NESTED TABLES in Java

Making Denso QR Bar Code in Java NESTED TABLES

There was a time when rowspan wasn t supported for PdfPCells. The only way to work around this was to use nested tables. Cells 1.1 and 1.2 in figure 4.10 are part of a

nested table. So are cells 12.1 and 12.2. Because of this, cells 13, 14, and 15 look as if they have their rowspan set to 2. Looking at next listing, you ll immediately see the difference between the nested table in cell 1 and the nested table in cell 12.

PdfPTable table = new PdfPTable(4); PdfPTable nested1 = new PdfPTable(2); Creates table nested1.addCell("1.1"); for cell 1 nested1.addCell("1.2"); PdfPTable nested2 = new PdfPTable(1); Creates table nested2.addCell("12.1"); for cell 12 nested2.addCell("12.2"); for (int k = 0; k < 16; ++k) { if (k == 1) { table.addCell(nested1); Adds tables } else if (k == 12) { as cell table.addCell(new PdfPCell(nested2)); } else { table.addCell("cell " + k); } } document.add(table);

Just like with the Image object, the padding is 2 pt when the PdfPTable is added with addCell() directly. The padding is 0 pt when you wrap the table in a PdfPCell first.

You can use nested tables to create layouts that are tabular, but that don t fit in a traditional grid. Figure 4.11 is an example of such a layout.

This layout is created using the next listing, which is an example of deep nesting. A table is nested inside a nested table.

public void createPdf(String filename) throws SQLException, DocumentException, IOException { DatabaseConnection connection = new HsqldbConnection("filmfestival"); Document document = new Document(); PdfWriter.getInstance(document, new FileOutputStream(filename)); document.open(); List days = PojoFactory.getDays(connection); for (Date day : days) { document.add(getTable(connection, day)); document.newPage(); } document.close(); connection.close(); } public PdfPTable getTable( DatabaseConnection connection, Date day) throws SQLException, DocumentException, IOException { Master table PdfPTable table = new PdfPTable(1); ... List screenings = PojoFactory.getScreenings(connection, day); for (Screening screening : screenings) { table.addCell(getTable(connection, screening)); } return table; } private PdfPTable getTable( DatabaseConnection connection, Screening screening) throws DocumentException, IOException { PdfPTable table = new PdfPTable(4); ... Movie movie = screening.getMovie(); Table nested PdfPCell cell = new PdfPCell(); inside master cell.addElement(fullTitle(screening)); table ... table.addCell(cell); ... return table; } private static PdfPTable fullTitle(Screening screening) throws DocumentException { PdfPTable table = new PdfPTable(3); Deep nested table ... return table; }

The table created with the fullTitle() method was added with the addElement() method. The effect is different from adding a PdfPTable as a parameter of the addCell() method or the PdfPCell constructor. With addElement(), the table is

added to the ColumnText object of the cell, and you can add other elements to the same cell. You ve now worked with some small, almost academic, table examples to demonstrate the properties of tables and cells, but once you start working with real-world examples, tables can get really large. In the next section, we ll discuss tips and tricks that are important as soon as a table spans multiple pages.

The table in figure 4.11 has a header with a date. If you download the example and generate the PDF on your own computer, you ll see that the table with all the movies spans more than one page for most of the days. The table is nicely split, but unfortunately the header isn t repeated. In this section, you ll fix this, and also add a footer while you re at it.

Figure 4.12 is another overview of movie screenings on a specific day. The date is shown in the first row. The second row consists of headers that describe the content of the columns: Location, Time, Run Length, Title, and so on. The same information is also added as a footer.