When I use team1.addLiteral() before team1.getPropertyValue(), it does not give me Null error.
On Tue, Nov 8, 2016 at 3:11 PM, Lorenz B. < [email protected]> wrote: > "Good" is very subjective and depends on your design decisions...it > would work, sure. > But, what is the problem with checking for NULL in your code? > > > Is it a good idea to use team1.addLiteral() before > team1.getPropertyValue() > > just to assign some value to the property? > > And then we can write team1.setPropertyValue() to assign the final value? > > > > > > On Mon, Nov 7, 2016 at 9:53 AM, Lorenz B. < > > [email protected]> wrote: > > > >>> I want to ask why data property value "win" does not have default zero > >>> value? If it was zero, team1.getPropertyValue() would not flush > exception > >>> error message? > >> Which exception do you mean? There is no exception thrown but NULL > >> returned. Please show the code and do not ignore this again. Andy also > >> asked you for code. > >> And as Adam said, information in RDF can be "unknown". Moreover, it is > >> schema-less, and it's not a relational database with default values. > >>> On Sun, Nov 6, 2016 at 4:44 PM, Lorenz B. < > >>> [email protected]> wrote: > >>> > >>>> Comments inline: > >>>>> Hi > >>>>> I want to get the property value and then add add/sum 2 for each team > >>>> with > >>>>> it. > >>>>> team1(win value +2) // value is 2 here > >>>>> team1(win value +2) // value is 4 here > >>>>> > >>>>> team.getPropertyValue(Win); > >>>>> //then next operation to get value and sum 2 > >>>>> > >>>>> But the issue is I get error as I have not set the value first. > >>>> Which "error" do you get? According to [1] it returns null if there > >>>> hasn't been a value set before. > >>>> Java allows for > >>>> > >>>> if(something) { > >>>> // do something > >>>> } > >>>> > >>>> [1] > >>>> https://jena.apache.org/documentation/javadoc/jena/ > >>>> org/apache/jena/ontology/OntResource.html# > getPropertyValue-org.apache. > >>>> jena.rdf.model.Property- > >>>>> But if I > >>>>> set value before get the value, the property "win" always show that > >> value > >>>>> and not after calculated value. > >>>>> Is there any way for this issue? > >>>> Using an Integer variable in Java that holds the value before if > exists, > >>>> else 0 ... ? > >>>> > >>>> -- > >>>> Lorenz Bühmann > >>>> AKSW group, University of Leipzig > >>>> Group: http://aksw.org - semantic web research center > >>>> > >>>> > >>>> > >> -- > >> Lorenz Bühmann > >> AKSW group, University of Leipzig > >> Group: http://aksw.org - semantic web research center > >> > >> > >> > -- > Lorenz Bühmann > AKSW group, University of Leipzig > Group: http://aksw.org - semantic web research center > >
