13.3 Printing with the Java 1.4 API

Example 13-3 is a further subclass of our Julia set component, which once again overrides the print( ) method and this time uses the Java 1.4 Printing API to produce the printed output shown in Figure 13-3. In addition, it defines a save( ) method that uses the Java 1.4 Printing API to print the image of the Julia set directly to a PostScript file. The actual printing of the image is done by the PrintableComponent class inherited from the previous example: what is different in this example is the way the Printable object is sent to a printer.

Figure 13-3. A Julia set printed with the Java 1.4 API

The print( ) and save( ) methods start by obtaining an appropriate PrintService object that represents a printer or print engine that can print to a file. Both methods then call the printToService( ) method, which uses the inherited PrintableComponent class to print the Julia set to the PrintService. One interesting feature of this method is its use of a PrintJobListener to monitor the progress of the print job and display its current status in a dialog box.

Example 13-3. JuliaSet3.java

package je3.print; import javax.swing.*; import java.awt.print.*;     // Java 1.4 can use the 1.2 Printable API import javax.print.*;        // Java 1.4 API  import javax.print.event.*;   import javax.print.attribute.*; import javax.print.attribute.standard.*; import java.io.*; /**  * This class extends JuliaSet2, and its print( ) and save( ) methods demonstrate  * the Java 1.4 printing API.  **/ public class JuliaSet3 extends JuliaSet2 {     public JuliaSet3( ) { super(-.7, -.25); }     // This method overrides JuliaSet2.print( ) and demonstrates the javax.print     // printing API.     public void print( ) {         // Get a list of all printers that can handle Printable objects.         DocFlavor flavor = DocFlavor.SERVICE_FORMATTED.PRINTABLE;         PrintService[  ] services =             PrintServiceLookup.lookupPrintServices(flavor, null);         // Set some printing attributes         PrintRequestAttributeSet printAttributes =             new HashPrintRequestAttributeSet( );         printAttributes.add(OrientationRequested.LANDSCAPE); // landscape mode         printAttributes.add(Chromaticity.MONOCHROME);        // print in mono         // Display a dialog that allows the user to select one of the         // available printers and to edit the default attributes         PrintService service = ServiceUI.printDialog(null, 100, 100,                                                      services, null, null,                                                      printAttributes);         // If the user canceled, don't do anything         if (service == null) return;         // Now call a method defined below to finish the printing         printToService(service, printAttributes);     }     // This method is like print( ) above but prints to a PostScript file     // instead of printing to a printer.     public void save( ) throws IOException {         // Find a factory object for printing Printable objects to PostScript.         DocFlavor flavor = DocFlavor.SERVICE_FORMATTED.PRINTABLE;         String format = "application/postscript";         StreamPrintServiceFactory factory = StreamPrintServiceFactory.             lookupStreamPrintServiceFactories(flavor, format)[0];         // Ask the user to select a file and open the selected file         JFileChooser chooser = new JFileChooser( );         if (chooser.showSaveDialog(this)!=JFileChooser.APPROVE_OPTION) return;         File f = chooser.getSelectedFile( );         FileOutputStream out = new FileOutputStream(f);         // Obtain a PrintService that prints to that file         StreamPrintService service = factory.getPrintService(out);         // Do the printing with the method below         printToService(service, null);         // And close the output file.         out.close( );     }     // Print the Julia set to the sepecifed PrintService using the specified     // attributes.     public void printToService(PrintService service,                                PrintRequestAttributeSet printAttributes)     {         // Wrap ourselves in the PrintableComponent class defined by JuliaSet2.         String title = "Julia set for c={" + cx + "," + cy + "}";         Printable printable = new PrintableComponent(this, title);         // Now create a Doc that encapsulates the Printable object and its type         DocFlavor flavor = DocFlavor.SERVICE_FORMATTED.PRINTABLE;         Doc doc = new SimpleDoc(printable, flavor, null);         // Java 1.1 uses PrintJob.         // Java 1.2 uses PrinterJob.         // Java 1.4 uses DocPrintJob. Create one from the service         DocPrintJob job = service.createPrintJob( );         // Set up a dialog box to  monitor printing status         final JOptionPane pane = new JOptionPane("Printing...",                                                   JOptionPane.PLAIN_MESSAGE);         JDialog dialog = pane.createDialog(this, "Print Status");         // This listener object updates the dialog as the status changes         job.addPrintJobListener(new PrintJobAdapter( ) {                 public void printJobCompleted(PrintJobEvent e) {                     pane.setMessage("Printing complete.");                 }                 public void printDataTransferCompleted(PrintJobEvent e) {                     pane.setMessage("Document transfered to printer.");                 }                 public void printJobRequiresAttention(PrintJobEvent e) {                     pane.setMessage("Check printer: out of paper?");                 }                 public void printJobFailed(PrintJobEvent e) {                     pane.setMessage("Print job failed");                 }             });         // Show the dialog, non-modal.         dialog.setModal(false);         dialog.show( );         // Now print the Doc to the DocPrintJob         try {             job.print(doc, printAttributes);         }         catch(PrintException e) {             // Display any errors to the dialog box             pane.setMessage(e.toString( ));         }     } }