> Yes its true that it returns Null Pointer Exception. It returns NULL, not a NullPointerException! That's totally different! > > But what you people suggest I suppose to do? One thing in my mind is to > include first: > employee.addLiteral(Property, 1) > Then employee.getPropertyValue() > Then Perform calculation/addition > And last, employee.setPropertyValue(Property, sum/calculated value). I don't know your programming skills, but this is more than obvious...
get the value - if this is NULL - simply set the new value - ELSE set the existing value + the new value > > On Mon, Oct 17, 2016 at 12:52 AM, Lorenz B. < > [email protected]> wrote: > >> Hello Tina, >> >> >> >> >>> I want to sum 5 with the value already stored in a property. >>> >>> //Property "Hours" must be started from 1 and then sum 5 with it. >>> employee.getPropertyValue(No_of_Hours); >>> //Then perform calculations. >>> >>> The problem is that if I directly use employee.getPropertyValue(), it >> gives >>> me "Exception" (and rightly, because I did not set setPropertyValue() >>> first). >> That's not true. It returns null if there is no such value - and you >> have to handle this in the code indeed. >>> But the problem is that when I set employee.getPropertyValue(No_ >> of_Hours); >>> to 1 (one), it will always set the value 1(one) and not the recent >>> added(sum) value in the property. >>> >>> employee.setPropertyValue(No_of_Hours, 1); //1 is literal >>> employee.getPropertyValue(No_of_Hours); >>> //calculations >>> My requirement is like: int sum=No_of_Hours+1; >>> Then No_of_Hours plus what in the *variable sum*. >>> >>> So can I use employee.addLiteral(No_of_Hours, 1) instead of >>> employee.setPropertyValue(). >>> >>> I hope you have understood what my issue is? >>> >>> Kindest regards >>> >>> >>> >>> On Sun, Oct 16, 2016 at 11:10 AM, Dave Reynolds < >> [email protected]> >>> wrote: >>> >>>> On 16/10/16 16:59, tina sani wrote: >>>> >>>>> Hi >>>>> >>>>> What is the difference between addLiteral() and setpropertyvalue() >> when we >>>>> want to assign values to an individual.? >>>>> For example, >>>>> >>>>> //myEmployee is an instance. >>>>> >>>>> myEmplyee.addliteral(property, value) >>>>> myEmployee.setpropertyvalue(property, value) >>>>> >>>>> >>>> addLiteral adds a value, so if there is already a value there you will >> now >>>> have multiple values. >>>> >>>> setPropertyValue removes all existing values before adding the new value >>>> so you will only have the new value at the end. >>>> >>>> Dave >>>> >>>> >> -- >> 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
