Preconditions and Postconditions:

Mapping of heterogeneous data is important in

any enterprise application
middleware. It provides the technical basis

for integrating services with each
other, so that the results returned by one

service can be used by follow-up
services.
The next level addresses the questions, about

under what conditions a
certain activity can be executed, and what the

result of an activity execution
is, i.e., preconditions and postconditions of

activities. Interestingly, in business
process modelling, preconditions and

postconditions are already captured. In
event-driven process chains, for instance,

preconditions and postconditions are
represented by events, although in a

relatively informal fashion.
For example, if the arrival of an order

message triggers an activity to
store the order, then an event order arrived

is connected by control flow to
a function store order. The outgoing edge of

this function is connected to an
event order is stored. The order arrived event

characterizes the precondition
of the function, This type of informally

specified precondition and postcondition of a

function
in a business process is suitable for

fostering the understanding of process
models by human stakeholders. To be usable for

composing services realized
by software, the preconditions and

postconditions need to be specified in a
more precise way.