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From "Paul Fremantle" <pzf...@gmail.com>
Subject Re: SynapseObject - Reminder...
Date Thu, 02 Mar 2006 09:43:00 GMT
Mukund

I agree that name value pairs are not good enough. But compare these two
XMLs:

---------------------------------------------------------------------------------------------------------

<SynapseObject name="ConsumerIdentification">
  <SynapseObject name="consumer0">
    <Attribute name="CONSUMER_TYPE" type="String">GOLD</Attribute>
    <Attribute name="IP_ADDRESS_FROM" type="String">192.167.6.0</Attribute>
    <Attribute name="IP_ADDRESS_TO" type="String">192.168.6.255</Attribute>
        <Attribute name="HTTP_AUTH_USERNAME" type="String">john</Attribute>
        <Attribute name="WS_SEC_USERNAME" type="String">john</Attribute>
        <SynapseObject name="assignedService">
            <Attribute name="serviceid1"
type="String">stockQuote1</Attribute>
        </SynapseObject>
    </SynapseObject>
    <SynapseObject name="consumer1">
        <Attribute name="CONSUMER_TYPE" type="String">SILVER</Attribute>
        <Attribute name="IP_ADDRESS_FROM" type="String">192.168.6.255
</Attribute>
        <Attribute name="IP_ADDRESS_TO" type="String">192.167.6.255
</Attribute>
        <Attribute name="HTTP_AUTH_USERNAME" type="String">mary</Attribute>
        <Attribute name="WS_SEC_USERNAME" type="String">mary</Attribute>
        <SynapseObject name="assignedService">
            <Attribute name="serviceid1"
type="String">stockQuote</Attribute>
            <Attribute name="ip" type="String">192</Attribute>
        </SynapseObject>
    </SynapseObject>
</SynapseObject>

---------------------------------------------------------------------------------------------------------

<ConsumerIdentification>
   <Consumer type="GOLD" http_auth_username="john" ws_sec_username="paul"/>
         <ipaddress from="192.167.6.0" to="192.167.6.255"/>
         <assignedService id ="StockQuote1"/>
     </Consumer>
     <Consumer type="SILVER" http_auth_username="mary"
ws_sec_username="mary"/>
         <ipaddress from="192.167.6.0" to="192.167.6.255"/>
         <assignedService id ="StockQuote1" ip="192"/>
     </Consumer>
</ConsumerIdentification>

---------------------------------------------------------------------------------------------------------

The second is more readable, simpler and easier to modify. I'm certainly not
suggesting that we HAVE to use Schema, but the fact is that you CAN validate
with Schema whereas XML1 you cannot validate that the CI data is correct,
only that generic format is right. This is equivalent to XML well-formedness
checking which is much weaker.

Regarding point 2, I wasn't suggeting that every mediator writer had to make
an effort. There is no effort in doing reflection, because the code already
exists in our Axis2 framework. Please look at
org.apache.axis2.databinding.ADBBean
and
org.apache.axis2.databinding.util.BeanUtil

This simple code will automatically write a bean out as XML:

        QName q = new QName("http://fremantle.org", "SimpleBean" );
        StAXOMBuilder b = new
StAXOMBuilder((XMLStreamReader)BeanUtil.getPullParser(sb,q));
        OMElement el = b.getDocumentElement();
        System.out.println(el);

and this even simpler code will automatically read in a bean from XML using
ADB:

SimpleBean sb2 = (SimpleBean)BeanUtil.deserialize(SimpleBean.class,
omelement);

I urge you to take a look at the ADB framework.

Paul


On 3/2/06, Mukund Balasubramanian <mukund@infravio.com> wrote:
>
>  Paul:
>
>
>
> I don't believe this proposal is in any way in conflict with usage of true
> XML. It is merely to provide structure to an otherwise flat list of name
> value pairs.
>
>
>
> If you look at an average WSDD document (which supports only name value
> pairs) for the X-Broker, it looks phenomenally complex just because of the
> need to nest objects into one another.
>
>
>
> Also, the name-value pair concept has its uses – most importantly that as
> a simple meta-model, it is supported by a wide variety of platforms such as
> registries (tModels) and also property files.
>
>
>
> Please see my comments below in response to your specific queries:
>
>
>  ------------------------------
>
> *From:* Paul Fremantle [mailto:pzfreo@gmail.com]
> *Sent:* Thursday, March 02, 2006 5:27 AM
>
> *To:* synapse-dev@ws.apache.org
> *Subject:* Re: SynapseObject - Reminder...
>
>
>
> I still have problems with the SynapseObject proposal.
>
> 1) I think it is much simpler for administrators to use what I call "real"
> XML. In other words, if there is a ClientIdentification mediator, then we
> either use simpler type properties to configure it, or we create a new
> schema that defines the configuration of the ClientIdentification metadata.
> This has the benefit that you can use Schema validators to validate the XML
> as well as Schema aware editors to generate a GUI for editing the data.
>
> *ClientIdentification can still be a structured object and not necessarily
> a flat list. Just analyze the use case for a multi-object array of Clients
> with more than one identification scheme. I agree with the schema validation
> argument but the onus of creating XML Schema's for property formats,
> configuring the namespace and schemaLocation to validate and taking on the
> responsibility of Object Marshalling and Mapping is just too high.*
>
>
>
> 2) To make it easier for Mediator developers the schema can be converted
> into a Java object using ADB and XSD2Java. We can probably do this
> automatically using reflection if the bean is not a simple type but
> implements the ADB interface.
>
> *Of course they can. It just might not be worth the effort. *
>
>
>
> 3) If this model is not appropriate, you can easily write a
> MediatorFactory (aka ProcessorConfigurator) that parses the XML and
> populates the mediators data.
>
> *Again, the onus of reading and manipulating the DOM lying on the
> developer is not something I think is necessary.*
>
>
>
> 4) I personally haven't yet understood the use case for global data, but
> if there is one, then we should simply have a single model for referencing
> XML fragments. That way if two mediators want to use the same configuration
> data, then they can both refer to the same element. In fact, we could do
> this using the Resource model we already have.
>
> I know that what we have here is two different views on how to use XML.
> The SO proposal uses a generic XML format to store specific data, and
> therefore loses out on all the useful stuff that XML provides natively -
> schema validation, readability, tool support, etc.
>
> *The truth is that this is useful only as an EXTENSION to the NV model and
> NOT as a replacement for XML **J** *
>
> * *
>
>
>
> Paul
>
>  On 3/1/06, *Vikas* <vikas@infravio.com> wrote:
>
> Hi...
>
>
>
> 1) If main processor comes across an xml fragment of type SynapseObject in
> synapse.xml it needs to call a processor
>
>     (SynapseObjectProcessor maybe) to convert the xml fragment into a
> SynapseObject instance.
>
>
>
> 2) But we need a place holder for this instance, now the question is where
> to put it for further reference.
>
> From a scoping perspective, we can scope it at two levels
>
> a) specific to a mediator
>
> If it is specific to a mediator then we should extend the current mediator
> to have a member variable of type hashtable and appropriate getters and
> setters. We can  push the SynapseObject in the hashtable, this also allows
> the user to use any kind of object if in case they choose not to you
> SynapseObject.
>
> b) global.
>
> For global usages we can put synapseObject instances in the
> SynapseEnvironment which can be used by any part of synapse.
>
>
>
> The getters and setters might look up the hierarchy... Mediator's
> hashtable, then environment...
>
>
>
> ~Vikas.
>
>  ----- Original Message -----
>
> *From:* Saminda Abeyruwan <samindaa@gmail.com>
>
> *To:* synapse-dev@ws.apache.org
>
> *Sent:* Tuesday, February 28, 2006 11:20 AM
>
> *Subject:* Re: SynapseObject - Reminder...
>
>
>
> Hi,
>
> Please be kind enough clarify the following small questions.
>
> 1. As every element <foo/> in the synapse.xml maps to a FooMediator, how
> does <foo/> gets the info out of <synapseobject/>. ex: does it as follows?
> <foo>
>     <synapseobject name="xx">
>             <synapseobject xx="xx"/> [1..n]
>      </synapseobject>
> </foo>
>
> 2. Does every mediator get a reference to <synapseobject/> or a selected
> few such as <servicemediator/> or <classmediator/> get the reference to
> <synapseobject/>.
> 3. Synapse now has a <define name="some_name"/> mediator and this mediator
> can reference this by <refdefine ref="some_name"/>
> Is it possible to have a scenario as follows
>
> <synapse xmlns="http://ws.apache.org/ns/synapse">
>
>    <servicemediator service="service1">
>         <refdefine ref="customer_properties"/>
>    </service>
>
>    <classmeditator class="com.service.Service2>
>          <refdefine ref="customer_properties"/>
>    </classmediator>
>
>    <servicemediator service="service3">
>         <synapseobject>
>               <attribute name="url" type="STRING">http://%3c</attribute>
>               <synapseobject name="consumern">
>                   <attribute name="identifier"
> type="STRING">someID</attribute>
>                   <attribute name="priority" type="INTEGER">2</attribute>
>             </synapseobject>
>         </synapseobject>
>    </servicemediator>
>
>     <define name="customer_properties">
>          <!-- attribute to service 1-->
>          <synapseobject name="service1">
>               <attribute name="url" type="STRING">http://%3c</attribute>
>               <synapseobject name="consumer0">
>                   <attribute name="identifier"
> type="STRING">someID</attribute>
>                   <attribute name="priority" type="INTEGER">2</attribute>
>             </synapseobject>
>            <synapseobject name="consumer1">
>                 <attribute name="identifier"
> type="STRING">someID</attribute>
>                 <attribute name="priority" type="INTEGER">6</attribute>
>             </synapseobject>
>        </synapseobject>
>        <!-- attribute to service 2-->
>       <synapseobject name="service2">
>               <attribute name="url" type="STRING">http://%3c</attribute>
>               <synapseobject name="consumer0">
>                   <attribute name="identifier"
> type="STRING">someID</attribute>
>                   <attribute name="priority" type="INTEGER">2</attribute>
>             </synapseobject>
>            <synapseobject name="consumer1">
>                 <attribute name="identifier"
> type="STRING">someID</attribute>
>                 <attribute name="priority" type="INTEGER">6</attribute>
>             </synapseobject>
>        </synapseobject>
>     </define>
> </synapse>
>
> 4. As we agreed on, <synapseobject/> will be an extension, and what would
> be the way of integrating this in to Synapse at run time.
>
> Thank you
>
> Saminda
>
> On 3/27/06, *Vikas* <vikas@infravio.com> wrote:
>
> Hi,
>
>
>
> This is regarding the Synapse object proposed by me and Soumadeep...
>
>
>
> For convenience I am putting below the links for reference:
>
> <http://mail-archives.apache.org/mod_mbox/ws-synapse-dev/200602.mbox/%3cPOEHIPNLJGDMKMMBHILOAECICBAA.soumadeep@infravio.com%3e
> >
>
> and the source code has been available in the Scratch
>
> <http://svn.apache.org/repos/asf/incubator/synapse/trunk/scratch/infravio/synapse-SO
> >
>
>
>
> I feel that it an effective utility and have made use of it in a all the
> mediators that I would like to commit . It sure has made handling mediator's
> config data easier..
>
> Would be checking in the cleaned up code for SynapseObject as an
> extension...Which I guess is OK.
>
>
>
> Please let me know if anyone has any concerns about it??
>
>
>
> ~Vikas
>
>
>
>
>
>
> --
> Paul Fremantle
> VP/Technology, WSO2 and OASIS WS-RX TC Co-chair
>
> http://bloglines.com/blog/paulfremantle
> paul@wso2.com
>
> "Oxygenating the Web Service Platform", www.wso2.com
>



--
Paul Fremantle
VP/Technology, WSO2 and OASIS WS-RX TC Co-chair

http://bloglines.com/blog/paulfremantle
paul@wso2.com

"Oxygenating the Web Service Platform", www.wso2.com

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