execute BIRT Script using BIRT API

Saed

hi all

I need your help to find a way to execute or evaluate BIRT Script using API !
I get the validate script as the following:

ParameterHandle paramHandle = (ParameterHandle) task.getParameterDefn("FromDate").getHandle();

String validateScript = paramHandle.getValidate();

this validateScript string is a Birt Script looks like the following script:

if (BirtComp.lessThan(params["FromDate"].value,params["ToDate"].value)) {
true;
}
else{
false;
}

I know that i can use :
boolean validate = task.validateParameters();
to execute all validation scripts for all parameters...

but I need to execute a specific script which is shown above.

Please tell me if there is a way or if you have any idea

Thanks all