...
Naturally, deep changes to the engine influence all other programms, which use JFreeReport. It is unavoidable that the changed API will be incompatible to any previously released version. As even minor API changes will break programms anyway, our development will follow that path with full-force, happily refactoring or removing all ugly code. Once the JFreeReport 0.9 release is feature complete, the API will be driven to stability. At that point, only show-stoppers or , complex features or bug-fixes will cause non-backward-compatible changes. Once JFreeReport reached reaches 1.0, the API will be frozen for long-term maintainance. At that point, JFreeReport's code will maintain backward compatibility at all costs.
Reports , which use the API to create the report definition from scratch, are will not be compatible with the new release. There will be no easy upgrade-path for these reports, as most classes referenced by that legacy code will be gone and the reporting logic will be changed radically. Applications, which use the XML definitions will enjoy an easier upgrade-path. A compatibility layer will be provided, which takes care of most of the gory details of transforming old report definitions into the new format. Of course, report definitions kept in the old format will not be able to use exciting new features.
...
JFreeReport 0.9 uses a completely different reporting approach. Instead of using the data as the control factor for the report process, JFreeReport concentrates on the layout that should be generated. In the new model, JFreeReport iterates over the layout (the report definition). The data processing is controlled by embedded data control commands, which control the iteration over the data sources.
By concentrating on the desired output format, now it is realitivly relatively easy to create reports, which are no longer bounds to the classical nested grouping structures. Groups are controlled by the defined data commands, and therefore it is possible to create paralell parallel or even irregular grouping structures.
...