JRBeanCollectionDataSource: How to show data from the java.util.List from JavaBean?

Question:

In a JavaBean, there's a data member that's a java.util.List. How do you display the data in that List in the Detail band of a report?

Answer:

Here's how to do it:

Working sample

Key points:

• Uses the _THIS expression
• Uses the List (jr:list) component in the Detail band

Code to generate report:

public static void testBuildPdf() {
    try {
        Map<string object> params = new HashMap();
        JasperReport jasperReport = JasperCompileManager.compileReport(reportSource);
        JasperPrint jasperPrint = JasperFillManager.fillReport(jasperReport, params, getDataSource());

        JasperExportManager.exportReportToPdfFile(jasperPrint, outputFileName);
    } catch (Exception e) {
        e.printStackTrace();
    }
}

private static JRDataSource getDataSource() {
    Collection<beanwithlist> coll = new ArrayList();
    coll.add(new BeanWithList(Arrays.asList("London", "Paris"), 1));
    coll.add(new BeanWithList(Arrays.asList("London", "Madrid", "Moscow"), 2));
    coll.add(new BeanWithList(Arrays.asList("Rome"), 3));

    return new JRBeanCollectionDataSource(coll);
}</beanwithlist></string>

JavaBean code:

public class BeanWithList {

    // The member's name can be any. The JR engine is using public getter for extracting field's value
    private List<string> cities;
    private Integer id;

    public BeanWithList(List<string> cities, Integer id) {
        this.cities = cities;
        this.id = id;
    }

    // getter should be public    
    public List<string> getCities() {
        return this.cities;
    }

    public Integer getId() {
        return this.id;
    }
}</string></string></string>

JRXML file:

<?xml version="1.0" encoding="UTF-8"?>
<jasperreport ...>
    <subdataset name="dataset1">
        <field name="city" class="java.lang.String">
            <fielddescription></fielddescription>
        </field>
    </subdataset>
    <field name="id" class="java.lang.Integer"></field>
    <field name="cities" class="java.util.Collection"></field>
    <title>
        <band height="103" splittype="Stretch">
            <statictext>
                <reportelement x="138" y="28" width="258" height="20"></reportelement>
                <textelement textalignment="Center" verticalalignment="Middle">
                    <font isbold="true" isitalic="true"></font>
                </textelement>
                <text></text>
            </statictext>
        </band>
    </title>
    <columnheader>
        <band height="20">
            <statictext>
                <reportelement x="0" y="0" width="100" height="20"></reportelement>
                <box>
                    <toppen linewidth="1.0"></toppen>
                    <leftpen linewidth="1.0"></leftpen>
                    <bottompen linewidth="1.0"></bottompen>
                    <rightpen linewidth="1.0"></rightpen>
                </box>
                <textelement textalignment="Center" verticalalignment="Middle">
                    <font isbold="true" isitalic="true" isunderline="false"></font>
                </textelement>
                <text></text>
            </statictext>
            <statictext>
                <reportelement x="100" y="0" width="100" height="20"></reportelement>
                <box>
                    <toppen linewidth="1.0"></toppen>
                    <leftpen linewidth="1.0"></leftpen>
                    <bottompen linewidth="1.0"></bottompen>
                    <rightpen linewidth="1.0"></rightpen>
                </box>
                <textelement textalignment="Center" verticalalignment="Middle">
                    <font isbold="true" isitalic="true" isunderline="false"></font>
                </textelement>
                <text></text>
            </statictext>
        </band>
    </columnheader>
    <detail>
        <band height="20" splittype="Stretch">
            <textfield>
                <reportelement stretchtype="RelativeToTallestObject" x="0" y="0" width="100" height="20"></reportelement>
                <box leftpadding="10">
                    <toppen linewidth="1.0"></toppen>
                    <leftpen linewidth="1.0"></leftpen>
                    <bottompen linewidth="1.0"></bottompen>
                    <rightpen linewidth="1.0"></rightpen>
                </box>
                <textelement></textelement>
                <textfieldexpression></textfieldexpression>
            </textfield>
            <componentelement>
                <reportelement x="100" y="0" width="400" height="20"></reportelement>
                <list xmlns:jr="http://jasperreports.sourceforge.net/jasperreports/components" xsi:schemalocation="http://jasperreports.sourceforge.net/jasperreports/components http://jasperreports.sourceforge.net/xsd/components.xsd" printorder="Vertical">
                    <datasetrun subdataset="dataset1">
                        <datasourceexpression></datasourceexpression>
                    </datasetrun>
                    <listcontents height="20" width="400">
                        <textfield>
                            <reportelement x="0" y="0" width="100" height="20"></reportelement>
                            <box leftpadding="10">
                                <toppen linewidth="1.0"></toppen>
                                <leftpen linewidth="1.0"></leftpen>
                                <bottompen linewidth="1.0"></bottompen>
                                <rightpen linewidth="1.0"></rightpen>
                            </box>
                            <textelement></textelement>
                            <textfieldexpression></textfieldexpression>
                        </textfield>
                    </listcontents>
                </list>
            </componentelement>
        </band>
    </detail>
</jasperreport>

Result:

Related questions:

• How do I print a list of strings contained within another list in iReport?
• Passing the List of primitive type objects as datasource for subreport

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