How to create a line chart with date's on both axis?

Question

I need to implement a two date type axis with jasper-reports.

The time series chart allows a date on x-axis and a number value on y-axis, is there a way to implements two date type axis where both y-axis and x-axis is of date type?

Answer 1

To set y-axis as a Date axis you need to.

1. Convert the Date in the valueExpression to a java.lang.Number, since valueExpression does only allow this class (or a sub class)

Instead of passing a java.util.Date in the valueExpression pass the time in milliseconds java.lang.Long by calling Date.getTime()

<valueExpression><![CDATA[$F{myDateOnYAxis}.getTime()]]></valueExpression>

2. Add a JRChartCustomizer that changes the number axis to a date axis with relative formatter

public class MyChartCustomizer implements JRChartCustomizer {

    @Override
    public void customize(JFreeChart jfchart, JRChart jrchart) {
        XYPlot plot = (XYPlot) jfchart.getPlot(); //get the plot

        //Create the new date axis for y
        DateAxis yDateAxis = new DateAxis();
        //Set desired time format
        DateFormat dateFormat = new SimpleDateFormat("MMM - yyyy"); 
        yDateAxis.setDateFormatOverride(dateFormat); 
        //Add your own Tickunit if you like (you can do with out also, comment out the below line and let JFreeChart decided)
        yDateAxis.setTickUnit(new DateTickUnit(DateTickUnitType.MONTH,3));

        //Set the new y-axis to the plot
        plot.setRangeAxis(yDateAxis);
    }
}

For how to add JRChartCustomizer to your design (jrxml) see Sample reference

Result

^{*Some random dates formatted in Italian}

Example jrxml used to generate graph with a csv datasource

<?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="Test2DateGraph" pageWidth="595" pageHeight="842" columnWidth="555" leftMargin="20" rightMargin="20" topMargin="20" bottomMargin="20" uuid="2347c131-1884-430a-b77f-59f08f896c8a">
	<property name="com.jaspersoft.studio.data.defaultdataadapter" value="Dates"/>
	<queryString language="csv">
		<![CDATA[]]>
	</queryString>
	<field name="Date1" class="java.util.Date"/>
	<field name="Date2" class="java.util.Date"/>
	<summary>
		<band height="353">
			<timeSeriesChart>
				<chart evaluationTime="Report" customizerClass="MyChartCustomizer">
					<reportElement x="10" y="50" width="530" height="256" uuid="4a93e72e-251b-4026-bb11-edc26ecd6599"/>
					<chartTitle/>
					<chartSubtitle/>
					<chartLegend/>
				</chart>
				<timeSeriesDataset>
					<timeSeries>
						<seriesExpression><![CDATA["SERIES 1"]]></seriesExpression>
						<timePeriodExpression><![CDATA[$F{Date2}]]></timePeriodExpression>
						<valueExpression><![CDATA[$F{Date2}.getTime()]]></valueExpression>
					</timeSeries>
				</timeSeriesDataset>
				<timeSeriesPlot>
					<plot/>
					<timeAxisFormat>
						<axisFormat/>
					</timeAxisFormat>
					<valueAxisFormat>
						<axisFormat/>
					</valueAxisFormat>
				</timeSeriesPlot>
			</timeSeriesChart>
		</band>
	</summary>
</jasperReport>

Note: If your not using a timeSeriesChart, the same needs to be done with x-axis.