Streams, Windows, Adapters, and Continuous Queries in Projects

ESP projects are like applications, and consist 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:

Element	Description
Input streams and windows	Receives input data flowing 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	Connects an input stream or window to a datasource. ESP 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	Takes data from one or more streams or windows and applies a continuous query to produce a new stream or window. Derived streams that have state are windows.