Package net.sf.tweety.logics.dl.parser

Class DlParser

  • public class DlParser
extends Parser<DlBeliefSet,​DlAxiom>
    This class implements a parser for the description logic ALC (attributive concept language with complements). The input syntax is based on the input syntax of the Racer reasoner.
    Note: Racer is built for the description logic SRIQ(D) (= the DL that corresponds to the OWL2 language), which is more expressive than ALC. SRIQ(D)-exclusive elements like inverse roles, role hierarchies and at-least restrictions are not supported by this parser. Furthermore, the syntax of universal and existential restrictions is different for reasons of simplification (see BNF).

    The input syntax for an ALC knowledge base is given by the following BNF (starting symbol is KB):
    KB ::== SIGNATURE FORMULAS
    SIGNATURE ::== "signature(" (CONCEPT_DECLAR)? (ROLE_DECLAR)? (INDIVIDUAL_DECLAR)? ")"
    CONCEPT_DECLAR ::== ("\n")* "atomic-concepts(" (CONCEPTNAME)* ")"
    ROLE_DECLAR ::== ("\n")* "roles(" (ROLENAME)* ")"
    INDIVIDUAL_DECLAR ::== ("\n")* "individuals(" (CONSTANTNAME)* ")"
    AXIOMS ::== ("\n" AXIOM)*
    AXIOM ::== "instance " " " CONSTANTNAME " " CONCEPT | "related " CONSTANTNAME " " CONSTANTNAME " " ROLENAME |
    "implies " " " CONCEPT " " CONCEPT | "equivalent" CONCEPT " " CONCEPT
    CONCEPT ::== "(" CONCEPT ")" | CONCEPTNAME | "not " CONCEPT | "*top*" | "*bottom*" | "top" | "bottom" |
    "and " CONCEPT " " CONCEPT | "or " CONCEPT " " CONCEPT |
    "forall " ROLENAME " " CONCEPT | "exists " ROLENAME " " CONCEPT

    where CONCEPTNAME, ROLENAME, CONSTANTNAME are sequences of
    symbols from {a,...,z,A,...,Z,0,...,9} with a letter at the beginning
    excluding {"top","bottom"}.
    Author:
    Anna Gessler, Matthias Thimm

    • Field Summary

      Fields 
      Modifier and Type Field Description
      private java.lang.Boolean addTrueEquivalence
      A flag that is used for adding an additional formula to represent a (true) equivalence axiom.
      private DlSignature signature
      Keeps track of the signature.

    • Constructor Summary

      Constructors 
      Constructor Description
      DlParser()  

    • Method Summary

      Modifier and Type Method Description
      DlSignature getSignature()
      Returns the signature of this parser.
      private DlAxiom parseAxiom​(java.util.List<java.lang.Object> l)
      Parses an ALC axiom as a list of String tokens or formulas.
      DlBeliefSet parseBeliefBase​(java.io.Reader reader)
      Parses the given reader into a belief base of the given type.
      private ComplexConcept parseConcept​(java.lang.Object s)
      Parses an atomic concept, top concept or bottom concept from a String token.
      private ComplexConcept parseConcept​(java.util.List<java.lang.Object> l)
      Parses a complex concept as a list of String tokens or formulas.
      DlAxiom parseFormula​(java.io.Reader reader)
      Parses the given reader into a formula of the given type.
      private Individual parseIndividual​(java.lang.Object s)
      Parses an individual from a String token.
      private AtomicRole parseRole​(java.lang.Object s)
      Parses a role from a String token.
      private void parseTypeDeclaration​(java.lang.String s, DlSignature signature)
      Parses an atomic concept declaration of the form "concept" "(" CONCEPTNAME ")" or an atomic role declaration of the form "role" "(" ROLENAME ")" and modifies the given signature accordingly.
      void setSignature​(DlSignature signature)
      Sets the signature for this parser.
      void tokenize​(java.util.Stack<java.lang.Object> stack, int c)
      This method reads one character from the given reader and appropriately tokenizes it.

      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

    • Field Detail

      • signature

        private DlSignature signature
        Keeps track of the signature.

      • addTrueEquivalence

        private java.lang.Boolean addTrueEquivalence
        A flag that is used for adding an additional formula to represent a (true) equivalence axiom.

    • Constructor Detail

      • DlParser

        public DlParser()

    • Method Detail

      • parseBeliefBase

        public DlBeliefSet parseBeliefBase​(java.io.Reader reader)
                            throws java.io.IOException,
                                   ParserException
        Description copied from class: Parser
        Parses the given reader into a belief base of the given type.
        Specified by:
        parseBeliefBase in class Parser<DlBeliefSet,​DlAxiom>
        Parameters:
        reader - a reader
        Returns:
        a belief base
        Throws:
        java.io.IOException - if some IO issue occurred.
        ParserException - some parsing exceptions may be added here.

      • parseTypeDeclaration

        private void parseTypeDeclaration​(java.lang.String s,
                                  DlSignature signature)
        Parses an atomic concept declaration of the form "concept" "(" CONCEPTNAME ")" or an atomic role declaration of the form "role" "(" ROLENAME ")" and modifies the given signature accordingly.
        Parameters:
        s - a string
        signature - a signature

      • parseFormula

        public DlAxiom parseFormula​(java.io.Reader reader)
                     throws java.io.IOException,
                            ParserException
        Description copied from class: Parser
        Parses the given reader into a formula of the given type.
        Specified by:
        parseFormula in class Parser<DlBeliefSet,​DlAxiom>
        Parameters:
        reader - a reader
        Returns:
        a formula
        Throws:
        java.io.IOException - if some IO issue occurred.
        ParserException - some parsing exceptions may be added here.

      • tokenize

        public void tokenize​(java.util.Stack<java.lang.Object> stack,
                     int c)
        This method reads one character from the given reader and appropriately tokenizes it.
        Parameters:
        stack - used for monitoring the read items
        c - token from stream

      • parseAxiom

        private DlAxiom parseAxiom​(java.util.List<java.lang.Object> l)
        Parses an ALC axiom as a list of String tokens or formulas.
        Parameters:
        l - list of String tokens or description logic formulas
        Returns:
        a DLAxiom
        Throws:
        ParserException - if the list could not be parsed.

      • parseConcept

        private ComplexConcept parseConcept​(java.util.List<java.lang.Object> l)
        Parses a complex concept as a list of String tokens or formulas.
        Parameters:
        l - list of String tokens or description logic formulas
        Returns:
        a ComplexConcept
        Throws:
        ParserException - if the list could not be parsed.

      • parseIndividual

        private Individual parseIndividual​(java.lang.Object s)
        Parses an individual from a String token.
        Parameters:
        s - identifier of the individual
        Returns:
        an Individual
        Throws:
        ParserException - if the individual could not be parsed

      • parseConcept

        private ComplexConcept parseConcept​(java.lang.Object s)
        Parses an atomic concept, top concept or bottom concept from a String token.
        Parameters:
        s - String identifier of the concept
        Returns:
        a ComplexConcept
        Throws:
        ParserException - if the concept could not be parsed

      • parseRole

        private AtomicRole parseRole​(java.lang.Object s)
        Parses a role from a String token.
        Parameters:
        s - identifier of the role
        Returns:
        an AtomicRole
        Throws:
        ParserException - if the role could not be parsed

      • setSignature

        public void setSignature​(DlSignature signature)
        Sets the signature for this parser.
        Parameters:
        signature - a DL signature.

      • getSignature

        public DlSignature getSignature()
        Returns the signature of this parser.
        Returns:
        the signature of this parser.