16.9. Execution Context

The approach that ModeShape takes is simple: a simple POJO that represents everything about the environment in which components operate. Called ExecutionContext, it contains references to most of the essential facilities, including: security (authentication and authorization); namespace registry; name factories; factories for properties and property values; logging; and access to class loaders (given a classpath). Most of the ModeShape components require an ExecutionContext and thus have access to all these facilities.

The fact that so many of the ModeShape components take ExecutionContext instances gives us some interesting possibilities. For example, one execution context instance can be used as the highest-level (or application-level) context for all of the services (e.g., RepositoryService, SequencingService, etc.). Then, an execution context could be created for each user that will be performing operations, and that user's context can be passed around to not only provide security information about the user but also to allow the activities being performed to be recorded for user feedback, monitoring and/or auditing purposes.