src/java.desktop/windows/classes/sun/print/PrintServiceLookupProvider.java

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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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package sun.print;

import java.util.ArrayList;

import javax.print.DocFlavor;
import javax.print.MultiDocPrintService;
import javax.print.PrintService;
import javax.print.PrintServiceLookup;
import javax.print.attribute.Attribute;
import javax.print.attribute.AttributeSet;
import javax.print.attribute.HashPrintRequestAttributeSet;
import javax.print.attribute.HashPrintServiceAttributeSet;
import javax.print.attribute.PrintRequestAttribute;
import javax.print.attribute.PrintRequestAttributeSet;
import javax.print.attribute.PrintServiceAttribute;
import javax.print.attribute.PrintServiceAttributeSet;
import javax.print.attribute.standard.PrinterName;

import sun.awt.util.ThreadGroupUtils;

public final class PrintServiceLookupProvider extends PrintServiceLookup {

    private PrintService defaultPrintService;
    private PrintService[] printServices; /* includes the default printer */

    static {
        loadAWTLibrary();
    }

    @SuppressWarnings("restricted")
    private static void loadAWTLibrary() {
        System.loadLibrary("awt");
    }

    /* The singleton win32 print lookup service.
     * Code that is aware of this field and wants to use it must first
     * see if its null, and if so instantiate it by calling a method such as
     * javax.print.PrintServiceLookup.defaultPrintService() so that the
     * same instance is stored there.
     */
    private static PrintServiceLookupProvider win32PrintLUS;

    /* Think carefully before calling this. Preferably don't call it. */
    public static PrintServiceLookupProvider getWin32PrintLUS() {
        if (win32PrintLUS == null) {
            /* This call is internally synchronized.
             * When it returns an instance of this class will have
             * been instantiated - else there's a JDK internal error.
             */
            PrintServiceLookup.lookupDefaultPrintService();
        }
        return win32PrintLUS;
    }

    public PrintServiceLookupProvider() {

        if (win32PrintLUS == null) {
            win32PrintLUS = this;

            // start the local printer listener thread
            Thread thr = new Thread(ThreadGroupUtils.getRootThreadGroup(),
                                    new PrinterChangeListener(),
                                    "PrinterListener", 0, false);
            thr.setContextClassLoader(null);
            thr.setDaemon(true);
            thr.start();

            // start the remote printer listener thread
            Thread thr1 = new Thread(ThreadGroupUtils.getRootThreadGroup(),
                                    new RemotePrinterChangeListener(),
                                    "RemotePrinterListener", 0, false);
            thr1.setContextClassLoader(null);
            thr1.setDaemon(true);
            thr1.start();
        } /* else condition ought to never happen! */
    }

    /* Want the PrintService which is default print service to have
     * equality of reference with the equivalent in list of print services
     * This isn't required by the API and there's a risk doing this will
     * lead people to assume its guaranteed.
     */
    @Override
    public synchronized PrintService[] getPrintServices() {
        if (printServices == null) {
            refreshServices();
        }
        return printServices;
    }

    private synchronized void refreshServices() {
        String[] printers = getAllPrinterNames();
        if (printers == null) {
            // In Windows it is safe to assume no default if printers == null so we
            // don't get the default.
            invalidateServices();
            printServices = new PrintService[0];
            return;
        }

        PrintService[] newServices = new PrintService[printers.length];
        PrintService defService = getDefaultPrintService();
        for (int p = 0; p < printers.length; p++) {
            if (defService != null &&
                printers[p].equals(defService.getName())) {
                newServices[p] = defService;
            } else {
                if (printServices == null) {
                    newServices[p] = new Win32PrintService(printers[p]);
                } else {
                    int j;
                    for (j = 0; j < printServices.length; j++) {
                        if ((printServices[j]!= null) &&
                            (printers[p].equals(printServices[j].getName()))) {
                            newServices[p] = printServices[j];
                            printServices[j] = null;
                            break;
                        }
                    }
                    if (j == printServices.length) {
                        newServices[p] = new Win32PrintService(printers[p]);
                    }
                }
            }
        }

        invalidateServices();
        printServices = newServices;
    }

    private void invalidateServices() {
        // Look for deleted services and invalidate these
        if (printServices != null) {
            for (int j=0; j < printServices.length; j++) {
                if ((printServices[j] instanceof Win32PrintService) &&
                    (!printServices[j].equals(defaultPrintService))) {

                    ((Win32PrintService)printServices[j]).invalidateService();
                }
            }
        }
    }


    public synchronized PrintService getPrintServiceByName(String name) {

        if (name == null || name.isEmpty()) {
            return null;
        } else {
            /* getPrintServices() is now very fast. */
            PrintService[] printServices = getPrintServices();
            for (int i=0; i<printServices.length; i++) {
                if (printServices[i].getName().equals(name)) {
                    return printServices[i];
                }
            }
            return null;
        }
    }

    @SuppressWarnings("unchecked") // Cast to Class<PrintServiceAttribute>
    boolean matchingService(PrintService service,
                            PrintServiceAttributeSet serviceSet) {
        if (serviceSet != null) {
            Attribute [] attrs =  serviceSet.toArray();
            Attribute serviceAttr;
            for (int i=0; i<attrs.length; i++) {
                serviceAttr
                    = service.getAttribute((Class<PrintServiceAttribute>)attrs[i].getCategory());
                if (serviceAttr == null || !serviceAttr.equals(attrs[i])) {
                    return false;
                }
            }
        }
        return true;
    }

    @Override
    public PrintService[] getPrintServices(DocFlavor flavor,
                                           AttributeSet attributes) {

        PrintRequestAttributeSet requestSet = null;
        PrintServiceAttributeSet serviceSet = null;

        if (attributes != null && !attributes.isEmpty()) {

            requestSet = new HashPrintRequestAttributeSet();
            serviceSet = new HashPrintServiceAttributeSet();

            Attribute[] attrs = attributes.toArray();
            for (int i=0; i<attrs.length; i++) {
                if (attrs[i] instanceof PrintRequestAttribute) {
                    requestSet.add(attrs[i]);
                } else if (attrs[i] instanceof PrintServiceAttribute) {
                    serviceSet.add(attrs[i]);
                }
            }
        }

        /*
         * Special case: If client is asking for a particular printer
         * (by name) then we can save time by getting just that service
         * to check against the rest of the specified attributes.
         */
        PrintService[] services = null;
        if (serviceSet != null && serviceSet.get(PrinterName.class) != null) {
            PrinterName name = (PrinterName)serviceSet.get(PrinterName.class);
            PrintService service = getPrintServiceByName(name.getValue());
            if (service == null || !matchingService(service, serviceSet)) {
                services = new PrintService[0];
            } else {
                services = new PrintService[1];
                services[0] = service;
            }
        } else {
            services = getPrintServices();
        }

        if (services.length == 0) {
            return services;
        } else {
            ArrayList<PrintService> matchingServices = new ArrayList<>();
            for (int i=0; i<services.length; i++) {
                try {
                    if (services[i].
                        getUnsupportedAttributes(flavor, requestSet) == null) {
                        matchingServices.add(services[i]);
                    }
                } catch (IllegalArgumentException e) {
                }
            }
            services = new PrintService[matchingServices.size()];
            return matchingServices.toArray(services);
        }
    }

    /*
     * return empty array as don't support multi docs
     */
    @Override
    public MultiDocPrintService[]
        getMultiDocPrintServices(DocFlavor[] flavors,
                                 AttributeSet attributes) {
        return new MultiDocPrintService[0];
    }


    @Override
    public synchronized PrintService getDefaultPrintService() {

        // Windows does not have notification for a change in default
        // so we always get the latest.
        String defaultPrinter = getDefaultPrinterName();
        if (defaultPrinter == null) {
            return null;
        }

        if ((defaultPrintService != null) &&
            defaultPrintService.getName().equals(defaultPrinter)) {

            return defaultPrintService;
        }

         // Not the same as default so proceed to get new PrintService.

        // clear defaultPrintService
        defaultPrintService = null;

        if (printServices != null) {
            for (int j=0; j<printServices.length; j++) {
                if (defaultPrinter.equals(printServices[j].getName())) {
                    defaultPrintService = printServices[j];
                    break;
                }
            }
        }

        if (defaultPrintService == null) {
            defaultPrintService = new Win32PrintService(defaultPrinter);
        }
        return defaultPrintService;
    }

    private final class PrinterChangeListener implements Runnable {
        @Override
        public void run() {
            notifyLocalPrinterChange(); // busy loop in the native code
        }
    }

    private final class RemotePrinterChangeListener implements Runnable {
        @Override
        public void run() {
            notifyRemotePrinterChange(); // busy loop in the native code
        }
    }

    private native String getDefaultPrinterName();
    private native String[] getAllPrinterNames();
    private native void notifyLocalPrinterChange();
    private native void notifyRemotePrinterChange();
}