Streaming Topic Maps API

Streaming Topic Maps API An event-based API to create topic maps Lars Heuer <heuer@semagia.com> TMRA 2008, Leipzig · 17.10.2008

Introduction TMAPI is the Document Object Model (DOM) for Topic Maps Even if TMAPI is Topic Maps engine independent, a deserializer would be TMAPI dependent TMAPI is programming language dependent (even if TMAPI 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)) © 2008 Lars Heuer · http://www.semagia.com TMRA 2008, Leipzig · 17.10.2008 3

Overview A parser notifies a handler about events IMapHandler interface provides notification methods for all TMDM facets: startTopicMap endTopicMap startTopic endTopic startAssociation endAssociation startReifier endReifier ... (32 callback methods) © 2008 Lars Heuer · http://www.semagia.com TMRA 2008, Leipzig · 17.10.2008 4

Architecture CTM Parser XTM Parser N3 Parser CSV Parser … Parser sends events to IMapHandler implemented by TMAPI RDF API … API © 2008 Lars Heuer · http://www.semagia.com TMRA 2008, Leipzig · 17.10.2008 6

Details IMapHandler provides 32 callback methods to cover all aspects of TMDM Each TMDM construct is introduced by a \"start\" event and terminated by an \"end\" event Subject identifiers, subject locators and item identifiers are reported as absolute IRIs (strings) IRefs are used for \"startTopic(ref)\" and \"topicRef(ref)\" notifications, they provide the absolute IRI (string) and the kind of identity IMapHandler provides nested events (i.e. startTopic followed by another startTopic event) iff the events cannot be misinterpreted © 2008 Lars Heuer · http://www.semagia.com TMRA 2008, Leipzig · 17.10.2008 8

Details IMapHandler is reponsible to detect merging situtations Parser simply fires events and forgets afterwards IMapHandler usually keeps a stack of objects / states to interpret the events correctly Events are sometimes context dependent, i.e. \"start/endType\", \"start/endScope\", \"start/endReifier\", … © 2008 Lars Heuer · http://www.semagia.com TMRA 2008, Leipzig · 17.10.2008 9

Details – Parsing Example EricClapton – \"Eric Clapton\". created(creator: EricClapton, work: JustOneNight) startTopic(ItemIdentifier http://example.org/map#EricClapton) © 2008 Lars Heuer · http://www.semagia.com TMRA 2008, Leipzig · 17.10.2008 11

Details – Parsing Example EricClapton – \"Eric Clapton\". created(creator: EricClapton, work: JustOneNight) value(\"Eric Clapton\") © 2008 Lars Heuer · http://www.semagia.com TMRA 2008, Leipzig · 17.10.2008 13

Details – Parsing Example EricClapton – \"Eric Clapton\". created(creator: EricClapton, work: JustOneNight) endName() endTopic() © 2008 Lars Heuer · http://www.semagia.com TMRA 2008, Leipzig · 17.10.2008 14

Details – Parsing Example EricClapton – \"Eric Clapton\". created(creator: EricClapton, work: JustOneNight) startAssociation() startType() topicRef(ItemIdentifier http://example.org/map#created) endType() © 2008 Lars Heuer · http://www.semagia.com TMRA 2008, Leipzig · 17.10.2008 15

Details – Parsing Example EricClapton – \"Eric Clapton\". created(creator: EricClapton, work: JustOneNight) startRole() startType() topicRef(ItemIdentifier http://example.org/map#creator) endType() © 2008 Lars Heuer · http://www.semagia.com TMRA 2008, Leipzig · 17.10.2008 16

Details – Parsing Example EricClapton – \"Eric Clapton\". created(creator: EricClapton, work: JustOneNight) startPlayer() topicRef(ItemIdentifier http://example.org/map#EricClapton) endPlayer() endRole() © 2008 Lars Heuer · http://www.semagia.com TMRA 2008, Leipzig · 17.10.2008 17

Details – Parsing Example EricClapton – \"Eric Clapton\". created(creator: EricClapton, work: JustOneNight) ... other role endAssociation() © 2008 Lars Heuer · http://www.semagia.com TMRA 2008, Leipzig · 17.10.2008 18

Details – SimpleMapHander Parser has to send a lot of start/end events Some syntaxes do not provide nested topics etc. SimpleMapHandler is a wrapper around any IMapHandler implemention SimpleMapHandler provides additional methods like \"type(IRef ref)\", \"player(IRef ref)\", \"reifier(IRef ref)\"… These events are translated to the common IMapHandler callback methods Example: player(IRef) startPlayer(), topicRef(IRef), endPlayer() Simplifies parser development © 2008 Lars Heuer · http://www.semagia.com TMRA 2008, Leipzig · 17.10.2008 20

Details – MIO Framework MIO (Map Input / Output) is built around the IMapHandler and provides a Service Provider Interface for registering IDeserializers All IDeserializers use the IMapHandler for event notification Discovery of a suitable IDeserializer by file extension, media type Introduces 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 © 2008 Lars Heuer · http://www.semagia.com TMRA 2008, Leipzig · 17.10.2008 21

Conclusions / Outlook Simplifies parser development because the parser simply fires events and does not care about merging constraints etc. IMapHandler concept has been implemented in Java, Python (Mappa) and PHP (QuaaxTM) IMapHandler and MIO (Map Input/Output) will become Open Source soon Streaming Topic Maps API should be controlled / adapted by the community (i.e. by the TMAPI project) © 2008 Lars Heuer · http://www.semagia.com TMRA 2008, Leipzig · 17.10.2008 22

References TMAPI http://www.tmapi.org/ TMAPI 2.0 http://www.tmapi.org/2.0/ tinyTiM TMAPI 1.0 / TMAPI 2.0 Topic Maps engine http://tinytim.sourceforge.net/ Mappa Python Topic Maps engine (not finished) http://mappa.googlecode.com/ MIO (Map I/O) http://mio.semagia.com/ QuaaxTM http://quaaxtm.sourceforge.net/ © 2008 Lars Heuer · http://www.semagia.com TMRA 2008, Leipzig · 17.10.2008 23

Streaming Topic Maps API

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Notes on slide 1

1 Event