Java Reference
In-Depth Information
Java component
JMS
OSGi component
SCA
connector
Java
component
SOAP over HTTP
C++
component
Figure 11.1
SCA systems consist of components connected by bindings.
SCA
allows a range of component types and bindings. We've already seen the
OSG
i
component type in section 10.6 (where it was cunningly disguised as an implementa-
tion of the Remote Services Specification). Other component types include the
SCA
Java component type, whose components resemble normal Java classes with some
SCA
-
specific annotations, the
BPEL
component type, a Spring component type, and even
C++ and Python component types. These components can be bound together using
web services,
JMS
,
EJB
protocols, Comet,
ATOM
,
JSON-RPC
, or a default
SCA
communi-
cation binding (see figure 11.2).
Most of the
SCA
bindings, like web services, aren't
SCA
-specific, and this allows
SCA
-
based applications to communicate with external applications that haven't even heard
Web
services
JMS
BPEL
C++
OSGi
JSON-RPC
EJB
session
bean
ATOM
Python
Java
SCA
COMET
Endpoints
Connector types
Figure 11.2
SCA provides a toolkit of component types and a toolkit of connectors that can be mixed
and matched to bind endpoints together. The component types and bindings we show here aren't an ex-
haustive list, not least because SCA is extensible.
