Book Image

Pentaho Reporting 3.5 for Java Developers

Book Image

Pentaho Reporting 3.5 for Java Developers

Overview of this book

Pentaho Reporting lets you create, generate, and distribute rich and sophisticated report content from different data sources. Knowing how to use it quickly and efficiently gives you the edge in producing reports from your database. If you have been looking for a book that has plenty of easy-to-understand instructions and also contains lots of examples and screenshots, this is where your search ends. This book shows you how to replace or build your enterprise reporting solution from scratch with Pentaho's Reporting Suite. Through detailed examples, it dives deeply into all aspects of Pentaho's reporting functionalities, providing you with the knowledge you need to master report creation. This book starts off with a number of examples to get you familiar with the tools and technology of the Pentaho Reporting Suite. Then, with additional examples, it goes into advanced subjects such as charting, sub-reporting, cross tabs, as well as API generation of reports. There are also details and examples on extending Pentaho's open source reporting engine. The reader will learn the ins and outs of Pentaho Report Designer, including a cheat sheet with all the available short-cut keys, to make report design efficient and painless. Embedding reports into your Java application can be difficult. With Pentaho Reporting it's just a few lines of code. The book provides examples of how to embed reporting into your J2EE and client Java applications, as well as showing you how to build dynamic reports from scratch using Pentaho Reporting's simple Java Bean-based report generation API. Setting up and integrating a reporting server in an enterprise environment can be arduous. In addition to learning how to build great embeddable reports, you'll also learn how to combine Pentaho Reporting with Pentaho's BI Server for a zero-code, easy-to-configure, enterprise reporting solution.
Table of Contents (19 chapters)
Pentaho Reporting 3.5 for Java Developers
Credits
Foreword
About the Author
About the Reviewers
Preface
Index

Implementing BeanShell expressions


Another approach to implementing your own report expressions is using the BSHExpression report expression, which uses BeanShell to evaluate an expression. BeanShell is a Java code interpreter, so you can write Java for direct execution within a report with this expression. The BSHExpression contains a property called expression, which should contain the necessary BeanShell script. This script must contain the Object getValue() method, which is called to evaluate the expression. Imports and additional functions may be included in the expression. The expression also has access to the DataRow class instance named dataRow. This allows for easy access to the current row of data for the expression to use.

Example BSHExpression

Open up the already defined chapter11.prpt, defined earlier in this chapter, within Report Designer. Now add a Bean-Scripting-Host (BSH) expression, which is located within the Script function group. Set the expression property to the...