Parallel fill with Java ParallelStream?

[Neobye]

We try to fill the reports in a parallel mode to speed up the fill process.
JasperReports allows to fill a a report with a list of objects (JRBeanCollectionDataSource), but the filling is done serial, even when you use JRThreadSubreportRunnerFactory.

Therefore we try to use Java parallelStream.

The trial setup is the following:

public class MyReportManager{    JasperReport jasperReport;    LocalJasperReportsContext context;        public MyReportManager(InputStream theInputStream){        // single instance of JasperReport //        jasperReport = (JasperReport) JRLoader.loadObject(theInputStream);                // single instance of context //        context = new LocalJasperReportsContext(DefaultJasperReportsContext.getInstance());        context.setClassLoader(getClass().getClassLoader());    }        public parallelFill(List<MyReportData> myReportData){        // parallel fill process        myReportData.parallelStream().forEach(data-> {            JasperFillManager fillManager = JasperFillManager.getInstance(context);            JasperPrint jasperPrint = fillManager.fill(report, data.getParams(), data.getDataSource());            data.setJasperPrint(jasperPrint);        });    }    ...    }[/code]

 

public class MyReportData{    Map<String, Object> params;    JRDataSource dataSource;    JasperPrint jasperPrint;        public MyReportData(Map<String, Object> theParams, JRDataSource theDataSource){        params = theParams;        dataSource = theDataSource;    }        public Map<String, Object> getParams(){        return params;    }        public JRDataSource getDataSource(){        return dataSource;    }        public JasperPrint getJasperPrint(){        return jasperPrint;    }        public void setJasperPrint(JasperPrint theJasperPrint){        jasperPrint = theJasperPrint;    }}[/code]

 

When we call the parallelFill with about 15000 ReportData, the process is working...most of the time, but not always.
Sometimes we suddenly encounter an JRException:

net.sf.jasperreport.engine.JRException: Byte data not found at: myStyle.jrtxat net.sf.jasperreports.repo.RepositoryUtil.getBytesFromLocation(ReporitoryUtil.java:210)at net.sf.jasperreports.engine.xml.JRXmlTemplateLoader.loadTemplate(JRXmlTemplateLoader.java:114)at net.sf.jasperreports.enginge.fill.JRFillReportTemplate.loadTemplate(JRFillReportTemplate.java:110)...[/code]

It looks like it tries to load the style in every fill process.

My Questions:

• is it possible to use parallel stream in conjunction with JasperFillManager? How do we achieve this?
• do I have to use a separate context for every fill process?
• why is the JasperStyleTemplate not loaded once in the JasperReport during it's load through JRLoader?

 

regards