[How do I stop report output if no data is returned?]

I have been looking at the answers for the past two+ hours and I see some ideas but no sample code.  I'm very new to Jasper Reports so as much detail you can provide the better.

I have an autometed scheduler running everyday at 8am to run a report.  Most days the query returns zero rows so I do not want the report to be created/emailed.

I tried adding the whenNoDataType="NoPages" but that did not work. (see example below)

In reading through the questions and answers it seems I must also add something like this...

JasperPrint _prnt = JasperManager.fillReport( _rep, params, conn); 

//check for pages here.--no pages helps here. 
if(_prnt.getPages().size()==0){ 
//redirect to std page 

jasperPrint.getPages().isEmpty()

But this is pretty foreign to me.  Can you provide me an example of where in the jrxml I would put the above text?  

 

I appreciate the help

 

EXAMPLE:

<?xml version="1.0" encoding="UTF-8"?>
<jasperReport 
    xmlns="http://jasperreports.sourceforge.net/jasperreports" 
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
    xsi:schemaLocation="http://jasperreports.sourceforge.net/jasperreports http://jasperreports.sourceforge.net/xsd/jasperreport.xsd" 
    name="POLA-Wharfage-Container" 
    language="groovy" 
    whenNoDataType="NoPages"
    pageWidth="595" pageHeight="842" columnWidth="555" leftMargin="20" rightMargin="20" topMargin="20" bottomMargin="20" 
    uuid="e0269380-8eae-4dcf-b533-73344ccbfcd3">
    <property name="ireport.zoom" value="1.0"/>
    <property name="ireport.x" value="0"/>
    <property name="ireport.y" value="0"/>
    <queryString>