Hi Kim
I do not understand your response below and still cannot understand what
"context-name" does even after reading the "Configuration guide" again ?
Well I agree with your comments about the POJO mediator, and usually the
samples are the ones more easier to understand by new users by looking
at working examples - but in this case we need a sample that illustrates
all the options.
What is meant by context-name is the name of a property set on the
message context. For example if you used the property mediator before in
a sequence, then you can pass that value into the setter of a POJO. The
setters only support simple types such as String, XML, boolean, int etc.
In addition to a property name, you could also pass in a XPath
expression, in which case its evaluated result value is passed. If you
could show a sample request message, and what you want passed into the
POJO, we could tell you exactly what you could do.
e.g.
<property name="mcPropertyName" value="value1"/>
<pojoCommand name="SomeClass">
<property name="stringConstant" value="value2"/> |
<property name="username" context-name="mcPropertyName" [action=(ReadContext |
UpdateContext | ReadAndUpdateContext)]>
(either literal or XML child)
</property> |
<property name="password" expression="//password" [action=(ReadMessage |
UpdateMessage | ReadAndUpdateMessage)]/>
</pojoCommand>
The above does this:
1) Create a new instance of SomeClass for each invocation. (Note - if
this is an issue, you must use the Class mediator instead)
2) call "setStringConstant()" passing the literal string "value2"
3) call "setUsername()" passing in value1 read from the context property
variable named "mcPropertyName"
4) call "setPassword()" passing in the result of the XPath evaluation of
"//password" on the current message payload
5) call execute() method of the POJO
6) call getters - see below
Now, depending on the Read/Update/ReadAndUpdate, either only the setters
will get called on the POJO before the execute(),
or only getters from the POJO would be called after execute(), and the
results set back as message context properties into
the message or to the payload at the XPath evaluated node, or both
setters followed by execute() and then the getters would
be called as per above.
You must understand that when people write software It is very clear to
them how it works. However outsiders have no idea. Encapsulation only
works when the contract (API) is well explained. So My dilemma (and many
other people trying to use synapse) is that I am trying to understand
Synapse, from the outside, but I do not have access to the knowledge
required. At the moment this knowledge only resides in the Synapse
Authors heads (and in the low level code).
Yes, I do understand you, 3 years back I was new to open source too, and
came from an enterprise software development background. With limited
documentation around than the expensive commercial equivalents, users
must be able to work a bit cooperatively with other users and developers
to solve any specific issue they encounter.
On previous ApacheCon/SOAWorld conferences I've covered some of the
basics of Synapse, and Paul has done some sessions as well. Tutorial
sessions are accepted only if a quorum confirms attendance at these
events - and I would do a tutorial at the next ApacheCon in the US if
people are interested. I have also been thinking about writing a book on
Synapse for quite sometime, but the time I have for this is limited
especially now since I work as an independent consultant, and need to
support my family, in addition to making voluntary contributions :-)
Our development team uses many open source products here. I am not being
critical but Synapse stands out in that a number of developers here have
looked at Synapse and have given up; not being able to comprehend it.
So it is hard for people to make contributions when they can't get past
square one. Maybe a solution is a Synapse beginners email list; so
people new to Synapse can ask these "obvious" questions until they
become expert enough to contribute.
With some/most open source projects one would not need any specialized
training most of the time - e.g. Tomcat (since its a standard servlet
engine), httpd etc.. however there are some projects that does require
some help, or where some help would save you loads of time. In my
experience Maven2 has been one such project. Take a look at the list of
sessions at the next ApacheCon sessions in Amsterdam in a few more days:
http://www.eu.apachecon.com/c/aceu2009/schedule/grid and you can see
quite a list of Apache projects, where some detailed help would
certainly save you time and money.
You could also consider custom training for your use of Synapse, since
your overall cost would still be much less as you save a lot on license
fees. "/During a training session with WSO2, the Concur team used the
"WSO2 ESB to replicate a data synchronization system in three hours that
the group had previously taken three weeks to build in Java/" [0] -
Training thus can really help you jump start your effort, and save your
team a lot of time - which actually results in a cost saving. There may
be others around locally in your area, but WSO2 as well as I, do provide
training and development support to help get started with Synapse.
I must also say that you must be able to deal with a bug or two, or an
enhancement sometimes, to fully support your use case. One nice example
is this [1] from about 2 years back with Synapse 1.0 on an old Sun
Solaris 5.9.. the user reported the issue, and we went from Synapse to
HttpComponents where the real issue was solved [2] with contributions
from quite a few people everywhere around, and help with testing from
the user which was crucial as no one else had a Solaris 5.9.. Now AFAIK
the US Army is happily using Synapse [3]
cheers
asankha
[0]
http://searchsoa.techtarget.com/news/article/0,289142,sid26_gci1334139,00.html
[1] http://markmail.org/message/4isn3ant5qol25q5
[2] http://markmail.org/message/naxxjbdhjnnxken4
[3] http://markmail.org/message/b67h6ggfh7vspt2u
--
Asankha C. Perera
AdroitLogic, http://adroitlogic.org
http://esbmagic.blogspot.com
