Contexts
The messaging APIs use processing contexts for organizing communication between an application and a Solace PubSub+ event broker. Contexts act as containers in which sessions are created and session-related events can be handled.
A context encapsulates threads that drive network I/O and message delivery notification for the sessions and session components associated with that context. For JCSMP, one thread is used for I/O and another for notification. For the Java RTO, C, and .NET APIs, a single thread is used for both I/O and for notification. The life cycle of a context‑owned thread is bound to the life cycle of the context. The Javascript and Node.js APIs are single threaded and have a single global context that is not exposed.
Typically, a context initializes and manages its own threads and file descriptors. However, the C API also allows client applications to drive the context’s main loop with their own application-thread. For more information, refer to C API Best Practices.
| PubSub+ Messaging API | Call or Property |
|---|---|
|
JCSMP |
com.solacesystems.jcsmp.Context |
|
Java RTO |
com.solacesystems.solclientj.core.handle.ContextHandle |
|
C |
solClient_context_create(...) solClient_opaqueContext_pt |
|
.NET |
SolaceSystems.Solclient.Messaging.ContextFactory SolaceSystems.Solclient.Messaging.IContext |
|
JavaScript and Node.js |
Not applicable |
The figure below shows the basic relationship between a context and its dependent processing components.
Overview of Core Concepts
