Java LanguageJava Print Service

Introduction

The Java Print Service API provides functionalities to discover print services and send print requests for them.

It includes extensible print attributes based on the standard attributes specified in the Internet Printing Protocol (IPP) 1.1 from the IETF Specification, RFC 2911.

Discovering the available print services

To discovery all the available print services, we can use the PrintServiceLookup class. Let's see how:

import javax.print.PrintService;
import javax.print.PrintServiceLookup;

public class DiscoveringAvailablePrintServices {

    public static void main(String[] args) {
        discoverPrintServices();
    }

    public static void discoverPrintServices() {
        PrintService[] allPrintServices = PrintServiceLookup.lookupPrintServices(null, null);
        
        for (Printservice printService : allPrintServices) {
            System.out.println("Print service name: " + printService.getName());
        }
    }

}

This program, when executed on a Windows environment, will print something like this:

Print service name: Fax
Print service name: Microsoft Print to PDF
Print service name: Microsoft XPS Document Viewer

Discovering the default print service

To discovery the default print service, we can use the PrintServiceLookup class. Let's see how::

import javax.print.PrintService;
import javax.print.PrintServiceLookup;

public class DiscoveringDefaultPrintService {

    public static void main(String[] args) {
        discoverDefaultPrintService();
    }

    public static void discoverDefaultPrintService() {
        PrintService defaultPrintService = PrintServiceLookup.lookupDefaultPrintService();
        System.out.println("Default print service name: " + defaultPrintService.getName());
    }

}

Creating a print job from a print service

A print job is a request of printing something in a specific print service. It consists, basically, by:

After picking-up the right print service instance, we can request the creation of a print job:

DocPrintJob printJob = printService.createPrintJob();

The DocPrintJob interface provide us the print method:

printJob.print(doc, pras);

The doc argument is a Doc: the data that will be printed.

And the pras argument is a PrintRequestAttributeSet interface: a set of PrintRequestAttribute. Are examples of print request attributes:

  • amount of copies (1, 2 etc),
  • orientation (portrait or landscape)
  • chromacity (monochrome, color)
  • quality (draft, normal, high)
  • sides (one-sided, two-sided etc)
  • and so on...

The print method may throw a PrintException.

Building the Doc that will be printed

Doc is an interface and the Java Print Service API provide a simple implementation called SimpleDoc.

Every Doc instance is basically made of two aspects:

  • the print data content itself (an E-mail, an image, a document etc)
  • the print data format, called DocFlavor (MIME type + Representation class).

Before creating the Doc object, we need to load our document from somewhere. In the example, we will load an specific file from the disk:

FileInputStream pdfFileInputStream = new FileInputStream("something.pdf");

So now, we have to choose a DocFlavor that matches our content. The DocFlavor class has a bunch of constants to represent the most usual types of data. Let's pick the INPUT_STREAM.PDF one:

DocFlavor pdfDocFlavor = DocFlavor.INPUT_STREAM.PDF;

Now, we can create a new instance of SimpleDoc:

Doc doc = new SimpleDoc(pdfFileInputStream, pdfDocFlavor , null);

The doc object now can be sent to the print job request (see Creating a print job from a print service).

Defining print request attributes

Sometimes we need to determine some aspects of the print request. We will call them attribute.

Are examples of print request attributes:

  • amount of copies (1, 2 etc),
  • orientation (portrait or landscape)
  • chromacity (monochrome, color)
  • quality (draft, normal, high)
  • sides (one-sided, two-sided etc)
  • and so on...

Before choosing one of them and which value each one will have, first we need to build a set of attributes:

PrintRequestAttributeSet pras = new HashPrintRequestAttributeSet();

Now we can add them. Some examples are:

pras.add(new Copies(5));
pras.add(MediaSize.ISO_A4);
pras.add(OrientationRequested.PORTRAIT);
pras.add(PrintQuality.NORMAL);

The pras object now can be sent to the print job request (see Creating a print job from a print service).

Listening print job request status change

For the most printing clients, is extremely useful to know if a print job has finished or failed.

The Java Print Service API provide some functionalities to get informed about these scenarios. All we have to do is:

  • provide an implementation for PrintJobListener interface and
  • register this implementation at the print job.

When the print job state changes, we will be notified. We can do anything is needed, for example:

  • update a user interface,
  • start another business process,
  • record something in the database,
  • or simply log it.

In the example bellow, we will log every print job status change:

import javax.print.event.PrintJobEvent;
import javax.print.event.PrintJobListener;

public class LoggerPrintJobListener implements PrintJobListener {

    // Your favorite Logger class goes here!
    private static final Logger LOG = Logger.getLogger(LoggerPrintJobListener.class);


    public void printDataTransferCompleted(PrintJobEvent pje) {
        LOG.info("Print data transfer completed ;) ");
    }

    public void printJobCompleted(PrintJobEvent pje) {
        LOG.info("Print job completed =) ");
    }

    public void printJobFailed(PrintJobEvent pje) {
        LOG.info("Print job failed =( ");
    }

    public void printJobCanceled(PrintJobEvent pje) {
        LOG.info("Print job canceled :| ");
    }

    public void printJobNoMoreEvents(PrintJobEvent pje) {
        LOG.info("No more events to the job ");
    }

    public void printJobRequiresAttention(PrintJobEvent pje) {
        LOG.info("Print job requires attention :O ");
    }
}

Finally, we can add our print job listener implementation on the print job before the print request itself, as follows:

DocPrintJob printJob = printService.createPrintJob();

printJob.addPrintJobListener(new LoggerPrintJobListener());

printJob.print(doc, pras);

The PrintJobEvent pje argument

Notice that every method has a PrintJobEvent pje argument. We don't use it in this example for simplicity purposes, but you can use it to explore the status. For example:

pje.getPrintJob().getAttributes();

Will return a PrintJobAttributeSet object instance and you can run them in a for-each way.


Another way to achieve the same goal

Another option to achieve the same goal is extending the PrintJobAdapter class, as the name says, is an adapter for PrintJobListener. Implementing the interface we compulsorily have to implement all of them. The advantage of this way it's we need to override only the methods we want. Let's see how it works:

import javax.print.event.PrintJobEvent;
import javax.print.event.PrintJobAdapter;

public class LoggerPrintJobAdapter extends PrintJobAdapter {

    // Your favorite Logger class goes here!
    private static final Logger LOG = Logger.getLogger(LoggerPrintJobAdapter.class);

    public void printJobCompleted(PrintJobEvent pje) {
        LOG.info("Print job completed =) ");
    }

    public void printJobFailed(PrintJobEvent pje) {
        LOG.info("Print job failed =( ");
    }
}

Notice that we override only some specific methods.

As the same way in the example implementing the interface PrintJobListener, we add the listener to the print job before sending it to print:

printJob.addPrintJobListener(new LoggerPrintJobAdapter());

printJob.print(doc, pras);