Copyright 2004 Digital Enterprise Research Institute. All rights reserved.

www.deri.org

WSMO4J – Logical Expression Extension

reto.krummenacher@deri.org, holger.lausen@deri.org

Background

• WSMO4J captures WSMO meta model and concrete language WSML (v0.2)

• Generic model (concepts, attributes, relations, (pre/post)-conditions, ...) can be refined by logical expressions

• Current Status: in WSMO4J object model for logical expression: java.lang.String

• Reasoning, logical processing require object model– Rewriting into other logical languages– Wrapper for reasoners– Manipulation on object level (i.e. By tools)

Logical Expression Object Model

• Simplicity• Implementation not yet optimized• Basic Idea:

– getOperator()

– getArgument()

• Example:– a and c[atr hasValue val]LogicalExpression

getOperator(): ANDgetArit(): 2getArgument(1): Atom(a)

getArgument(2): Molecule (c[atr hasValue val])

Integration with WSMO4J – Terms (I)

• How does logexp extension integrate with the Objects / Identifiers?– Logic view on model requires: everything is a term– WSMO API has more restrictive view (concepts must be

identified by IRI/Anonymous IDs)– E.g.: _date(2005,10,10) memberOf somethingElse

is perfactly valid within logexp, but not in WSMO4J

subclassing the relevant classes and let them inherit from org.wsmo.common.xyz;

Integration with WSMO4J – Terms (II)

Summary

• Logical Expression API is an extension to WSMO-API(and implementation)

• Users can switch „transparently“ between viewing them as strings or as object models

• Can be used to translate to different formalisms / reasoners

• Available:– Snapshot: http://wsmo4j.sourceforge.net/snapshot/– SourceCode: ext directoy of wsmo4j

Backup: Code example use it „transparently“ in WSMO4J

//create a logicalexpressionfactory:HashMap params = new HashMap();params.put(Factory.PROVIDER_CLASS,

"org.deri.wsmo4j.logexpression.LogicalExpressionFactoryImpl");LogicalExpressionFactory _leFactory = (LogicalExpressionFactory)

Factory.createLogicalExpressionFactory(createParams);

//use this _leFactory as replacement with standard factory:params = new HashMap();params.put(Parser.PARSER_WSMO_FACTORY,

Factory.createWsmoFactory(null));params.put(Parser.PARSER_LE_FACTORY, _leFactory);Parser p = Factory.createParser(params);