Standardized Software Interfaces in modelling business process:

Standardized interfaces to existing software systems are another means of
flexibility in business process management. A variety of techniques to specify
software interfaces are known from software engineering and software architectures.
It is a key concept to decouple the use of a software component from its
implementation, i.e., to hide implementation details from usage information,
following the information hiding principle.
In the context of business process management, standardized software interfaces
are of crucial importance in system workflows, and also in human
interaction workflows, since the overall process structure can be decoupled
from the implementation of particular activities realized by software components.
A flexible association of process activities with software systems allows us
to change the implementation of specific process activities without changing
the overall business process. There are two variations: the software system
realizing a particular activity can be defined at design time of the process or at
run time of the process instances.
In the original implementation, an inventory
management system is used to realize the Check Inventory activity, and an
order management system is used to realize the Store Order and the Prepare
Invoice activity.
We assume that an ERP system is deployed to provide the functionality
of the order management system and of the inventory management system in
an integrated, robust, and scalable manner.
By standardized software interfaces, the business process activities can use
the functionality of the new system without changing the business process.
This enhances the flexibility of the business process implementation, because
the realization of particular process activities can be changed without modifying
the business process.
This discussion describes an ideal setting, in which activity realizations
can easily be exchanged. However, specific properties of legacy systems make
the definition of clean, standardized interfaces cumbersome, because legacy
systems offer their functionality typically by proprietary and often not well
documented interfaces.
discussed in Chapter 2.
In addition, the granularity with which legacy systems provide functionality
often does not match the granularity required by the business process. In
particular, legacy systems often realize complex subprocesses rather than individual
activities in a business process. Sometimes, the processes realized by
legacy systems and the modelled business processes are not immediately comparable.
These issues have to be taken into account when software interfaces
to existing information systems are developed.
One option to solving this problem is developing software interfaces that
make available the functionality provided by legacy systems with a granularity
that allows reuse of functionality at a finer level of granularity. The granularity
should match the granularity required at the business process level.
Depending on the legacy system, its complexity, software architecture,
and documentation, as well as the availability of knowledgeable personnel,
the required effort can be very high. If the need for finer-grained granularity
and efficient reuse of functionality is sufficiently high, then partial or complete
reimplementation can be an optio