How to show time (HH:mm) in bar chart value expression?

Question

I have designed a bar chart with String value in categorie CRANE_NUMBER and value expression REMAINING_TIME is java.util.Date.

When I run the report, I got error below.

Grave:   java.lang.ClassCastException: java.util.Date cannot be cast to java.lang.Number
    at net.sf.jasperreports.charts.fill.JRFillCategorySeries.evaluate(JRFillCategorySeries.java:141)
    at net.sf.jasperreports.charts.fill.JRFillCategoryDataset.customEvaluate(JRFillCategoryDataset.java:110)
    at net.sf.jasperreports.engine.fill.JRFillElementDataset.evaluate(JRFillElementDataset.java:172)
    at net.sf.jasperreports.engine.fill.JRCalculator.calculateVariables(JRCalculator.java:187)
    at net.sf.jasperreports.engine.fill.JRVerticalFiller.fillDetail(JRVerticalFiller.java:735)
    at net.sf.jasperreports.engine.fill.JRVerticalFiller.fillReportStart(JRVerticalFiller.java:255)
    at net.sf.jasperreports.engine.fill.JRVerticalFiller.fillReport(JRVerticalFiller.java:115)
    at net.sf.jasperreports.engine.fill.JRBaseFiller.fill(JRBaseFiller.java:582)
    at net.sf.jasperreports.engine.fill.BaseReportFiller.fill(BaseReportFiller.java:414)
    at net.sf.jasperreports.engine.fill.JRFiller.fill(JRFiller.java:121)
    at net.sf.jasperreports.engine.JasperFillManager.fill(JasperFillManager.java:667)
    at net.sf.jasperreports.engine.JasperFillManager.fill(JasperFillManager.java:648)
    at net.sf.jasperreports.engine.JasperFillManager.fillReport(JasperFillManager.java:970)

Is it possibile to show remaining time HH:mm in a barchart on the y-axis?

Answer 1

To create a bar chart with HH:mm on range axis, I would use a JRChartCustomizer

I will show a full example of how this can be achieved using the chart customizer, the library to renderer charts used by jasper-reports is jfreechart.

The JRChartCustomizer

public class ChartHHmmCustomizer implements JRChartCustomizer {

    @Override
    public void customize(JFreeChart jfchart, JRChart jrchart) {

        //Get the category plot
        CategoryPlot plot = (CategoryPlot) jfchart.getPlot();

        //Crete a date axis
        DateAxis yAxis = new DateAxis();
        //Override the date format
        yAxis.setDateFormatOverride(new SimpleDateFormat("HH:mm"));
        //Customize tick unit
        yAxis.setTickUnit(new DateTickUnit(DateTickUnitType.HOUR, 1));
        //Set it to the range axis
        plot.setRangeAxis(yAxis);

        //adding a customize item label renderer to view the valus on the barchart
        CategoryItemRenderer renderer = ((CategoryPlot) jfchart.getPlot()).getRenderer();
        renderer.setBaseItemLabelGenerator(new StandardCategoryItemLabelGenerator("{2}",new SimpleDateFormat("HH:mm")));
        renderer.setBaseItemLabelsVisible(true);
        ItemLabelPosition position = new ItemLabelPosition(ItemLabelAnchor.OUTSIDE12, TextAnchor.TOP_CENTER);
        renderer.setBasePositiveItemLabelPosition(position);
    }
}

The jrxml

<?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="timeBarChart" pageWidth="595" pageHeight="842" columnWidth="555" leftMargin="20" rightMargin="20" topMargin="20" bottomMargin="20" uuid="f71aa6b8-70ce-4de9-9e62-f8bd196e40f8">
    <queryString>
        <![CDATA[]]>
    </queryString>
    <field name="CraneNumber" class="java.lang.String"/>
    <field name="RemaningTime" class="java.util.Date"/>
    <columnHeader>
        <band height="20">
            <staticText>
                <reportElement x="0" y="0" width="100" height="20" uuid="af39006a-cd21-46c1-b74f-69fd3c570031"/>
                <textElement verticalAlignment="Middle">
                    <font isBold="true"/>
                </textElement>
                <text><![CDATA[CraneNumber]]></text>
            </staticText>
            <staticText>
                <reportElement x="100" y="0" width="100" height="20" uuid="83918a9e-3cd4-4581-8304-35246f8db5a9"/>
                <textElement verticalAlignment="Middle">
                    <font isBold="true"/>
                </textElement>
                <text><![CDATA[RemaningTime]]></text>
            </staticText>
        </band>
    </columnHeader>
    <detail>
        <band height="20" splitType="Stretch">
            <textField pattern="HH:mm">
                <reportElement x="100" y="0" width="100" height="20" uuid="a699d0ea-03fa-4232-8bc3-7b6c72c8e13c"/>
                <textElement verticalAlignment="Middle"/>
                <textFieldExpression><![CDATA[$F{RemaningTime}]]></textFieldExpression>
            </textField>
            <textField>
                <reportElement x="0" y="0" width="100" height="20" uuid="bbb040e5-4958-435a-90eb-b52f231ed5cd"/>
                <textElement verticalAlignment="Middle"/>
                <textFieldExpression><![CDATA[$F{CraneNumber}]]></textFieldExpression>
            </textField>
        </band>
    </detail>
    <summary>
        <band height="185" splitType="Stretch">
            <barChart>
                <chart isShowLegend="false" customizerClass="my.package.ChartHHmmCustomizer">
                    <reportElement x="66" y="29" width="356" height="141" uuid="60bdb0d1-8c39-4fdc-98b9-d1c5458cb665"/>
                    <chartTitle/>
                    <chartSubtitle/>
                    <chartLegend/>
                </chart>
                <categoryDataset>
                    <categorySeries>
                        <seriesExpression><![CDATA["My cranes"]]></seriesExpression>
                        <categoryExpression><![CDATA[$F{CraneNumber}]]></categoryExpression>
                        <valueExpression><![CDATA[$F{RemaningTime}.getTime()]]></valueExpression>
                    </categorySeries>
                </categoryDataset>
                <barPlot>
                    <plot/>
                    <itemLabel/>
                    <categoryAxisFormat>
                        <axisFormat/>
                    </categoryAxisFormat>
                    <valueAxisLabelExpression/>
                    <valueAxisFormat>
                        <axisFormat/>
                    </valueAxisFormat>
                </barPlot>
            </barChart>
        </band>
    </summary>
</jasperReport>

Note: That I add the customizerClass="my.package.ChartHHmmCustomizer"to chart component and as valueExpression I set $F{RemaningTime}.getTime(), hence the time in milliseconds (a number)

Some data

+-------------+--------------+
| CraneNumber | RemaningTime |
+-------------+--------------+
| Crane1      | 04:20        |
| Crane2      | 02:13        |
| Crane3      | 06:31        |
+-------------+--------------+

Output