GNU Classpath - javax.print

Provides the basic interfaces and classes of the Java Print Service API.

The Java Print Service API enables programmers to:

- Discover print services for printing to printer devices and to output streams. The discovery process can be constrained to return only print services supporting specific document formats or printing attributes.
- Print client-formatted print data like Postscript, PDF or various image formats and service-formatted print data from Java.
- Submit, cancel and monitor single and multi document print jobs.
- Provide users a graphical print service browser with printing attribute selection.

## Print Service Discovery

Print service types in the JPS API:

- PrintService:
  The base interface describing a print service capable of printing a supplied document for a given document format to the printer device it is representing.
- MultiDocPrintService:
  Extends the PrintService interface and provides a print service which is capable of printing multiple documents as one print job to its printer device.
- StreamPrintService:
  Extends the PrintService interface and provides a print service which is capable of printing into a supplied output stream instead of to a physical printer device.

#### PrintService, MultiDocPrintService

Discovery is done by the use of the static methods in the PrintServiceLookup class. The discovery process can be constrained by supplying the document formats and printing attributes that need to be supported by the returned print service. Furthermore the lookupDefaultPrintService() method enables to lookup the default print service of the platforms printing system.

#### StreamPrintService

StreamPrintService provides the same functionality as a print service for output to a supplied `OutputStream`. Available stream print services are discovered via the static methods in the StreamPrintServiceFactory factory. The query can be constrained by supplying the the requested document format support and the needed output format.

## Document formats

The format of the printing documents are specified by the DocFlavor class in the JPS API. It provides the description of the format in which the print data will be supplied in a print job to the print service and consists of two parts:

- The MIME type (Multipurpose Internet Mail Extensions types as described in RFC 2045/2046) specifying the media format of the print data.
- The representation class name which is the fully qualified name of the class providing the print data to the print job. For example if the print data is supplied as a byte array the representation class name will be "[B" or for an input stream "java.io.InputStream".

The Java Print Service API differentiates between two types of print data, client-formatted and service-formatted. Client-formatted print data is already provided in a formatted representation by the client e.g. in an image format or as postscript. For service-formatted print data, the Java Print Service implementation produces the formatted print data. Here the doc flavor's representation class name does specify an interface instead of the actual print data source. The print service will call the methods of the given implementation of this interface with a special Graphics object capable of producing formatted print data from the graphics routines inside the interface methods.

## Printing attributes

Print services as well as print jobs report their state and capabilities by the way of supplying printing attributes. Also the behaviour of print jobs (like how many copies should be printed) is controlled via printing attributes. For these requirements the JPS API defines different roles of attributes and common syntax classes in the package `javax.print.attribute`. The actual available printing attributes are implemented in the `javax.print.attribute.standard` package.

- Print service attributes:
  These printing attributes of role PrintServiceAttribute report the status and other informations of a PrintService. Example for informations available in the print services attributes are the attribute `PagesPerMinute` providing the number of pages a printer can print per minute. Status attributes like the `PrinterState` attribute gives the current state (e.g. printer currently processes or is idle) of the printer.
- Print job attributes:
  Print job attributes of role PrintJobAttribute inform about the status of given print job. For example the `NumberOfInterveningJobs` attribute provides the number of jobs ahead in the print service queue before this job. Status attributes like the `JobState` attribute gives the current state of the print job (like pending, processing or canceled).
- Print request attributes:
  The attributes of role PrintRequestAttribute specify the behaviour of a complete print job. The print request attributes apply to all documents in a print job, whereas the doc attributes only apply to the specific document in a print job. Most of the print request attributes are also doc attributes and therefore implementing both attribute role interfaces.
- Doc attributes:
  As described above the PrintJobAttribute attributes are specific to a single document in the print job.

## Example of using the API

    import java.io.*;

    import javax.print.*;
    import javax.print.attribute.*;
    import javax.print.attribute.standard.*;
    import javax.print.event.*;

    public class Beispiel
    {
      public static void main(String[] args)
      {
        // Using the predefined doc flavor for postscript mimetype
        DocFlavor flavor = DocFlavor.INPUT_STREAM.POSTSCRIPT;

        // Looking for printservice supporting this doc flavor
        PrintService[] services = PrintServiceLookup.lookupPrintServices(flavor, null);

        // Just take the first
        PrintService service = services[0];
        System.out.println("Name :" + service.getName());

        try
          {
            // Create a print job
            DocPrintJob job = service.createPrintJob();

            // We want to print a file so we construct an inputstream
            // on the file to supply the print data as given in the doc flavor
            File file = new File("File.ps");
            InputStream stream = new FileInputStream(file);

            // Build a attribute set with the wanted printing attributes
            HashPrintRequestAttributeSet attr = new HashPrintRequestAttributeSet();
            attr.add(new Copies(2)); // two copies
            attr.add(new PageRanges(2, 7)); // only the 2-7 pages

            // Construct a doc object with the provided class SimpleDoc
            SimpleDoc doc = new SimpleDoc(stream, flavor, null);

            // register us as the print - use the adapter class
            // and override the interesing failure condition
            job.addPrintJobListener(new PrintJobAdapter()
            {
              public void printJobFailed(PrintJobEvent arg0)
              {
                System.out.println("The PrintJob failed.");
              }
            });

            // start the printing process
            job.print(doc, attr);

            // lets assume we want to cancel it
            if (job instanceof CancelablePrintJob)
              {
                CancelablePrintJob cancelJob = (CancelablePrintJob) job;
                cancelJob.cancel();
              }

          }
        catch (PrintException e)
        {
          e.printStackTrace();
        }
        catch (FileNotFoundException e)
        {
          e.printStackTrace();
        }
      }
    }

Since: 1.4