Filing and Printing Documents - Beginning Java - page 1195

sketchBook.append(new SketchCoverPage(theApp), pageFormat);
Apart from the first statement and the last statement that appends the Printable object that represents
the page painter, all this code is essentially the same as the code in the previous example for creating the
PageFormat object for the cover page.
To add the second page of the sketch to the Book object, you could write the following:
sketchBook.append(theApp.getView(), pageFormat);
The arguments to the append() method specify that the view object prints the page, and that the
PageFormat object that should be used is the one stored in the pageFormat field in the SketcherFrame
class.
Now that you have assembled the topic containing the two pages for the print job, you can tell the Print-
erJob object that you want to print the topic:
printJob.setPageable(sketchBook); // The topic is the source of pages
All you need to do is call the print() method for the PrinterJob object to start printing. To expedite
printing, the PrinterJob object communicates with the Book object to get the number of pages to be printed
and to get the page painter and page format appropriate to print each page. The total number of pages is
returned by the getNumberOfPages() method for the Book object. In this case it always returns 2 because a
printed sketch consists of just a cover page plus the sketch. A reference to the Printable object for a given
page index is returned by the getPrintable() method for the Book object, and the PageFormat object for
a given page index is returned by the getPageFormat() method. Obviously, in the case of Sketcher, using a
Book object doesn't offer much advantage over the Pageable object that you used in the previous example.
In situations where you have more complex documents with a lot of pages with diverse formats, it can make
things much easier.
You use the other version of append() for a Book object to add a given number of pages to a book that is
produced by a single Printable object, and where all the pages have the same format. Here's an example:
Book book = new Book();
book.append(painter, pageFormat, pageCount);
Here the painter argument is a reference of type Printable that prints pageCount pages all with the
same format, pageFormat . A typical instance where you might use this might be a long text document. The
document could consist of many pages, but they all are printed with the same page format. The view object
for the document typically provides a method to figure out the number of pages that are necessary to output
the document.
Printing Swing Components
Printing components is easier than you might think. Swing components are particularly easy to print because
they already know how to draw themselves. You should not call a Swing component's paint() method
when you want to print it, though. Rendering of Swing components is buffered by default to improve the
efficiency of displaying them but printing one by calling its paint() method adds a lot of unnecessary over-
head to the printing operation. Instead you should call the print() method that is defined in the JCompon-
ent class. This renders the component directly to the graphics context that is passed as an argument, so there