An ESP project is like an application,
consisting of a set of event streams, any other required datasources, and the business logic
applied to incoming event data to produce results.
At its most basic level, a project consists of:
- Input streams and windows – where the input data flows into the project. An input
stream can receive incoming event data on an
event-driven basis, and can also receive static or semistatic sets of data
that are loaded once or periodically refreshed. Input streams that have
state—that is, they can retain and store data—are called windows.
- Adapters – connect an input stream or window to a datasource.
Event Stream Processor includes a large set of
built-in adapters as well as an SDK that you can use to build custom
adapters. Adapters can also connect an output stream or window to a
destination. While an adapter connects the project to external inputs and
outputs, technically it is not part of the project.
- Derived streams and windows – take data from one or more streams or windows and apply a
continuous query to produce a new
stream or window. Derived streams that have state are windows.