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WebSphere Message Broker (or message broker for short) enjoys a second
class citizen status to many developers and architects - specially those
that come from WebSphere Application Server and/or J2EE background. It
took me a long time, many discussions and bunch of stressful and often
heated debates to convince one of my clients that the message broker is
and can be used as an ESB and it will work just fine with WebSphere
Process Server. If I had failed, they would have used WebSphere ESB for
all interactions with process server and message broker for everything
else, essentially resulting in 2 ESBs and potentially defeating the
purpose of the ESB. And this is not the only time I have seen this.
What amazes me is not the fact that people don't like message broker.
It's the reasons they give for not wanting to use it. In the rest of
this blog entry, I am going to list those reasons, which are really
myths, and dispel them.
Message broker has poor support for web service standards. WebSphere
ESB has better support. If you are focused on standards based
interactions using XML, SOAP and WS* then go with WebSphere ESB.
This is not true. Message broker supports web services standards as well
as if not better than WebSphere ESB:
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It has support for web services standards including Basic Profile 1.1,
see
http://publib.boulder.ibm.com/infocenter/wmbhelp/v6r1m0/topic/com.ibm.etools.mft.doc/ac55890_.ht
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In WS-* standards, it has support for WS-Addressing, see,
http://publib.boulder.ibm.com/infocenter/wmbhelp/v6r1m0/index.jsp?topic=/com.ibm.etools.mft.doc/ac64300_.htm
and WS-Security, see,
http://publib.boulder.ibm.com/infocenter/wmbhelp/v6r1m0/index.jsp?topic=/com.ibm.etools.mft.doc/ac55630_.htm
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On vanilla web services, message broker actually supports more SOAP
processing nodes than WebSphere ESB. Broker soap nodes are listed at:
http://publib.boulder.ibm.com/infocenter/wmbhelp/v6r1m0/index.jsp?topic=/com.ibm.etools.mft.doc/ab00026_.ht
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Message broker even supports SOAP/MTOM and integration with a registry
such as WSRR
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It has out of the box functionality to generate schema based messages
from WSDL, which WebSphere ESB doesn’t
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It even allows you to make any text based message a SOAP message, get
SOAP envelop in or out, get SOAP body out and so on – WebSphere ESB
supports this but it doesn't have this capability provided out of the
box in the development tool (integration developer
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It provides a lot of XML functionalities including XSLT that WebSphere
ESB provides. See this link to get a high level idea
http://publib.boulder.ibm.com/infocenter/wmbhelp/v6r1m0/index.jsp?topic=/com.ibm.etools.mft.doc/ac67160_.htm
Message broker requires you to use proprietary things like ESQL. So
code developed in message broker code becomes proprietary. WebSphere ESB
is based on J2EE and SCA (Service Component Architecture) those are both
standards. Mediations developed for WebSphere ESB could be ported to
another standard platform in the future
Again, this is not true.
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You can use ESQL or Java in message broker. While ESQL is proprietary,
Java is an open standard
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While SCA is a standard and some vendors are implementing it,
portability across containers is still a dream. Plus, not every vendor
wraps mediations in an SCA component. Also, packaging of SCA
components (in jar and ear files) appears to be specific to WebSphere
ESB and process server. In some cases, you have to extend a com.ibm
class or use a com.ibm class behind the scene (e.g. binding classes).
The point isn't that SCA is bad. The point is, although SCA is a
standard, use of SCA in WebSphere ESB doesn't make ESB code portable
If you have J2EE developer adoption of WebSphere ESB is easier than
message broker.
This argument does hold some water. WebSphere ESB is built on top of
WebSphere Application Server. It uses ear and jar as deployment
artifacts, it uses EJB and Web projects behind the scene. However, you
should keep in mind that there is a learning curve involved in using
WebSphere ESB as well. I would agree that the learning curve for a J2EE
developer on message broker would be steeper.
The point of this blog entry is not to say that message broker is better
than WebSphere ESB. Nor that the message broker should be chosen over
ESB. The intent is to dispel some myths so it is not discarded for wrong
reasons.
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