Using java function in select statement

Question

Hi,
I am trying to use java function in select statement.
public class ClassA{
     private static String MyConst = "foo";
     public static String functionA(){
          return MyConst;
in my query I have:
select
     ClassA.functionA() AS id,
     groupId AS newID,
from
     myChannel[now]
ClassA is part of the application (no need to import).
I get and error of Invalid Expression on ClassA.functionA().
I also tried to declare the function in the processor element:
<wlevs:processor id="proc">
     <wlevs:function function-name="A" exec-methode="functionA">
          <bean class="mtPackage.ClassA"/>
     </wlevs:function>
<wlevs:processor>
but then I get a different error in the processor XML file:  "An InvocationTargetException was encoutered while attemting to register the user defind function A. The message was null"
What am I missing here?

Answer 1

Hi,
From the above description, you have tried two manners to call method functionA() in the user defined  class ClassA. One uses java cartridge manner directly and the other try to use user defined function manner.
For the java cartridge manner, the following CQL query should work if the ClassA is really included in the OEP app. I have done similar test before, it works.
select
     ClassA.functionA() AS id,
     groupId AS newID,
from
     myChannel[now]
For user defined function manner, I think two things you need to change:
1. Need to declare the function in the EPN assembly file(under META-INF/spring/), not component configuration file(under META-INF/wlevs/). The following is an example:
<wlevs:processor id="proc">
     <wlevs:function function-name="A" exec-methode="functionA">
          <bean class="mtPackage.ClassA"/>
     </wlevs:function>
</wlevs:processor>
2. Call the user defined function in the CQL query in the component configuration file under processor. For example:
select A() from myChannel
Regards,
XiYing