A report can define a number of groups. Groups represent named expressions that
determine the visual grouping of the related report data. Once declared, groups can be
referred to throughout the report. JasperAssistant collects group definitions under a
Groups node in the
Outline View. New groups
can be added by using the context menu associated to this node.
A data group is identified using a group expression. Two consecutive data source lines are considered to be in the same group, if the group expression evaluates to the same value for both lines.
The grouping mechanism does not perform any sorting on the data supplied by the data source. The data provided by the data source must be already sorted so that the desired groups can be formed.
By declaring a group, two additional report sections can be added to the report:
Group Header and
Group Footer(Section 6.10, “Report Sections”).
Name of the group declaration as it is used to refer to the group throughout the report.
Expression that determines the grouping of report data.
Min Height To Start New Page
Minimum amount of vertical space needed at the bottom of the column in order to place the group header on the current column. The amount is specified in report units.
Reprint Header On Each Page
Flag that indicates whether the group header should be reprinted at the beginning of each new page.
Reset Page Number
Flag that indicates whether the page number should be reset and group header printed at the beginning of a new page.
Start New Column
Flag that indicates whether the group header should be printed always on a new column.
Start New Page
Flag that indicates whether the group header should be printed always on a new page.