Interface Literal

    • Method Detail

      • getLanguageTag

        java.util.Optional<java.lang.String> getLanguageTag()
        If and only if the datatype IRI is http://www.w3.org/1999/02/22-rdf-syntax-ns#langString, the language tag for this Literal is a non-empty language tag as defined by BCP47.
        If the datatype IRI is not http://www.w3.org/1999/02/22-rdf-syntax-ns#langString, this method must return Optional.empty().

        The value space of language tags is always in lower case; although RDF implementations MAY convert all language tags to lower case, safe comparisons of language tags should be done using String.toLowerCase(Locale) with the locale Locale.ROOT.

        Implementation note: If your application requires Serializable objects, it is best not to store an Optional in a field. It is recommended to use Optional.ofNullable(Object) to create the return value for this method.

        Returns:
        The Optional language tag for this literal. If Optional.isPresent() returns true, the value returned by Optional.get() must be a non-empty language tag string conforming to BCP47.
        See Also:
        RDF-1.1 Literal language tag
      • equals

        boolean equals​(java.lang.Object other)
        Check it this Literal is equal to another Literal.
        Literal term equality: Two literals are term-equal (the same RDF literal) if and only if the two lexical forms, the two datatype IRIs, and the two language tags (if any) compare equal, character by character. Thus, two literals can have the same value without being the same RDF term.
        As the value space for language tags is lower-space, if they are present, they MUST be compared character by character using the equivalent of String.toLowerCase(java.util.Locale) with the locale Locale.ROOT.

        Implementations MUST also override hashCode() so that two equal Literals produce the same hash code.

        Specified by:
        equals in interface RDFTerm
        Overrides:
        equals in class java.lang.Object
        Parameters:
        other - Another object
        Returns:
        true if other is a Literal and is equal to this
        See Also:
        Object.equals(Object)
      • hashCode

        int hashCode()
        Calculate a hash code for this Literal.

        The returned hash code MUST be equal to the result of Objects.hash(Object...) with the arguments getLexicalForm(), getDatatype(), getLanguageTag().map(s->s.toLowerString(Locale.ROOT)).

        This method MUST be implemented in conjunction with equals(Object) so that two equal Literals produce the same hash code.

        Specified by:
        hashCode in interface RDFTerm
        Overrides:
        hashCode in class java.lang.Object
        Returns:
        a hash code value for this Literal.
        See Also:
        Object.hashCode(), Objects.hash(Object...)