Integration Guide

Customizing the PSS System Software
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WaveWorks PSS, Integration Guide, 1.10 Page 104
© 2000, Symbol Technologies, Inc. February 1, 2000
9. Customizing the PSS System Software
The WaveWorks PSS system offers a number of options for integrators that need to customize
the base system to meet customer requirements. PSS allows integrators to customize the system
by changing the DisplayServer scripts, writing custom services, or writing custom business
objects. PSS also supports “user exits,” which are function hooks in the base code that let the
integrator provide custom processing at key points in the code.
9.1 Custom DisplayServer Scripts
The DisplayServer process runs scripts called “interfaces” that control the display on RF devices
(terminals and RF entrance units). The code for the interfaces is stored in the WaveWorks
database. The source files that were used to load the database at install time are found (by
default) in the C:\PSS\StepDev folder. The integrator can make a customer-specific copy of
these source files and modify them as needed. The modifications can range from small changes
to the logic, such as running a custom transaction or changing the screen layout, to completely
rewriting the interface. Note that most interfaces get their text from the PSS database, so
changing the wording of prompt or message may be as simple as changing the text in the
PSS_Text table.
9.2 Custom Services
The PSS system uses NT Services (standalone processes that are started at bootup) to
communicate to hardware devices. Examples include the EhtService for communicating with
the RF entrance unit, PssPrinterXX for talking to serial ticket printers, and the PssPosService for
talking to the store’s POS system. Writing an NT service requires a solid programming
background and WaveWorks developer training, but is an option for providing an interface to
special devices or computer systems. The services connect to the WaveWorks MessageServer
and use WaveWorks transactions to access standard business services.
9.3 Custom Business Objects
PSS business services are contained in more than a dozen COM Objects. Each business service
is a COM object method. The WaveWorks system uses transaction Ids to map business services
to a particular method on a particular business object. Integrators don’t have access to the base
system source code (aside from user exits that are implemented in the COM Objects), but they
can create their own COM Objects. These COM Objects can provide new business services
(using new transaction Ids) or replace existing business services (by changing the mapping
between transaction ID and COM object/method in the WaveWorks database). These new
business services can be accessed from custom services and custom DisplayServer interfaces.