The MediaSpaces Mapping Framework

The MediaSpaces Mapping Framework allows for the declaration of mapping relationships between incompatible vocabularies on the Web. It includes an extensible function framework to bridge heterogeneities also on the instance level. Mapping specifications are compiled into executable SPARQL query templates, which allows developer to set up executable SPARQL mediation endpoints in order to integrate metadata from different heterogeneous SPARQL data sources at run-time.

Overall Integration Scenario

For demonstration purposes we have set up a sample integration scenario including metadata from three heterogeneous metadata catalogs.

The scenario integrates the following data sources, which have all been wrapped using the OAI2LOD Server:

• http://www.mediaspaces.info:3110/ exposes Dublin Core metadata from the OAI-PMH repository of the National Library of Australia.
• http://www.mediaspaces.info:3120/ exposes MODS metadata from the Library of Congress OAI-PMH repository.
• http://www.mediaspaces.info:3130/ exposes metadata, which follow a proprietary metadata schema (vocabulary), from the Austrian National Libraries' Image Archive OAI-PMH repository.

Assuming that a client application needs to access these data sources by formulating queries using Dublin Core terms, we have set up a mediator component that integrates the three data sources:

• http://www.mediaspaces.info:3200/ provides uniform access to ONB, LOC, and LNA metadata and accepts SPARQL queries formulated over Dublin Core. For performance purposes it is strongly suggested to use LIMIT clauses when executing queries against http://www.mediaspaces.info:3200/sparql.

The following configuration is an excerpt of one of three mapping specifications used by the mediator. It maps the ONB vocabulary to Dublin Core:

  	
@prefix mm:		<http://www.mediaspaces.info/vocab/mapping/rdfs-mapping#> .
@prefix am:		<http://www.mediaspaces.info/vocab/mapping/abstract-mapping#> .
@prefix onb:		<http://www.mediaspaces.info/schemes/onb#> .
@prefix dc:		<http://purl.org/dc/elements/1.1/> .
@prefix fn:		<http://www.w3.org/2005/xpath-functions#> .
@prefix map:		<http://www.mediaspaces.info:3200/resource/mapping/onb_dc/> .

map:model a am:MappingModel ;
	am:sourceModel onb: ;
	am:targetModel dc: ;
	.

map:pm1 a mm:PropertyMapping;
	am:expression am:equivalent;
	am:sourceElement onb:title;
	am:targetElement dc:title;
	mm:sourceClassContext onb:Image;
	.

map:pm2 a mm:PropertyMapping;
	am:expression am:targetInclude;
	am:sourceElement onb:authorfirstname;
	am:sourceElement onb:authorlastname;
	am:targetElement dc:creator;
	am:transFunction map:fnlnConcat;
	.

map:fnlnConcat a am:Function;
	am:functionURI fn:concat;
	am:argument (onb:authorlastname ", " onb:authorfirstname);
	am:result dc:creator;
	.

map:pm4 a mm:PropertyMapping;
	am:expression am:sourceInclude;
	am:sourceElement onb:classification;
	am:targetElement dc:type;
	.

map:pm5 a mm:PropertyMapping;
	am:expression am:targetInclude;
	am:sourceElement onb:url;
	am:targetElement dc:identifier;
	.

map:pm6 a mm:PropertyMapping;
	am:expression am:targetInclude;
	am:sourceElement onb:mimeType;
	am:targetElement dc:format;
	.
		
	

map:pm2 is an example for a n-ary mapping relationship, which also includes an instance transformation function map:fnlnConcat that concatenates the onb:authorfirstname and onb:authorlastname instance values into a suitable representation for the dc:creator property.

Feature Overview

MediaSpaces Mapping Framework - release 0.1

• Specification of mapping relationships between RDF/S classes and properties.
• Instance transformation function framework.
• Conversion of mapping specifications into SPARQL query templates
• Instantiation of mediation components for the distributed execution of user queries.

Download and installation

The MediaSpaces Mapping Framework is available, both as source and binary, on sourceforge.net under the GNU General Public Licence (GPL) and should run on any platform that supports Java 1.5 or higher.

Binary installation

Linux / Mac OS

1. Download the mediaspaces-mapping-x.x.tar.gz file and untar (tar xfz mediaspaces-mapping-x-x.tar) it in any directory.

Windows

1. not tested yet, but it should work. There is a zip-file mediaspaces-mapping-x.x.zip with the same contents.

Installation from source

The MediaSpaces Mapping Framework sources are available at: https://mediaspaces.svn.sourceforge.net/svnroot/mediaspaces/mapping/. Use your SVN client to checkout the sources and run ant in the base directory to compile the release files.

Usage and Documentation

The best starting point are probably the test cases that are available under /test in the binary download package as well as in the SVN repository.

Here is the link to the online JavaDoc