How to use printWhenExpression in JasperReports

Question

Can somebody tell me how to use the printWhenExpression of JasperReports?

Answer 1

Do you have an error relative to boolean ?

Because you need to use Boolean instead of the primitive type.

So:

$F{mesure} != "PH"
($F{userfd4}).equals("1") ? true : false 

would give cannot cast from boolean to Boolean.

( $F{mesure}.startsWith("PH") ? Boolean.TRUE:Boolean.FALSE ) 
($F{userfd4}).equals("1") ? Boolean.TRUE : Boolean.FALSE  

would be correct.

See also this example

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Update Nov 2015 (7 years later)

Petter Friberg points out in the comments:

In jasper report 6.0 this is not need:
You can return either boolean or Boolean a simple expression like $F{fieldName}.equals("hello") will work.

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You can see a demo of that command in demo/samples/tableofcontents/reports/TocPart.jrxml

<reportElement style="Sans_Bold" positionType="Float" x="50" y="0" width="100" height="15" isRemoveLineWhenBlank="true" uuid="db8b68c6-4430-4199-8967-3ab5c077cb56">
    <property name="local_mesure_unitx" value="pixel"/>
    <property name="com.jaspersoft.studio.unit.x" value="px"/>
    <printWhenExpression><![CDATA[$F{level} == 1]]></printWhenExpression>
</reportElement>