Basic Ideas
The goal is to design a flexible java library which can be
used to easily create multiple kinds of reports. To server this end, the
library relies heavily on object oriented methodology, so that components can be
extended and customized to individual situations. The basic hierarchy is
as follows:
| FieldRenderer |
This is a class that knows how to draw a single piece of
information on a report. For example: a string, a number,
picture. You initialize a field renderer by giving it the data that
it needs to print. Then, you can pass it a graphics object, a
rectangle, and what justification to use, and it draws the data item in
the given rectangle.
Example: CommentRenderer |
| ReportDataModel |
This is a class that wraps around data to provide reports a
single interface to the data which the report prints.
Example: SQLReportDataModel - Takes a select statement and a
database connection, and creates a data model where each row is
interpreted as a record, and each field as a separate field in the printed
report. |
| RecordsRenderer |
This is a class that knows how to draw a record from a
ReportDataModel. The RecordsRenderer controls the arrangement of the
data in a record with respect to one another.
Example: HorizRecordsRenderer - Draws the fields next to one another
in a row. Can draw lines around each field, or each row. |
| AbstractReportItem |
This class is passed to the Report for printing.
It is the basic printed unit on a Report. Classes descended from the
AbstractReportItem know how to do page breaks, and control the printing of
each record.
Examples: DefaultRecordsItem - takes a ReportDataModel and a
RecordsRenderer, and knows how to print the records as requested by the
report. |
| Report |
The highest class in the hierarchy. This class takes
and print a collection of AbstractReportItems. |
The basic stages in creating a report are as follows:
- Put all the data you want printed into ReportDataModels.
- Create RecordsRenderers to control how the data will be printed.
- Create ReportDataItems for each section printed on the report.
- Put them in a Report object.
- Print the report.
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