Using Reporting Parameter for fun and profit

The new Pentaho Reporting 3.8 is the fourth release in a row where parameter played a important role. After ironing out all the easy problems, we are now in a state where we can think about creatively abusing the system.

There is one questions in the support centres that get repeated over and over again.

How do I limit the visible output types for a particular report?

Up until now, there was no sane answer. You either take it all, or you lock the report down to a single output type. But selecting just HTML and PDF, that was impossible.

The desired output for a report is controlled by the "output-target" parameter. The values for this parameter are defined somewhere deep inside the reporting engine. Every output target has its unique identifier, that tells both the type of the export (pageable or table) as well as the actual content type that is generated (text, html, pdf, and so on).

Output-target	Description
table/html;page-mode=stream	HTML as a single page, all report pagebreaks are ignored
table/html;page-mode=page	HTML as a sequence of physical pages, manual and automatic pagebreaks are active
application/vnd.openxmlformats-officedocument.spreadsheetml.sheet;page-mode=flow	Excel 2007 XLSX Workbook
table/excel;page-mode=flow	Excel 97 Workbook
table/csv;page-mode=stream	CSV output
table/rtf;page-mode=flow	Rich-Text-Format
pageable/pdf	PDF output
pageable/text	Plain text
pageable/xml	Pageable layouted XML
table/xml	Table-XML output
pageable/X-AWT-Graphics;image-type=png	A single report page as PNG
mime-message/text/html	Mime-Email with HTML as body text and all style and images as inline attachments

Since Pentaho Reporting 3.8, we check whether the current report defines one of the known system parameter. If you define your own representation of such a parameter, we use your definition instead of the built-in ones.

Using that knowledge, it is easy to create a list parameter that defines a subset of the available output types. Drop your selection into a table-datasource, and define the parameter as one of the single-selection list-parameter types.

Server Side Printing

You can also invoke server side printing directly from the parameter UI without having to go through an XAction. Define a boolean parameter by creating a table with the following entries:

ID	Value
false	Do Not Print
true	Print

Make sure you set the default value of your parameter to "false" or make false the first selection in your list, or you are likely to trigger printing involuntarily. Save the trees and so on.

If you want to print to a specific printer, you can do so by defining the "printer-name" parameter as well. And with the magic of the scriptable datasource, you can populate it with all known printers:

import javax.print.DocFlavor;
import javax.print.PrintService;
import javax.print.PrintServiceLookup;
import javax.print.attribute.standard.PrinterName;

import org.pentaho.reporting.engine.classic.core.modules.misc.tablemodel.TableModelInfo;
import org.pentaho.reporting.engine.classic.core.util.TypedTableModel; 


    PrintService[] services = PrintServiceLookup.lookupPrintServices(
        DocFlavor.SERVICE_FORMATTED.PAGEABLE, null);
    TypedTableModel tt = new TypedTableModel();
    tt.addColumn("ID", String.class);
    tt.addColumn("Value", String.class);
    for (int i = 0; i < services.length; i++)
    {
      PrintService service = services[i];
      PrinterName displayName = service.getAttribute(PrinterName.class);
      if (displayName != null)
      {
        tt.addRow(new Object[]{service.getName(), displayName.getValue()});
      }
      else
      {
        tt.addRow(new Object[]{service.getName(), service.getName()});
      }
    }
    return tt;