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ActiveXML peer

Anca GhitescuR&D Engineer - GEMO

19/05/2008

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Agenda

• ActiveXML peer– ActiveXML documents– Architecture– Activation: chain of execution– ActiveXML materializers– ActiveXML services– Continuous service calls– AXML syntax– Software components

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ActiveXML documents

- XML documents with

embedded calls to web services*sc = service call

- When activated, these documents are enriched with data coming as results of service calls

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ActiveXML example

• Before activation <example xmlns:axml="http://futurs.inria.fr/gemo/axml/"> <axml:sc axml:id="temperature"> <axml:ws-soap endpoint="http://webservices.daehosting.com/services/TemperatureConversions.wso"> <CelciusToFahrenheit><nCelcius>10</nCelcius></CelciusToFahrenheit> </axml:ws-soap> </axml:sc></example>

• After activation

<example xmlns:axml="http://futurs.inria.fr/gemo/axml/"> <axml:sc axml:id="temperature"> ... </axml:sc> <m:CelciusToFahrenheitResult >50</m:CelciusToFahrenheitResult></example>

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Architecture of ActiveXML system

• Peer-to-peer network: a collection of ActiveXML peers

• A peer: client/server functionality

• As client: – Materializes service calls inside the

document– Processes the results

• As server: axml specific web services– Materialization Service– Algebra Operators: Send, Receive,

NewNode– Continuous Query Service

• Repository for AXML documents

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Activation: Chain of execution

Activate the document version.xml@peer1 and get the data from peer2

example

sc [id="version";http://peer2/services/Version]

getVersion

version.xml@peer1 before activation

example

version 1.3

sc result

getVersion

version.xml@peer1 after activation

Client

Server

Materialization Service

version.xml

peer1

Client

ServerVersion

peer2

1. load document

Web Interface

2. call activate

3. use InOut MaterializerMaterializers 5. get response

4. call service

6. append data

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ActiveXML services

• Generic Query Service: applies a query over (continuous) data • Streaming Service: streams data from a file stored in the

database• Continuous Service: calls a service continuously• Optimax Service: rewrites axml documents based on rules

• Materialization Service: activates service calls inside axml documents

• Algebra Services: enable distributed data management– NewNodeOperator: installs axml data on remote peers– SendOperator: sends data (continuously)– ReceiveOperator: receives data

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ActiveXML Materializers

• Calling different services and processing the results• They might need to be specified into axml documents

depending on called services– DefaultOutOnlyMaterializer / DefaultOutInMaterializer – MaterializerForContinuousQuery: calls

GenericQueryService with parameters coming as results of other service calls (streams)

– MaterializerForContinuousSC: calls continuously a web service, each time a new parameter value arrives.

– MaterializerForSC: eliminates the sc declaration from active parameters of a service call and calls the parent web service

– MaterializerForRECEIVE / MaterializerForSEND

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Continuous service calls• A service is called with parameters coming from a stream• A stream might represent the results of another service call • ReceiveOperator is called to stream back the results

continuousQuery

declaration

sc [GenericQueryService;MaterializerForContinuousQuery]

let $a:= <param id="stream">for $r in $a/* return $r

param [id="stream"]

example

sc [StreamService] data1 data2

result1 result2

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AXML example: continuous query<example xmlns:axml="http://futurs.inria.fr/gemo/axml/">

<axml:sc axml:id="continuousFILTER">

<axml:return materializer=

"fr.inria.gemo.axml.model.sc.materialization.MaterializerForContinuousQUERY">

<axml:append/>

</axml:return>

<axml:ws-soap endpoint="http://localhost:6969/MyPeer/services/GenericQueryService">

<q:continuousQuery xmlns:q="http://futurs.inria.fr/gemo/axml/service/Query">

<q:declaration>

let $book := <q:param name="book"/>

for $b in $book/* return if(xs:integer($b/year) gt 2003) then $b else ()

</q:declaration>

<q:param name="book">

<axml:sc axml:id="bookStreamer">

...

</axml:sc>

<STREAM_DATA/>

</q:param>

</q:continuousQuery>

</axml:ws-soap>

</axml:sc>

</example>

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Generic Query Service

• Execute a query• Execute a continuous query (stream parameters)• Apply a public query defined in another document (as a

function)

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Optimax Service

• Optimizer for AXML documents• Rewrites the documents with the help of Algebra operators

(Send, Receive, NewNode)• Rewriting based on strategy and statistics

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AXML syntax

• XML schemas– the syntax of axml documents– the definition of axml services– the communication headers for SOAP messages

• A sc is uniquely identified by (peerID, docID, nodeID)• Activation order

– default: depth first – afterActivated, afterTerminated

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• Web server: Tomcat 5.5• Axis2 Web service engine• Repository: eXist XML database• ActiveXML engine• Web interface:

– GWT (Google Web Toolkit)– XForms

• SOAP Alerter

Software Components

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Miscellaneous

• www.activexml.net• Documentation• Regression Tests• SVN repository:

http://forge.objectweb.org/projects/activexml/

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Merci!