Group several same value field into a single cell

First of all, the records are shown in the table by table component but not in the report one.

The results looks like this:

 YEARS MONTHS SUMMONTH SUMQUARTER   
 ----- ------ -------- ----------  
  2009 Jan      130984     432041
       Feb      146503
       Mar      154554     
       Apr      147917     435150 
       May      131822     
       Jun      155411     
       Jul      144000     424806 
       Aug      130369     
       Sep      150437     
       Oct      112137     400114 
       Nov      152057     
       Dec      135920     
 =====================================
       Jan-Dec  1692111
 =====================================
  2010 Jan      139927     417564 
       Feb      154940     
       Mar      122697     
       Apr      163257     413305 
       May      124999     
       Jun      125049     
       Jul      145127     427612 
       Aug      138804     
       Sep      143681     
       Oct      143398     406381 
       Nov      125351     
       Dec      137632     
 =====================================
       Jan-Dec  1664862
 =====================================

The sumquarter column shows the sum of each quarter in year.

They are not printed when it repeated the value of the field.

The question is how to group the column of sumquarter, so that the first printed repeated value in each row to join the next repeated value to become a single cell until it meets the non-repeated value?

You can simply see it in an image. Below is the image that the table shows and the solution that I preferred is to group those 3 months of sum into a single cell.

Here is the image:


You can use this sample:

<?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="year_sum_quarter" language="groovy" pageWidth="595" pageHeight="842" columnWidth="555" leftMargin="20" rightMargin="20" topMargin="20" bottomMargin="20">
    <property name="ireport.zoom" value="1.0"/>
    <property name="ireport.x" value="0"/>
    <property name="ireport.y" value="0"/>
    <queryString>
        <![CDATA[]]>
    </queryString>
    <field name="year" class="java.lang.Integer"/>
    <field name="month" class="java.lang.String"/>
    <field name="sum" class="java.lang.Integer"/>
    <field name="q" class="java.lang.Integer"/>
    <variable name="yearSum" class="java.lang.Integer" resetType="Group" resetGroup="yearGroup" calculation="Sum">
        <variableExpression><![CDATA[$F{sum}]]></variableExpression>
    </variable>
    <variable name="qSum" class="java.lang.Integer" resetType="Group" resetGroup="quaterGroup" calculation="Sum">
        <variableExpression><![CDATA[$F{sum}]]></variableExpression>
    </variable>
    <group name="yearGroup">
        <groupExpression><![CDATA[$F{year}]]></groupExpression>
        <groupFooter>
            <band height="20">
                <textField>
                    <reportElement x="100" y="0" width="100" height="20"/>
                    <box leftPadding="10">
                        <topPen lineWidth="1.0"/>
                        <leftPen lineWidth="0.0"/>
                        <bottomPen lineWidth="1.0"/>
                        <rightPen lineWidth="0.0"/>
                    </box>
                    <textElement/>
                    <textFieldExpression><![CDATA["Jan-Dec, " + $F{year}]]></textFieldExpression>
                </textField>
                <textField>
                    <reportElement x="200" y="0" width="100" height="20"/>
                    <box leftPadding="0">
                        <topPen lineWidth="1.0"/>
                        <leftPen lineWidth="0.0"/>
                        <bottomPen lineWidth="1.0"/>
                        <rightPen lineWidth="0.0"/>
                    </box>
                    <textElement/>
                    <textFieldExpression><![CDATA[$V{yearSum}]]></textFieldExpression>
                </textField>
                <staticText>
                    <reportElement x="0" y="0" width="100" height="20"/>
                    <box>
                        <topPen lineWidth="1.0"/>
                        <leftPen lineWidth="1.0"/>
                        <bottomPen lineWidth="1.0"/>
                        <rightPen lineWidth="0.0"/>
                    </box>
                    <textElement textAlignment="Center" verticalAlignment="Middle">
                        <font isBold="true" isItalic="true"/>
                    </textElement>
                    <text><![CDATA[]]></text>
                </staticText>
                <staticText>
                    <reportElement x="300" y="0" width="100" height="20"/>
                    <box>
                        <topPen lineWidth="1.0"/>
                        <leftPen lineWidth="0.0"/>
                        <bottomPen lineWidth="1.0"/>
                        <rightPen lineWidth="1.0"/>
                    </box>
                    <textElement textAlignment="Center" verticalAlignment="Middle">
                        <font isBold="true" isItalic="true"/>
                    </textElement>
                    <text><![CDATA[]]></text>
                </staticText>
            </band>
        </groupFooter>
    </group>
    <group name="quaterGroup">
        <groupExpression><![CDATA[$F{year} + $F{q}]]></groupExpression>
    </group>
    <columnHeader>
        <band height="50">
            <staticText>
                <reportElement x="100" y="30" width="100" height="20"/>
                <box>
                    <topPen lineWidth="1.0"/>
                    <leftPen lineWidth="1.0"/>
                    <bottomPen lineWidth="1.0"/>
                    <rightPen lineWidth="1.0"/>
                </box>
                <textElement textAlignment="Center" verticalAlignment="Middle">
                    <font isBold="true" isItalic="true"/>
                </textElement>
                <text><![CDATA[Month]]></text>
            </staticText>
            <staticText>
                <reportElement x="0" y="30" width="100" height="20"/>
                <box>
                    <topPen lineWidth="1.0"/>
                    <leftPen lineWidth="1.0"/>
                    <bottomPen lineWidth="1.0"/>
                    <rightPen lineWidth="1.0"/>
                </box>
                <textElement textAlignment="Center" verticalAlignment="Middle">
                    <font isBold="true" isItalic="true"/>
                </textElement>
                <text><![CDATA[Year]]></text>
            </staticText>
            <staticText>
                <reportElement x="200" y="30" width="100" height="20"/>
                <box>
                    <topPen lineWidth="1.0"/>
                    <leftPen lineWidth="1.0"/>
                    <bottomPen lineWidth="1.0"/>
                    <rightPen lineWidth="1.0"/>
                </box>
                <textElement textAlignment="Center" verticalAlignment="Middle">
                    <font isBold="true" isItalic="true"/>
                </textElement>
                <text><![CDATA[Month Sum]]></text>
            </staticText>
            <staticText>
                <reportElement x="300" y="30" width="100" height="20"/>
                <box>
                    <topPen lineWidth="1.0"/>
                    <leftPen lineWidth="1.0"/>
                    <bottomPen lineWidth="1.0"/>
                    <rightPen lineWidth="1.0"/>
                </box>
                <textElement textAlignment="Center" verticalAlignment="Middle">
                    <font isBold="true" isItalic="true"/>
                </textElement>
                <text><![CDATA[Quarter Sum]]></text>
            </staticText>
        </band>
    </columnHeader>
    <detail>
        <band height="20" splitType="Stretch">
            <staticText>
                <reportElement x="300" y="0" width="100" height="20"/>
                <box>
                    <topPen lineWidth="0.0"/>
                    <leftPen lineWidth="1.0"/>
                    <bottomPen lineWidth="0.0"/>
                    <rightPen lineWidth="1.0"/>
                </box>
                <textElement textAlignment="Center" verticalAlignment="Middle">
                    <font isBold="true" isItalic="true"/>
                </textElement>
                <text><![CDATA[]]></text>
            </staticText>
            <staticText>
                <reportElement x="0" y="0" width="100" height="20"/>
                <box>
                    <topPen lineWidth="0.0"/>
                    <leftPen lineWidth="1.0"/>
                    <bottomPen lineWidth="0.0"/>
                    <rightPen lineWidth="1.0"/>
                </box>
                <textElement textAlignment="Center" verticalAlignment="Middle">
                    <font isBold="true" isItalic="true"/>
                </textElement>
                <text><![CDATA[]]></text>
            </staticText>
            <textField>
                <reportElement x="0" y="0" width="100" height="20">
                    <printWhenExpression><![CDATA[$V{yearGroup_COUNT} == 1]]></printWhenExpression>
                </reportElement>
                <box leftPadding="10">
                    <topPen lineWidth="0.0"/>
                    <leftPen lineWidth="1.0"/>
                    <bottomPen lineWidth="0.0"/>
                    <rightPen lineWidth="1.0"/>
                </box>
                <textElement/>
                <textFieldExpression><![CDATA[$F{year}]]></textFieldExpression>
            </textField>
            <textField>
                <reportElement x="200" y="0" width="100" height="20"/>
                <box leftPadding="10">
                    <topPen lineWidth="1.0"/>
                    <leftPen lineWidth="1.0"/>
                    <bottomPen lineWidth="1.0"/>
                    <rightPen lineWidth="1.0"/>
                </box>
                <textElement/>
                <textFieldExpression><![CDATA[$F{sum}]]></textFieldExpression>
            </textField>
            <textField>
                <reportElement x="100" y="0" width="100" height="20"/>
                <box leftPadding="10">
                    <topPen lineWidth="1.0"/>
                    <leftPen lineWidth="1.0"/>
                    <bottomPen lineWidth="1.0"/>
                    <rightPen lineWidth="1.0"/>
                </box>
                <textElement/>
                <textFieldExpression><![CDATA[$F{month}]]></textFieldExpression>
            </textField>
            <textField evaluationTime="Group" evaluationGroup="quaterGroup" isBlankWhenNull="false">
                <reportElement stretchType="RelativeToBandHeight" isPrintRepeatedValues="false" x="300" y="0" width="100" height="20" printWhenGroupChanges="quaterGroup">
                    <printWhenExpression><![CDATA[$V{quaterGroup_COUNT} == 1]]></printWhenExpression>
                </reportElement>
                <box leftPadding="10">
                    <topPen lineWidth="0.0"/>
                    <leftPen lineWidth="1.0"/>
                    <bottomPen lineWidth="0.0"/>
                    <rightPen lineWidth="1.0"/>
                </box>
                <textElement/>
                <textFieldExpression><![CDATA[$V{qSum}]]></textFieldExpression>
            </textField>
            <line>
                <reportElement x="300" y="0" width="100" height="1" printWhenGroupChanges="quaterGroup">
                    <printWhenExpression><![CDATA[$V{quaterGroup_COUNT} == 1]]></printWhenExpression>
                </reportElement>
            </line>
        </band>
    </detail>
</jasperReport>

The result will be (in pdf format): Resulting report in PDF format

In this sample I've used two elements in the Detail band for the Year column: one textField with only vertical borders and with printWhenExpression: "$V{yearGroup_COUNT} == 1" property (I'm show it only once for the whole yearGroup) and one staticText without any text and with only vertical borders.

I've used three elements in the Detail band for the Quarter Sum column:
one textField with only vertical borders and with printWhenExpression: "$V{quaterGroup_COUNT} == 1" property (I'm show it only once for the whole quaterGroup), one staticText without any text and with only vertical borders and the line element for drawing horizontal border with printWhenExpression: "$V{quaterGroup_COUNT} == 1" property.