streaming topic maps api

StreamingTopic Maps API

An event-based API to createtopic maps

Lars Heuer <[email protected]>

TMRA 2008, Leipzig · 17.10.2008

© 2008 Lars Heuer · http://www.semagia.com TMRA 2008, Leipzig · 17.10.2008 2

Table of Contents

IntroductionOverviewArchitectureDetailsOutlook


IntroductionTMAPI is the Document Object Model (DOM) forTopic MapsEven if TMAPI is Topic Maps engine independent, a deserializer would be TMAPI dependentTMAPI is programming language dependent (even ifTMAPI has been ported to several languages)Relative heavy API (a lot of factory methods)Streaming Topic Maps API uses a push model(more aligned to the Simple API for XML (SAX))


OverviewA parser notifies a handler about eventsIMapHandler interface provides notification methodsfor all TMDM facets:

startTopicMapendTopicMapstartTopicendTopicstartAssociationendAssociationstartReifierendReifier... (32 callback methods)


Architecture

IMapHandler

CTM Parser XTM Parser N3 Parser CSV Parser … Parser

sends events to


Architecture

IMapHandler

CTM Parser XTM Parser N3 Parser CSV Parser … Parser

TMAPI RDF API … API

sends events to

implemented by

N3 Parser


Details – IMapHandler


DetailsIMapHandler provides 32 callback methods to coverall aspects of TMDMEach TMDM construct is introduced by a "start" event and terminated by an "end" eventSubject identifiers, subject locators and itemidentifiers are reported as absolute IRIs (strings)IRefs are used for "startTopic(ref)" and "topicRef(ref)" notifications, they provide theabsolute IRI (string) and the kind of identityIMapHandler provides nested events (i.e. startTopicfollowed by another startTopic event) iff the eventscannot be misinterpreted


Details

IMapHandler is reponsible to detect mergingsitutationsParser simply fires events and forgetsafterwardsIMapHandler usually keeps a stack of objects/ states to interpret the events correctlyEvents are sometimes context dependent, i.e. "start/endType", "start/endScope", "start/endReifier", …


Details – Parsing ExampleEricClapton – "Eric Clapton".created(creator: EricClapton,

work: JustOneNight)



work: JustOneNight)

startTopic(ItemIdentifier http://example.org/map#EricClapton)



work: JustOneNight)

startName()



work: JustOneNight)

value("Eric Clapton")



work: JustOneNight)

endName()endTopic()



work: JustOneNight)

startAssociation()startType()topicRef(ItemIdentifier http://example.org/map#created)endType()



work: JustOneNight)

startRole()startType()topicRef(ItemIdentifier http://example.org/map#creator)endType()



work: JustOneNight)

startPlayer()topicRef(ItemIdentifier http://example.org/map#EricClapton)endPlayer()endRole()



work: JustOneNight)

endAssociation()

... other role


Details – Stackability

IMapHandler

IMapHandler IMapHandler

Parser

delegates to


Details – SimpleMapHanderParser has to send a lot of start/end eventsSome syntaxes do not provide nested topics etc.SimpleMapHandler is a wrapper around anyIMapHandler implementionSimpleMapHandler provides additional methods like"type(IRef ref)", "player(IRef ref)", "reifier(IRef ref)"…These events are translated to the commonIMapHandler callback methodsExample:player(IRef) startPlayer(), topicRef(IRef), endPlayer()Simplifies parser development


Details – MIO Framework MIO (Map Input / Output) is built around theIMapHandler and provides a Service Provider Interface for registering IDeserializersAll IDeserializers use the IMapHandler for eventnotificationDiscovery of a suitable IDeserializer by fileextension, media typeIntroduces some constraints: I.e. a subdeserializer(i.e. merging XTM encoded topic map into a CTM encoding topic map) must not send a start/endTopicMap event


Conclusions / OutlookSimplifies parser development because the parsersimply fires events and does not care about mergingconstraints etc.IMapHandler concept has been implemented in Java, Python (Mappa) and PHP (QuaaxTM)IMapHandler and MIO (Map Input/Output) will become Open Source soonStreaming Topic Maps API should be controlled / adapted by the community (i.e. by the TMAPI project)


ReferencesTMAPIhttp://www.tmapi.org/TMAPI 2.0http://www.tmapi.org/2.0/tinyTiMTMAPI 1.0 / TMAPI 2.0 Topic Maps enginehttp://tinytim.sourceforge.net/MappaPython Topic Maps engine (not finished)http://mappa.googlecode.com/MIO (Map I/O)http://mio.semagia.com/QuaaxTMhttp://quaaxtm.sourceforge.net/


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