Learning Neo4j 3.x - Second Edition

Creating a function

This is not rocket science, a function is just a method in a Java class. This method must be annotated with @UserFunction and @Description (both in the org.neo4j.procedure package).

To start, let's create a function that returns true if the given parameter is an odd number, and its even counterpart. The source code is as follows:

package learningneo4j;import org.neo4j.procedure.Description;import org.neo4j.procedure.Name;import org.neo4j.procedure.UserFunction;public class OddEven {    @UserFunction    @Description("Returns true if the given number is odd")    public Boolean isOdd(@Name("number") Long number){        if(number!=null) return number%2==1;        else            return false;    }    @UserFunction    @Description("Returns true if the given number ...