues are small,
serialized collections stored in the HttpSession, often used for Temporary
Storage. The more heavyweight Transient Data queues generally use JMS
queues. The JMS implementation should support clustered queues.
Interval Control
uses JMS for invocation of LTP message beans (non-terminal based
transactions) using the START command. The JMS implementation should
support clustered queues.
Task Control and
Counter use JNDI for lightweight data sharing; both of these services
are rare. Task Control is for locking out other tasks from a particular
resource and should always be avoided where possible; our session based
queue options make this much simpler than in the original CICS. The
Counter service is similar, using shared integer counters. Both of these
services are shared to the level that JNDI is shared within the
application server implementation.
Journal, Spool,
Trace, Operator and Dump services use a variety of logging APIs or JMS
queues.
Security uses
JAAS. The same users should be visible across the cluster.
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