using conditions to print values in ireport - jasper-reports

Question

I am trying to use conditions to print value in table
I have three columns A B C
A is string
B is integer
C is integer
my condition is If column A == "user"
then print value in column B or make it null
($F{A}.equals("USER")?null:$F{B})
this gives type casting error
<jr:column width="15" uuid="733459e9-1ed8-4ce2-a74d-87dc078b1382">
<jr:tableFooter height="29" rowSpan="1"/>
<jr:columnFooter style="table 8_CH" height="30" rowSpan="1"/>
<jr:detailCell style="table 8_TD" height="20" rowSpan="1">
<textField isBlankWhenNull="true">
<reportElement x="0" y="0" width="15" height="20" uuid="bd3860a4-999a-4121-a701-3481a4fdf98e"/>
<textElement textAlignment="Center" verticalAlignment="Middle">
<font size="8"/>
</textElement>
<textFieldExpression><![CDATA[$F{TOP}]]></textFieldExpression>
</textField>
</jr:detailCell>
</jr:column>
<jr:column width="15" uuid="2e7fa82c-7f28-4af6-a63d-ae468afeea32">
<jr:tableFooter height="29" rowSpan="1"/>
<jr:columnFooter style="table 8_CH" height="30" rowSpan="1"/>
<jr:detailCell style="table 8_TD" height="20" rowSpan="1">
<textField isBlankWhenNull="true">
<reportElement x="0" y="0" width="15" height="20" uuid="33707346-9121-4010-8c12-981eb9f4de77">
<printWhenExpression><![CDATA[$F{TOP}.endsWith("NN")?null:$F{COP}]]></printWhenExpression>
</reportElement>
<textElement textAlignment="Center" verticalAlignment="Middle">
<font size="8"/>
</textElement>
<textFieldExpression><![CDATA[$F{COP}]]></textFieldExpression>
</textField>
</jr:detailCell>
</jr:column>

Answer 1

$F{TOP}.endsWith("NN")?null:$F{COP} this should not be in the "Print When Expression" field, for this is a boolean expression field: like print when expression if this = that. Like for instance if I never want to see that field I would put 0==1 in the print when expression field. So remove that line from the print when expression field.
You want to put the line in the field itself. So right-click the field TOP (I am assuming this is the field you want to change if it ends with NN) and select Edit Expression and put this line in replacement of $F{TOP}