In this chapter, you learned a great deal about Pentaho Reporting Engine extension points. You learned the details of implementing a report expression, including defining the Expression
class, as well as all of the necessary metadata to view the expression in the Report Designer. With the RegexExpression
example, you were able to execute your own expression in the Report Designer. You also learned about report functions and how they differ from expressions.
Next, you learned how to implement your own formula functions, as well as the necessary metadata to execute the formula function within the Report Designer. You took the same regex example and placed it within the formula system. You then used the BSHExpression
to add your own custom code directly into a report within the Report Designer.
The chapter ended with an introduction to building report elements, and you created a star element that defines its own set of properties and renders different types of stars within reports.