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Java example source code file (UnixPrintServiceLookup.java)

This example Java source code file (UnixPrintServiceLookup.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

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Java - Java tags/keywords

arraylist, attribute, bsd_lpd_ng, default_minrefresh, exception, ippprintservice, net, network, print, printername, printing, printservice, security, securitymanager, string, uninitialized, unixprintservice, unixprintservicelookup, util, vector

The UnixPrintServiceLookup.java Java example source code

/*
 * Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

package sun.print;

import java.io.BufferedReader;
import java.io.FileInputStream;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Vector;
import java.security.AccessController;
import java.security.PrivilegedActionException;
import java.security.PrivilegedExceptionAction;
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 javax.print.attribute.standard.PrinterURI;
import java.io.File;
import java.io.FileReader;
import java.net.URL;
import java.nio.file.Files;

/*
 * Remind: This class uses solaris commands. We also need a linux
 * version
 */
public class UnixPrintServiceLookup extends PrintServiceLookup
    implements BackgroundServiceLookup, Runnable {

    /* Remind: the current implementation is static, as its assumed
     * its preferable to minimize creation of PrintService instances.
     * Later we should add logic to add/remove services on the fly which
     * will take a hit of needing to regather the list of services.
     */
    private String defaultPrinter;
    private PrintService defaultPrintService;
    private PrintService[] printServices; /* includes the default printer */
    private Vector lookupListeners = null;
    private static String debugPrefix = "UnixPrintServiceLookup>> ";
    private static boolean pollServices = true;
    private static final int DEFAULT_MINREFRESH = 120;  // 2 minutes
    private static int minRefreshTime = DEFAULT_MINREFRESH;


    static String osname;

    static {
        /* The system property "sun.java2d.print.polling"
         * can be used to force the printing code to poll or not poll
         * for PrintServices.
         */
        String pollStr = java.security.AccessController.doPrivileged(
            new sun.security.action.GetPropertyAction("sun.java2d.print.polling"));

        if (pollStr != null) {
            if (pollStr.equalsIgnoreCase("true")) {
                pollServices = true;
            } else if (pollStr.equalsIgnoreCase("false")) {
                pollServices = false;
            }
        }

        /* The system property "sun.java2d.print.minRefreshTime"
         * can be used to specify minimum refresh time (in seconds)
         * for polling PrintServices.  The default is 120.
         */
        String refreshTimeStr = java.security.AccessController.doPrivileged(
            new sun.security.action.GetPropertyAction(
                "sun.java2d.print.minRefreshTime"));

        if (refreshTimeStr != null) {
            try {
                minRefreshTime = (new Integer(refreshTimeStr)).intValue();
            } catch (NumberFormatException e) {
            }
            if (minRefreshTime < DEFAULT_MINREFRESH) {
                minRefreshTime = DEFAULT_MINREFRESH;
            }
        }

        osname = java.security.AccessController.doPrivileged(
            new sun.security.action.GetPropertyAction("os.name"));
    }

    static boolean isMac() {
        return osname.startsWith("Mac");
    }

    static boolean isSysV() {
        return osname.equals("SunOS");
    }

    static boolean isLinux() {
        return (osname.equals("Linux"));
    }

    static boolean isBSD() {
        return (osname.equals("Linux") ||
                osname.contains("OS X"));
    }

    static final int UNINITIALIZED = -1;
    static final int BSD_LPD = 0;
    static final int BSD_LPD_NG = 1;

    static int cmdIndex = UNINITIALIZED;

    String[] lpcFirstCom = {
        "/usr/sbin/lpc status | grep : | sed -ne '1,1 s/://p'",
        "/usr/sbin/lpc status | grep -E '^[ 0-9a-zA-Z_-]*@' | awk -F'@' '{print $1}'"
    };

    String[] lpcAllCom = {
        "/usr/sbin/lpc status all | grep : | sed -e 's/://'",
        "/usr/sbin/lpc status all | grep -E '^[ 0-9a-zA-Z_-]*@' | awk -F'@' '{print $1}' | sort"
    };

    String[] lpcNameCom = {
        "| grep : | sed -ne 's/://p'",
        "| grep -E '^[ 0-9a-zA-Z_-]*@' | awk -F'@' '{print $1}'"
    };


    static int getBSDCommandIndex() {
        String command  = "/usr/sbin/lpc status all";
        String[] names = execCmd(command);

        if ((names == null) || (names.length == 0)) {
            return BSD_LPD_NG;
        }

        for (int i=0; i<names.length; i++) {
            if (names[i].indexOf('@') != -1) {
                return BSD_LPD_NG;
            }
        }

        return BSD_LPD;
    }


    public UnixPrintServiceLookup() {
        // start the printer listener thread
        if (pollServices) {
            PrinterChangeListener thr = new PrinterChangeListener();
            thr.setDaemon(true);
            thr.start();
            IPPPrintService.debug_println(debugPrefix+"polling turned on");
        }
    }

    /* 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.
     */
    public synchronized PrintService[] getPrintServices() {
        SecurityManager security = System.getSecurityManager();
        if (security != null) {
            security.checkPrintJobAccess();
        }

        if (printServices == null || !pollServices) {
            refreshServices();
        }
        if (printServices == null) {
            return new PrintService[0];
        } else {
            return (PrintService[])printServices.clone();
        }
    }

    private int addPrintServiceToList(ArrayList printerList, PrintService ps) {
        int index = printerList.indexOf(ps);
        // Check if PrintService with same name is already in the list.
        if (CUPSPrinter.isCupsRunning() && index != -1) {
            // Bug in Linux: Duplicate entry of a remote printer
            // and treats it as local printer but it is returning wrong
            // information when queried using IPP. Workaround is to remove it.
            // Even CUPS ignores these entries as shown in lpstat or using
            // their web configuration.
            PrinterURI uri = (PrinterURI)ps.getAttribute(PrinterURI.class);
            if (uri.getURI().getHost().equals("localhost")) {
                IPPPrintService.debug_println(debugPrefix+"duplicate PrintService, ignoring the new local printer: "+ps);
                return index;  // Do not add this.
            }
            PrintService oldPS = (PrintService)(printerList.get(index));
            uri = (PrinterURI)oldPS.getAttribute(PrinterURI.class);
            if (uri.getURI().getHost().equals("localhost")) {
                IPPPrintService.debug_println(debugPrefix+"duplicate PrintService, removing existing local printer: "+oldPS);
                printerList.remove(oldPS);
            } else {
                return index;
            }
        }
        printerList.add(ps);
        return (printerList.size() - 1);
    }


    // refreshes "printServices"
    public synchronized void refreshServices() {
        /* excludes the default printer */
        String[] printers = null; // array of printer names
        String[] printerURIs = null; //array of printer URIs

        getDefaultPrintService();
        if (CUPSPrinter.isCupsRunning()) {
            printerURIs = CUPSPrinter.getAllPrinters();
            if ((printerURIs != null) && (printerURIs.length > 0)) {
                printers = new String[printerURIs.length];
                for (int i=0; i<printerURIs.length; i++) {
                    int lastIndex = printerURIs[i].lastIndexOf("/");
                    printers[i] = printerURIs[i].substring(lastIndex+1);
                }
            }
        } else {
            if (isMac() || isSysV()) {
                printers = getAllPrinterNamesSysV();
            } else { //BSD
                printers = getAllPrinterNamesBSD();
            }
        }

        if (printers == null) {
            if (defaultPrintService != null) {
                printServices = new PrintService[1];
                printServices[0] = defaultPrintService;
            } else {
                printServices = null;
            }
            return;
        }

        ArrayList printerList = new ArrayList();
        int defaultIndex = -1;
        for (int p=0; p<printers.length; p++) {
            if (printers[p] == null) {
                continue;
            }
            if ((defaultPrintService != null)
                && printers[p].equals(getPrinterDestName(defaultPrintService))) {
                defaultIndex = addPrintServiceToList(printerList, defaultPrintService);
            } else {
                if (printServices == null) {
                    IPPPrintService.debug_println(debugPrefix+
                                                  "total# of printers = "+printers.length);

                    if (CUPSPrinter.isCupsRunning()) {
                        try {
                            addPrintServiceToList(printerList,
                                                  new IPPPrintService(printers[p],
                                                                   printerURIs[p],
                                                                   true));
                        } catch (Exception e) {
                            IPPPrintService.debug_println(debugPrefix+
                                                          " getAllPrinters Exception "+
                                                          e);

                        }
                    } else {
                        printerList.add(new UnixPrintService(printers[p]));
                    }
                } else {
                    int j;
                    for (j=0; j<printServices.length; j++) {
                        if (printServices[j] != null) {
                            if (printers[p].equals(getPrinterDestName(printServices[j]))) {
                                printerList.add(printServices[j]);
                                printServices[j] = null;
                                break;
                            }
                        }
                    }

                    if (j == printServices.length) {      // not found?
                        if (CUPSPrinter.isCupsRunning()) {
                            try {
                                addPrintServiceToList(printerList,
                                             new IPPPrintService(printers[p],
                                                                 printerURIs[p],
                                                                 true));
                            } catch (Exception e) {
                                IPPPrintService.debug_println(debugPrefix+
                                                              " getAllPrinters Exception "+
                                                              e);

                            }
                        } else {
                            printerList.add(new UnixPrintService(printers[p]));
                        }
                    }
                }
            }
        }

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

        //if defaultService is not found in printerList
        if (defaultIndex == -1 && defaultPrintService != null) {
            defaultIndex = addPrintServiceToList(printerList, defaultPrintService);
        }

        printServices = (PrintService[])printerList.toArray(
                                      new PrintService[] {});

        // swap default with the first in the list
        if (defaultIndex > 0) {
            PrintService saveService = printServices[0];
            printServices[0] = printServices[defaultIndex];
            printServices[defaultIndex] = saveService;
        }
    }

    private boolean matchesAttributes(PrintService service,
                                      PrintServiceAttributeSet attributes) {

        Attribute [] attrs =  attributes.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;
    }

      /* This checks for validity of the printer name before passing as
       * parameter to a shell command.
       */
      private boolean checkPrinterName(String s) {
        char c;

        for (int i=0; i < s.length(); i++) {
          c = s.charAt(i);
          if (Character.isLetterOrDigit(c) ||
              c == '-' || c == '_' || c == '.' || c == '/') {
            continue;
          } else {
            return false;
          }
        }
        return true;
      }

    /*
     * Gets the printer name compatible with the list of printers returned by
     * the system when we query default or all the available printers.
     */
    private String getPrinterDestName(PrintService ps) {
        if (isMac()) {
            return ((IPPPrintService)ps).getDest();
        }
        return ps.getName();
    }

    /* On a network with many (hundreds) of network printers, it
     * can save several seconds if you know all you want is a particular
     * printer, to ask for that printer rather than retrieving all printers.
     */
    private PrintService getServiceByName(PrinterName nameAttr) {
        String name = nameAttr.getValue();
        if (name == null || name.equals("") || !checkPrinterName(name)) {
            return null;
        }
        /* check if all printers are already available */
        if (printServices != null) {
            for (PrintService printService : printServices) {
                PrinterName printerName =
                    (PrinterName)printService.getAttribute(PrinterName.class);
                if (printerName.getValue().equals(name)) {
                    return printService;
                }
            }
        }
        /* take CUPS into account first */
        if (CUPSPrinter.isCupsRunning()) {
            try {
                return new IPPPrintService(name,
                                           new URL("http://"+
                                                   CUPSPrinter.getServer()+":"+
                                                   CUPSPrinter.getPort()+"/"+
                                                   name));
            } catch (Exception e) {
                IPPPrintService.debug_println(debugPrefix+
                                              " getServiceByName Exception "+
                                              e);
            }
        }
        /* fallback if nothing not having a printer at this point */
        PrintService printer = null;
        if (isMac() || isSysV()) {
            printer = getNamedPrinterNameSysV(name);
        } else {
            printer = getNamedPrinterNameBSD(name);
        }
        return printer;
    }

    private PrintService[]
        getPrintServices(PrintServiceAttributeSet serviceSet) {

        if (serviceSet == null || serviceSet.isEmpty()) {
            return getPrintServices();
        }

        /* Typically expect that if a service attribute is specified that
         * its a printer name and there ought to be only one match.
         * Directly retrieve that service and confirm
         * that it meets the other requirements.
         * If printer name isn't mentioned then go a slow path checking
         * all printers if they meet the reqiremements.
         */
        PrintService[] services;
        PrinterName name = (PrinterName)serviceSet.get(PrinterName.class);
        PrintService defService;
        if (name != null && (defService = getDefaultPrintService()) != null) {
            /* To avoid execing a unix command  see if the client is asking
             * for the default printer by name, since we already have that
             * initialised.
             */

            PrinterName defName =
                (PrinterName)defService.getAttribute(PrinterName.class);

            if (defName != null && name.equals(defName)) {
                if (matchesAttributes(defService, serviceSet)) {
                    services = new PrintService[1];
                    services[0] = defService;
                    return services;
                } else {
                    return new PrintService[0];
                }
            } else {
                /* Its not the default service */
                PrintService service = getServiceByName(name);
                if (service != null &&
                    matchesAttributes(service, serviceSet)) {
                    services = new PrintService[1];
                    services[0] = service;
                    return services;
                } else {
                    return new PrintService[0];
                }
            }
        } else {
            /* specified service attributes don't include a name.*/
            Vector matchedServices = new Vector();
            services = getPrintServices();
            for (int i = 0; i< services.length; i++) {
                if (matchesAttributes(services[i], serviceSet)) {
                    matchedServices.add(services[i]);
                }
            }
            services = new PrintService[matchedServices.size()];
            for (int i = 0; i< services.length; i++) {
                services[i] = (PrintService)matchedServices.elementAt(i);
            }
            return services;
        }
    }

    /*
     * If service attributes are specified then there must be additional
     * filtering.
     */
    public PrintService[] getPrintServices(DocFlavor flavor,
                                           AttributeSet attributes) {
        SecurityManager security = System.getSecurityManager();
        if (security != null) {
          security.checkPrintJobAccess();
        }
        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]);
                }
            }
        }

        PrintService[] services = getPrintServices(serviceSet);
        if (services.length == 0) {
            return services;
        }

        if (CUPSPrinter.isCupsRunning()) {
            ArrayList 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 (PrintService[])matchingServices.toArray(services);

        } else {
            // We only need to compare 1 PrintService because all
            // UnixPrintServices are the same anyway.  We will not use
            // default PrintService because it might be null.
            PrintService service = services[0];
            if ((flavor == null ||
                 service.isDocFlavorSupported(flavor)) &&
                 service.getUnsupportedAttributes(flavor, requestSet) == null)
            {
                return services;
            } else {
                return new PrintService[0];
            }
        }
    }

    /*
     * return empty array as don't support multi docs
     */
    public MultiDocPrintService[]
        getMultiDocPrintServices(DocFlavor[] flavors,
                                 AttributeSet attributes) {
        SecurityManager security = System.getSecurityManager();
        if (security != null) {
          security.checkPrintJobAccess();
        }
        return new MultiDocPrintService[0];
    }


    public synchronized PrintService getDefaultPrintService() {
        SecurityManager security = System.getSecurityManager();
        if (security != null) {
          security.checkPrintJobAccess();
        }

        // clear defaultPrintService
        defaultPrintService = null;
        String psuri = null;

        IPPPrintService.debug_println("isRunning ? "+
                                      (CUPSPrinter.isCupsRunning()));
        if (CUPSPrinter.isCupsRunning()) {
            String[] printerInfo = CUPSPrinter.getDefaultPrinter();
            defaultPrinter = printerInfo[0];
            psuri = printerInfo[1];
        } else {
            if (isMac() || isSysV()) {
                defaultPrinter = getDefaultPrinterNameSysV();
            } else {
                defaultPrinter = getDefaultPrinterNameBSD();
            }
        }
        if (defaultPrinter == null) {
            return null;
        }
        defaultPrintService = null;
        if (printServices != null) {
            for (int j=0; j<printServices.length; j++) {
                if (defaultPrinter.equals(getPrinterDestName(printServices[j]))) {
                    defaultPrintService = printServices[j];
                    break;
                }
            }
        }
        if (defaultPrintService == null) {
            if (CUPSPrinter.isCupsRunning()) {
                try {
                    PrintService defaultPS;
                    if ((psuri != null) && !psuri.startsWith("file")) {
                        defaultPS = new IPPPrintService(defaultPrinter,
                                                        psuri, true);
                    } else {
                        defaultPS = new IPPPrintService(defaultPrinter,
                                            new URL("http://"+
                                                    CUPSPrinter.getServer()+":"+
                                                    CUPSPrinter.getPort()+"/"+
                                                    defaultPrinter));
                    }
                    defaultPrintService = defaultPS;
                } catch (Exception e) {
                }
            } else {
                defaultPrintService = new UnixPrintService(defaultPrinter);
            }
        }

        return defaultPrintService;
    }

    public synchronized void
        getServicesInbackground(BackgroundLookupListener listener) {
        if (printServices != null) {
            listener.notifyServices(printServices);
        } else {
            if (lookupListeners == null) {
                lookupListeners = new Vector();
                lookupListeners.add(listener);
                Thread lookupThread = new Thread(this);
                lookupThread.start();
            } else {
                lookupListeners.add(listener);
            }
        }
    }

    /* This method isn't used in most cases because we rely on code in
     * javax.print.PrintServiceLookup. This is needed just for the cases
     * where those interfaces are by-passed.
     */
    private PrintService[] copyOf(PrintService[] inArr) {
        if (inArr == null || inArr.length == 0) {
            return inArr;
        } else {
            PrintService []outArr = new PrintService[inArr.length];
            System.arraycopy(inArr, 0, outArr, 0, inArr.length);
            return outArr;
        }
    }

    public void run() {
        PrintService[] services = getPrintServices();
        synchronized (this) {
            BackgroundLookupListener listener;
            for (int i=0; i<lookupListeners.size(); i++) {
                listener =
                    (BackgroundLookupListener)lookupListeners.elementAt(i);
                listener.notifyServices(copyOf(services));
            }
            lookupListeners = null;
        }
    }

    private String getDefaultPrinterNameBSD() {
        if (cmdIndex == UNINITIALIZED) {
            cmdIndex = getBSDCommandIndex();
        }
        String[] names = execCmd(lpcFirstCom[cmdIndex]);
        if (names == null || names.length == 0) {
            return null;
        }

        if ((cmdIndex==BSD_LPD_NG) &&
            (names[0].startsWith("missingprinter"))) {
            return null;
        }
        return names[0];
    }

    private PrintService getNamedPrinterNameBSD(String name) {
      if (cmdIndex == UNINITIALIZED) {
        cmdIndex = getBSDCommandIndex();
      }
      String command = "/usr/sbin/lpc status " + name + lpcNameCom[cmdIndex];
      String[] result = execCmd(command);

      if (result == null || !(result[0].equals(name))) {
          return null;
      }
      return new UnixPrintService(name);
    }

    private String[] getAllPrinterNamesBSD() {
        if (cmdIndex == UNINITIALIZED) {
            cmdIndex = getBSDCommandIndex();
        }
        String[] names = execCmd(lpcAllCom[cmdIndex]);
        if (names == null || names.length == 0) {
          return null;
        }
        return names;
    }

    static String getDefaultPrinterNameSysV() {
        String defaultPrinter = "lp";
        String command = "/usr/bin/lpstat -d";

        String [] names = execCmd(command);
        if (names == null || names.length == 0) {
            return defaultPrinter;
        } else {
            int index = names[0].indexOf(":");
            if (index == -1  || (names[0].length() <= index+1)) {
                return null;
            } else {
                String name = names[0].substring(index+1).trim();
                if (name.length() == 0) {
                    return null;
                } else {
                    return name;
                }
            }
        }
    }

    private PrintService getNamedPrinterNameSysV(String name) {

        String command = "/usr/bin/lpstat -v " + name;
        String []result = execCmd(command);

        if (result == null || result[0].indexOf("unknown printer") > 0) {
            return null;
        } else {
            return new UnixPrintService(name);
        }
    }

    private String[] getAllPrinterNamesSysV() {
        String defaultPrinter = "lp";
        String command = "/usr/bin/lpstat -v|/usr/bin/expand|/usr/bin/cut -f3 -d' ' |/usr/bin/cut -f1 -d':' | /usr/bin/sort";

        String [] names = execCmd(command);
        ArrayList printerNames = new ArrayList();
        for (int i=0; i < names.length; i++) {
            if (!names[i].equals("_default") &&
                !names[i].equals(defaultPrinter) &&
                !names[i].equals("")) {
                printerNames.add(names[i]);
            }
        }
        return (String[])printerNames.toArray(new String[printerNames.size()]);
    }

    static String[] execCmd(final String command) {
        ArrayList results = null;
        try {
            final String[] cmd = new String[3];
            if (isSysV()) {
                cmd[0] = "/usr/bin/sh";
                cmd[1] = "-c";
                cmd[2] = "env LC_ALL=C " + command;
            } else {
                cmd[0] = "/bin/sh";
                cmd[1] = "-c";
                cmd[2] = "LC_ALL=C " + command;
            }

            results = (ArrayList)AccessController.doPrivileged(
                new PrivilegedExceptionAction() {
                    public Object run() throws IOException {

                        Process proc;
                        BufferedReader bufferedReader = null;
                        File f = Files.createTempFile("prn","xc").toFile();
                        cmd[2] = cmd[2]+">"+f.getAbsolutePath();

                        proc = Runtime.getRuntime().exec(cmd);
                        try {
                            boolean done = false; // in case of interrupt.
                            while (!done) {
                                try {
                                    proc.waitFor();
                                    done = true;
                                } catch (InterruptedException e) {
                                }
                            }

                            if (proc.exitValue() == 0) {
                                FileReader reader = new FileReader(f);
                                bufferedReader = new BufferedReader(reader);
                                String line;
                                ArrayList results = new ArrayList();
                                while ((line = bufferedReader.readLine())
                                       != null) {
                                    results.add(line);
                                }
                                return results;
                            }
                        } finally {
                            f.delete();
                            // promptly close all streams.
                            if (bufferedReader != null) {
                                bufferedReader.close();
                            }
                            proc.getInputStream().close();
                            proc.getErrorStream().close();
                            proc.getOutputStream().close();
                        }
                        return null;
                    }
                });
        } catch (PrivilegedActionException e) {
        }
        if (results == null) {
            return new String[0];
        } else {
            return (String[])results.toArray(new String[results.size()]);
        }
    }

    private class PrinterChangeListener extends Thread {

        public void run() {
            int refreshSecs;
            while (true) {
                try {
                    refreshServices();
                } catch (Exception se) {
                    IPPPrintService.debug_println(debugPrefix+"Exception in refresh thread.");
                    break;
                }

                if ((printServices != null) &&
                    (printServices.length > minRefreshTime)) {
                    // compute new refresh time 1 printer = 1 sec
                    refreshSecs = printServices.length;
                } else {
                    refreshSecs = minRefreshTime;
                }
                try {
                    sleep(refreshSecs * 1000);
                } catch (InterruptedException e) {
                    break;
                }
            }
        }
    }
}

Other Java examples (source code examples)

Here is a short list of links related to this Java UnixPrintServiceLookup.java source code file:

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