Java Reference
In-Depth Information
(continued)
Whether you choose to use an ESB or SCA will probably be determined by what tech-
nologies you're already using. SCA usually has a lower initial cost for connecting to-
gether two specific things, but an ESB may have lower long-term costs because it's
a more general-purpose solution to an infrastructure problem.
Java EE
application
Web
service
OSGi
bundle
JCA
OSGi service
SOAP over HTTP
Enterprise Service Bus
SOAP over HTTP
XSLT transform
OSGi service
JMS with XSLT transform
Enterprise
OSGi
bundle
Another
Java EE
application
.NET
application
Figure 11.4
An ESB acts as a common transport channel loosely connecting diverse endpoints. Com-
munications may be mediated with XSLT transforms or other adjustments to the content.
A number of
ESB
providers use
OSG
i for their internal architecture. But fewer of these
ESB
s include support for user's
OSG
i bundles, and fewer still include enterprise
OSG
i
support in their runtime. But you do have some choices if you want to use your enter-
prise
OSG
i application with an
ESB
.
APACHE SERVICEMIX
The most comprehensive enterprise
OSG
i support is arguably provided by Apache Ser-
viceMix. ServiceMix provides native hosting for your
OSG
i bundles and built-in Blue-
print support, based on Apache Aries. Some nice extensions mean Blueprint can even
be used to configure the message routing.
FUSE ESB
Closely related to ServiceMix is Fuse
ESB
, a productized offering of ServiceMix. Fuse
ESB
is still open source, but commercial support subscriptions are available.
APACHE KARAF PLUS APACHE CAMEL
ServiceMix is based on a combination of Apache Karaf and Apache Camel, with fea-
tures to handle security, registries, and extra configuration. Some users find they don't
