Monthly Archives: March 2011

An easy way of Printing Aggregations

Setting up a large number of aggregated values like sums, counts or averages can be a dreadful experience in the Pentaho Report Designer.

Calculations are performed by functions and expressions (let me call it just functions). These functions are added in the data tab of the report designer. Each function gets a name under which its result can be referenced. And then it needs to be configured properly. Usually, you have to set at least the field it should work on and the group on which it should reset.

Doing it for one field is not exciting, but ok. Doing it for 10 fields is no longer fun.

If you just want to print the result of that calculation, without ever using it as part of another computation, then here’s an easier way of aggregating data:

(1) Drag a number field onto your report and assign a field name to it (attribute common::fieldname).
(2) Set the aggregation you want to use via the attribute “wizard::aggregation-type”.
(3) Optional: Define the group on which you want to reset. If not defined, the current group is used.

This way of defining aggregations is used by the Report Design Wizard. To see a working example – just generate a report with it and add a summary on the fields.

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()});
        tt.addRow(new Object[]{service.getName(), service.getName()});
    return tt;

Pentaho Reporting 3.8.0 is here … says the official annoucement.

The long waiting is over. Today Pentaho announced the release of Pentaho Reporting 3.8.0 and the BI-Server 3.8.0.

This release is mainly a bug-fix release with only few new features. Over the last few months we concentrated on making this release a “god damn stable” beast. With 132 cases solved and numerous blocker-class fixes resolved, I think we reached that goal.

On the new-feature side, we still have some good things to report:

  • Report data can and will be cached now. This way, the interactive parameter display and designing reports is more responsive now.
  • The SingleValueQuery- and MultiValueQuery-Function can now be used to define dynamic default selections in parameter.
  • You can redefine the list of output types that are available for a report
  • Pentaho-Metadata datasources can now accept multi-selection parameter.
  • Our Pentaho-Metadata datasource got a new Advanced mode to calculate the query string in a expression.
  • There’s a whole bunch of new barcode-types available.
  • LibLoader is more aggressive on caching data from HTTP connections. So even if your service does everything wrong when it comes to cache-headers, we will handle that gracefully now. And best of all: In most cases you can “just use it(tm)”. You don’t need to configure a single bit.
  • Thanks to KSK Solutions in Japan, we now have a Japanese translation for the Pentaho Report Designer
  • There is a experimental CDA datasource now. It works, even though it is still a bit flaky in Edit-Mode in the Report Designer.

Now the release is done, and there is only one thing left to do: Doug, please, please upload the product to SourceForge quickly, so that everyone can download it.

Element layouting strategies in Pentaho Reporting

Back in February on the London Pentaho User-Group meeting I promised to make the contents of that presentation available as blog entries. This is the first of these three articles.

The Pentaho Reporting Engine supports several lay-outing strategies to create sophisticated reports easier and to simply the report creation process.

You can change the layout strategy of a band using the “layout” style-key on that band.


A canvas layout positions elements freely on the area of the parent band. Elements have no relationship to each other during the lay-outing. Therefore if an element expands its size, it does not push elements out of the way. Expanding elements always increase the size of the parent band.

Elements inside a Canvas level band are positioned using the position::x and position::y style-keys.

The Canvas layout is the default layout for all new reports and bands.

If you are familiar with HTML and CSS, then think of this layout as a collection of absolutely positioned elements.


Elements in a block layout band are laid out one after each other vertically. Block-level elements span the full width of the parent band. If a element expands it pushes all other elements down so that no element overlaps the other elements.

Master- and SubReport elements as well as Groups are always laid as block elements.

If you are familiar with HTML and CSS, think of this layout as a set of




In an inline formatting context, boxes are laid out horizontally, one after the other, beginning at the top of a containing block. Horizontal margins, borders, and padding are respected between these boxes. The boxes may be aligned vertically in different ways: their bottoms or tops may be aligned, or the baselines of text within them may be aligned. The rectangular area that contains the boxes that form a line is called a line box.

A inline element that is placed in a non-inline layout band creates an artificial paragraph to wrap around this element during the lay-outing process. The most common use of this layout strategy is to produce rich-text content from several independent report elements.

If you are familiar with HTML and CSS, think of this layout as a set of elements.


The row layout positions elements one after each other on the horizontal axis. All elements are printed in a single row, expanding their height as needed. If all elements should expand to the height of tallest element, set the min-height to “100%”.

Row-layout is a natural match for list reports, where multiple columns of data should be printed per row of data. When a element expands its width all other elements get pushed to the right.

If you are familiar with HTML and CSS, think of this layout as a HTML table with a single row of data.

When you use a row-layout for your list-reports, you will no longer need to layout elements manually. To create spacing between elements use either padding on your elements or place a empty band as padding element into the row layout band. The report design wizard makes use of the row-layout to position elements in the details band and details-header bands.

Combining layout strategies for better effects

You can combine several layout strategies in one root element by adding extra bands to your report. All elements placed into these bands will be governed by the band’s layout setting.

How to avoid that dynamic-height elements overlap other elements

You can use this to avoid overlapping elements in your report whenever you use “dynamic-height” elements and to create proper table-rows so that elements of the second row get pushed down by the expanding content of the first row.

Use the following steps to create a two-row details band.

  1. make your details band a block-layout by setting the layout-style of this band to “block”.
  2. Add two bands.
  3. Add the elements for the first row into the first band, and all elements for the second row into the second band.

That’s it. When your first row elements expand, your second row elements will be pushed down.

Download a sample report to see the row- and block-layouter in action.