How to Build a Business Rules Engine

This code is relatively simple, reasonably easy to read, and well commented. These

are all advantages that the designer should strive for.

Figure 15.2 illustrated the Investment screen, with which the defined rules are

associated in this example. If the user goes to that screen and adds a new record, and

then presses the Save button without entering any data, all the defined business rules

will detect errors. Figure 15.6 shows what happens.

With the design approach described here it only takes a couple of minutes to

define and implement the business rules needed to create the checks shown in Figure

15.6.

Design Review

This chapter has covered some fundamental ...