PrimeFaces Export data from a Lazyloading DataTable - jsf-2

Question

I want to export a dataTable (with Pagination) having LazyLoad DataModel during Report Generation.
Problem :
When I export, the report is getting generated page by page from Database and then getting exported to Excel/PDF that consumes more time. I would like to get it in a single database access by skipping the page by page generation of dataset.
I'm producing my code snippet as follows:
JSF:
<p:dataTable id="dTable" var="dev" value="#{ReportAction.lazyModel}"
styleClass ="table_paginator" rowKey="#{device.macAddress}" paginatorPosition="bottom"
paginator="true" rowsPerPageTemplate="10,20,30" rows="10" lazy="true"
paginatorTemplate="{CurrentPageReport} {FirstPageLink} {PreviousPageLink} {PageLinks} {NextPageLink} {LastPageLink} {RowsPerPageDropdown}"
emptyMessage="Select appropriate conditions and click 'Generate Report'">
<f:facet name="header">
<h:commandLink actionListener="#{ReportAction.doExport}">
<p:graphicImage value="../../../resources/images/excel.png"
alt="XLS" style="float:right;width:32px;height:32px" />
<p:dataExporter type="xls" target="dTable" fileName="#{ReportAction.fileName}"
preProcessor="#{ReportAction.preProcess}"
postProcessor="#{ReportAction.postProcessXLS}" />
</h:commandLink>
</f:facet>
<!-- All the columns in Data Table -->
</p:dataTable>
Managed Bean:
public class ReportAction {
private ConfigurationReportDataModel mediumConfigModel;
private List<FieldReportModel> configModelList;
private String fileName;
private LazyDataModel<ConfigurationReportModel> lazyModel;
private boolean export;
public ReportAction() {
configModelList = new ArrayList<ConfigurationReportModel>();
export = false;
mediumConfigModel = new ReportDataModel();
}
public void generateFieldReport() {
lazyFieldModel = new ConfigurationReportDataModel(day, fromDate,
location,store,engineer, status, toDate, export);
}
public void preProcess(Object document) {
export = true;
log.info("preProcess::Lazy model : Page Sizing");
if(lazyFieldModel != null) {
lazyFieldModel.setPageSize(1000000);
}
log.info("preProcess::Export All Details");
mediumConfigModel.setExport(true);
}
public void postProcessXLS(Object document) {
HSSFWorkbook wb = (HSSFWorkbook) document;
HSSFSheet sheet = wb.getSheetAt(0);
HSSFRow header = sheet.getRow(0);
HSSFCellStyle cellStyle = wb.createCellStyle();
cellStyle.setFillForegroundColor(HSSFColor.GREEN.index);
cellStyle.setFillPattern(HSSFCellStyle.SOLID_FOREGROUND);
for (int i = 0; i < header.getPhysicalNumberOfCells(); i++) {
HSSFCell cell = header.getCell(i);
cell.setCellValue(cell.getStringCellValue().toUpperCase());
cell.setCellStyle(cellStyle);
sheet.autoSizeColumn(i);
}
export = false;
mediumConfigModel.setExport(false);
}
public List<ConfigurationReportModel> getConfigModelList() {
return configModelList;
}
public void setConfigModelList(
ArrayList<ConfigurationReportModel> configModelList) {
this.configModelList = configModelList;
}
public String getFileName() {
SimpleDateFormat formatter = new SimpleDateFormat("ddMMyyyy_HHmmss");
fileName = "Config_Report_".concat(formatter.format(new Date()));
return fileName;
}
public void setMediumConfigModel(
ConfigurationReportDataModel mediumConfigModel) {
this.mediumConfigModel = mediumConfigModel;
}
public void setConfigModelList(
List<ConfigurationReportModel> configModelList) {
this.configModelList = configModelList;
}
public LazyDataModel<ConfigurationReportModel> getLazyFieldModel() {
log.info("##########getLazyFieldModel###########");
if(export) {
log.info("getLazyFieldModel::Will get Exported........");
lazyFieldModel = new ConfigurationReportDataModel(day, fromDate,
location, store, engineer, status, toDate, true);
lazyFieldModel.load(1, 1000000000, null, null, null);
}
return lazyFieldModel;
}
public void setLazyFieldModel(
LazyDataModel<ConfigurationReportModel> lazyFieldModel) {
this.lazyFieldModel = lazyFieldModel;
}
}
DataModel:
public class ConfigurationReportDataModel extends
LazyDataModel<ConfigurationReportModel> {
private List<ConfigurationReportModel> configReport;
private boolean export;
public ConfigurationReportDataModel() {
this.export = false;
}
public List<ConfigurationReportModel> load(int first, int pageSize,
String sortField, SortOrder sortOrder, Map<String, String> filters) {
UIClient client = new UIClient();
ReportData data = null;
// ///////////////////
if(export) {
log.info("Do Export....");
first = 1;
pageSize = 1000000000;
}
deviceList = new ArrayList<DeviceGlobal>();
// Retrieves data from Database with the number of record (page size)
data = client.generateFieldReport(first, pageSize,
Integer.parseInt(location), Integer.parseInt(store),
engineer, getTimeToBeginningOfDay(), getTimeToEndofDay(),
status);
log.info("Obtained data : " + data);
if (data != null) {
log.info("Got devices : " + data.getRecords().size());
deviceList = (ArrayList<DeviceGlobal>) data.getRecords();
// ///////////////////
int record = first + 1;
ConfigurationReportModel storeModel = null;
DeviceGlobal deviceGlobal = null;
configReport = new ArrayList<ConfigurationReportModel>();
for (Iterator<DeviceGlobal> iterator = deviceList.iterator(); iterator
.hasNext();) {
deviceGlobal = (DeviceGlobal) iterator.next();
storeModel = new ConfigurationReportModel(deviceGlobal,
record++);
configReport.add(storeModel);
}
log.info("Total Config Report : " + configReport.size());
// rowCount
int dataSize = data.getReportCount();
this.setRowCount(dataSize);
log.info("Report Count: " + data.getReportCount());
if(export) {
return configReport;
}
else {
// paginate
if (dataSize > pageSize) {
try {
return configReport;
} catch (IndexOutOfBoundsException e) {
return configReport;
}
} else {
return configReport;
}
}
} else {
log.info("Got no devices");
deviceList = new ArrayList<DeviceGlobal>();
configReport = new ArrayList<ConfigurationReportModel>();
this.setRowCount(0);
return configReport;
}
}
}
Note:
There's no syntax error.
All the custom type classes are defined.
How do I get the Excel report by skipping the page by page generation of records?

Answer 1

You have to add pageOnly="false" to dataExporter

Answer 2

for zero devision issue just override an extra LaztDataModel method as given below.
#Override
public void setRowIndex(int rowIndex) {
// TODO Auto-generated method stub
if (rowIndex == -1 || getPageSize() == 0) {
super.setRowIndex(-1);
}
else
super.setRowIndex(rowIndex % getPageSize());
}