Jaspersoft plugin for Eclipse: Can't compile Jasper report. "The method is undefined for the type Object"

I use Jaspersoft plugin in Eclipse. I have a field in .jrxml file that prints distinct Artists featured in an Album. I did it using Java Stream API. The type of that field is java.util.List. But I can't compile the file, because the method getArtists() is undefinted for the type of Object, yet the type of variable t is Track.

Console:

Started the compilation of the resource albumreport.jrxml
net.sf.jasperreports.engine.JRException: Errors were encountered when compiling report expressions class file:
1. The method getArtists() is undefined for the type Object
                value = ((java.util.List)field_tracks.getValue()).stream().flatMap(t -> t.getArtists().stream()).map(a -> a.getName()).distinct().reduce("", (n1, n2) -> n1 + ", " + n2); //$JR_EXPR_ID=11$
                                                                                          <-------->
2. The method getName() is undefined for the type Object
                value = ((java.util.List)field_tracks.getValue()).stream().flatMap(t -> t.getArtists().stream()).map(a -> a.getName()).distinct().reduce("", (n1, n2) -> n1 + ", " + n2); //$JR_EXPR_ID=11$
                                                                                                                            <----->
3. The method getArtists() is undefined for the type Object
                value = ((java.util.List)field_tracks.getOldValue()).stream().flatMap(t -> t.getArtists().stream()).map(a -> a.getName()).distinct().reduce("", (n1, n2) -> n1 + ", " + n2); //$JR_EXPR_ID=11$
                                                                                             <-------->
4. The method getName() is undefined for the type Object
                value = ((java.util.List)field_tracks.getOldValue()).stream().flatMap(t -> t.getArtists().stream()).map(a -> a.getName()).distinct().reduce("", (n1, n2) -> n1 + ", " + n2); //$JR_EXPR_ID=11$
                                                                                                                               <----->
5. The method getArtists() is undefined for the type Object
                value = ((java.util.List)field_tracks.getValue()).stream().flatMap(t -> t.getArtists().stream()).map(a -> a.getName()).distinct().reduce("", (n1, n2) -> n1 + ", " + n2); //$JR_EXPR_ID=11$
                                                                                          <-------->
6. The method getName() is undefined for the type Object
                value = ((java.util.List)field_tracks.getValue()).stream().flatMap(t -> t.getArtists().stream()).map(a -> a.getName()).distinct().reduce("", (n1, n2) -> n1 + ", " + n2); //$JR_EXPR_ID=11$
                                                                                                                            <----->
6 errors
.
    at net.sf.jasperreports.engine.design.JRAbstractCompiler.compileReport(JRAbstractCompiler.java:229)
    at net.sf.jasperreports.eclipse.builder.JasperReportCompiler.compileReport(JasperReportCompiler.java:289)
    at net.sf.jasperreports.eclipse.builder.JasperReportCompiler.compileReport(JasperReportCompiler.java:141)
    at net.sf.jasperreports.eclipse.builder.JasperReportsBuilder.compileJRXML(JasperReportsBuilder.java:212)
    at com.jaspersoft.studio.editor.action.CompileAction.actionCompile(CompileAction.java:159)
    at com.jaspersoft.studio.editor.action.CompileAction$1.run(CompileAction.java:101)
    at org.eclipse.core.internal.jobs.Worker.run(Worker.java:63)
 
 
Unable to create the binary file, check the compilation errors

Album.java:

@Entity
@Table(name="album")
@NamedQuery(name="Album.findAll", query="SELECT a FROM Album a")
public class Album implements Serializable {
    private static final long serialVersionUID = 1L;
    // ...
    //bi-directional many-to-one association to Track
    @OneToMany(mappedBy="album")
    private List<Track> tracks;
    // ...
    public List<Track> getTracks() {
        return this.tracks;
    }
}

Track.java:

@Entity
@Table(name="track")
@NamedQuery(name="Track.findAll", query="SELECT t FROM Track t")
public class Track implements Serializable {
    private static final long serialVersionUID = 1L;
    // ...
    //bi-directional many-to-many association to Artist
    @ManyToMany
    @JoinTable(
        name="producestracks"
        , joinColumns={
            @JoinColumn(name="trackid")
            }
        , inverseJoinColumns={
            @JoinColumn(name="artistid")
            }
        )
    private List<Artist> artists;
    // ...
    public List<Artist> getArtists() {
        return this.artists;
    }
 
    public void setArtists(List<Artist> artists) {
        this.artists = artists;
    }
}

AlbumController.java

@RequestMapping(value = "/createJasperReport", method = RequestMethod.GET)
public void createJasperReport(HttpServletResponse response) throws Exception {
    response.setContentType("text/html");
    JRBeanCollectionDataSource dataSource = new JRBeanCollectionDataSource(alr.findAll());
    InputStream inputStream = this.getClass().getResourceAsStream("/jasperreports/albumreport.jrxml");
    JasperReport jasperReport = JasperCompileManager.compileReport(inputStream);
    JasperPrint jasperPrint = JasperFillManager.fillReport(jasperReport, null, dataSource);
    inputStream.close();
    response.setContentType("application/x-download");
    response.addHeader("Content-disposition", "attachment; filename=albumreport.pdf");
    OutputStream outputStream = response.getOutputStream();
    JasperExportManager.exportReportToPdfStream(jasperPrint, outputStream);
}
IgorArnaut's picture
Joined: Jan 26 2022 - 3:41am
Last seen: 3 months 1 week ago

I tried to solve it by casting, but now Track cannot be resolved to a type.

IgorArnaut - 3 months 3 weeks ago

For some reason, Jaspersoft plugin doesn't recognize lambda operators as valid.

IgorArnaut - 3 months 3 weeks ago

It's been a week and nobody did reply.

IgorArnaut - 3 months 2 weeks ago

1 Answer:

The type of the field is java.util.List, but the compiler cannot know that it's a list of Track objects.

What you can do is to cast $F{tracks} to List<Track> (note the you'll have to fully qualify the Track class name), which should allow the compiler to infer Track as the type of the t variable.

Regards,

Lucian

lucianc's picture
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Joined: Jul 17 2006 - 1:10am
Last seen: 2 weeks 5 days ago
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