6.5. Message Bus
Overview
Message bus refers to a messaging architecture, shown in Figure 6.5, “Message Bus Pattern”, that enables you to connect diverse applications running on diverse computing platforms. In effect, the Apache Camel and its components constitute a message bus.
Figure 6.5. Message Bus Pattern
The following features of the message bus pattern are reflected in Apache Camel:
- Common communication infrastructure — The router itself provides the core of the common communication infrastructure in Apache Camel. However, in contrast to some message bus architectures, Apache Camel provides a heterogeneous infrastructure: messages can be sent into the bus using a wide variety of different transports and using a wide variety of different message formats.
- Adapters — Where necessary, Apache Camel can translate message formats and propagate messages using different transports. In effect, Apache Camel is capable of behaving like an adapter, so that external applications can hook into the message bus without refactoring their messaging protocols.In some cases, it is also possible to integrate an adapter directly into an external application. For example, if you develop an application using Apache CXF, where the service is implemented using JAX-WS and JAXB mappings, it is possible to bind a variety of different transports to the service. These transport bindings function as adapters.
