Summary

In previous chapters, we explored what Apex is and how applications are built using it. The examples were simple, Hello World style. In this chapter, we introduced the Apex library, which is of central importance to developing real-world applications. The library contains the functional building blocks that are required to integrate with existing data infrastructure and operators that implement the transformations that are frequently needed for the stream processing.

The chapter also provided links to documentation and example applications for the operators that were covered, which will be helpful as the starting point when building your own application (after all, it is much easier to start from something that works and build on top of it, as opposed to starting from scratch). Beyond functionality, we also saw how various operators support aspects such as low latency, performance, scalability, fault-tolerance, and processing guarantees that are required for production-quality applications...