Example usage for java.nio.channels FileChannel tryLock

List of usage examples for java.nio.channels FileChannel tryLock

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Introduction

In this page you can find the example usage for java.nio.channels FileChannel tryLock.

Prototype

public final FileLock tryLock() throws IOException

Source Link

Document

Attempts to acquire an exclusive lock on this channel's file.

Usage

From source file:com.taobao.common.tfs.impl.GcWorker.java

private void doGc(SegmentInfoContainer segmentInfoContainer, File[] fileList) {
    for (File file : fileList) {
        if (file.length() == 0) {
            log.info("expired gc file is empty, unlink. " + file.getAbsolutePath());
            file.delete();//from   w  ww .  ja va  2  s. com
            continue;
        }

        String fileName = file.getAbsolutePath();
        log.info("do gc filename " + fileName);

        int serverIdIndex = fileName.lastIndexOf('!');
        if (serverIdIndex == -1) {
            log.error("file name is invalid, no server id: " + fileName);
            // unlink ?
            continue;
        }

        FileLock fileLock = null;
        try {
            FileChannel fileChannel = (new RandomAccessFile(file, "rw")).getChannel();
            fileLock = fileChannel.tryLock();
            if (fileLock == null) {
                log.warn("file: " + fileName + " is busy, maybe another gc worker is working over it");
                continue;
            }

            long serverId = Long.parseLong(fileName.substring(serverIdIndex + 1));
            segmentInfoContainer.loadFile(fileName);
            Collection<SegmentInfo> segmentInfos = segmentInfoContainer.getSegmentInfos();

            for (SegmentInfo segmentInfo : segmentInfos) {
                if (tfsManager.unlinkFile(segmentInfo.getBlockId(), segmentInfo.getFileId(), serverId)) {
                    log.info("gc success. blockId: " + segmentInfo.getBlockId() + " fileId: "
                            + segmentInfo.getFileId() + " serverId: " + serverId);
                } else {
                    log.error("gc fail. blockId: " + segmentInfo.getFileId() + " fileId: "
                            + segmentInfo.getFileId() + " serverId: " + serverId);
                }
            }
        } catch (Exception e) {
            log.warn("", e);
        } finally {
            try {
                if (fileLock != null) {
                    fileLock.release();
                }
                segmentInfoContainer.cleanUp();
                // delete anyway
                file.delete();
            } catch (Exception e) {
                log.warn("filelock realse fail.", e);
            }
        }
    }
}

From source file:com.sqlite.multiread.java

public void run() {
    newSqLiteAdapter.openToRead();//from  ww w . j  av  a 2 s  . co m
    long seconds1 = 0;
    long seconds2 = 0;
    Cursor cur = null;
    Transactions transactions = new Transactions();
    ArrayList<Long> array = new ArrayList<Long>();
    for (int i = 0; i < 10; i++) {
        seconds1 = System.currentTimeMillis();
        //cur = newSqLiteAdapter.queueAll("dammyTable", false, false, false,
        //         false, false, false, true, threadNum);
        seconds2 = System.currentTimeMillis();
        array.add(seconds2 - seconds1);
    }
    //   newSqLiteAdapter.close();
    FileOutputStream fos = null;
    try {
        byte[] data = new String("\nTotal time: " + transactions.average_time(array) / 8 + "ms  Thread Id: "
                + currentThread().getId() + " I Have read " + cur.getCount()).getBytes();

        File file = new File(Environment.getExternalStorageDirectory() + "/Aaa/", "threadsResults.txt");

        FileChannel channel = new RandomAccessFile(file, "rw").getChannel();

        FileLock lock = channel.lock();

        try {
            lock = channel.tryLock();
        } catch (OverlappingFileLockException e) {

        }

        fos = new FileOutputStream(file, true);
        fos.write(data);

        fos.flush();

        lock.release();
        channel.close();
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }

}

From source file:com.openddal.test.BaseTestCase.java

/**
 * Log an error message./*  w ww.  j av  a 2 s.co m*/
 *
 * @param s the message
 * @param e the exception
 */
public static void logError(String s, Throwable e) {
    if (e == null) {
        e = new Exception(s);
    }
    System.out.flush();
    System.err.println("ERROR: " + s + " " + e.toString() + " ------------------------------");
    e.printStackTrace();
    // synchronize on this class, because file locks are only visible to
    // other JVMs
    synchronized (BaseTestCase.class) {
        try {
            // lock
            FileChannel fc = FilePath.get("error.lock").open("rw");
            FileLock lock;
            while (true) {
                lock = fc.tryLock();
                if (lock != null) {
                    break;
                }
                Thread.sleep(10);
            }
            // append
            FileWriter fw = new FileWriter("error.txt", true);
            PrintWriter pw = new PrintWriter(fw);
            e.printStackTrace(pw);
            pw.close();
            fw.close();
            // unlock
            lock.release();
        } catch (Throwable t) {
            t.printStackTrace();
        }
    }
    System.err.flush();
}

From source file:cn.codepub.redis.directory.RedisLockFactory.java

@Override
public Lock obtainLock(@NonNull Directory dir, String lockName) throws IOException {
    if (!(dir instanceof RedisDirectory)) {
        throw new IllegalArgumentException("Expect argument of type [" + RedisDirectory.class.getName() + "]!");
    }// w  ww. j a va2  s.c  o m
    Path lockFile = lockFileDirectory.resolve(lockName);
    try {
        Files.createFile(lockFile);
        log.debug("Lock file path = {}", lockFile.toFile().getAbsolutePath());
    } catch (IOException ignore) {
        //ignore
        log.debug("Lock file already exists!");
    }
    final Path realPath = lockFile.toRealPath();
    final FileTime creationTime = Files.readAttributes(realPath, BasicFileAttributes.class).creationTime();
    if (LOCK_HELD.add(realPath.toString())) {
        FileChannel fileChannel = null;
        FileLock lock = null;
        try {
            fileChannel = FileChannel.open(realPath, StandardOpenOption.CREATE, StandardOpenOption.WRITE);
            lock = fileChannel.tryLock();
            if (lock != null) {
                return new RedisLock(lock, fileChannel, realPath, creationTime);
            } else {
                throw new LockObtainFailedException("Lock held by another program: " + realPath);
            }
        } finally {
            if (lock == null) {
                IOUtils.closeQuietly(fileChannel);
                clearLockHeld(realPath);
            }
        }
    } else {
        throw new LockObtainFailedException("Lock held by this virtual machine: " + realPath);
    }
}

From source file:net.yacy.yacy.java

/**
* Starts up the whole application. Sets up all datastructures and starts
* the main threads.//from w  ww. j av  a 2 s.  c  o m
*
* @param homePath Root-path where all information is to be found.
* @param startupFree free memory at startup time, to be used later for statistics
*/
private static void startup(final File dataHome, final File appHome, final long startupMemFree,
        final long startupMemTotal, final boolean gui) {
    String tmpdir = null;
    try {
        // start up
        System.out.println(copyright);
        System.out.println(hline);

        // ensure that there is a DATA directory, if not, create one and if that fails warn and die
        mkdirsIfNeseccary(dataHome);
        mkdirsIfNeseccary(appHome);
        File f = new File(dataHome, "DATA/");
        mkdirsIfNeseccary(f);
        if (!(f.exists())) {
            System.err.println("Error creating DATA-directory in " + dataHome.toString()
                    + " . Please check your write-permission for this folder. YaCy will now terminate.");
            System.exit(-1);
        }

        // set jvm tmpdir to a subdir for easy cleanup (as extensive use file.deleteonexit waists memory during long runs, as todelete files names are collected and never cleaned up during runtime)
        // keep this as earlier as possible, as any other class can use the "java.io.tmpdir" property, even the log manager, when the log file pattern uses "%t" as an alias for the tmp directory 
        try {
            tmpdir = java.nio.file.Files.createTempDirectory("yacy-tmp-").toString(); // creates sub dir in jvm's temp (see System.property "java.io.tempdir")
            System.setProperty("java.io.tmpdir", tmpdir);
        } catch (IOException ex) {
        }

        // setting up logging
        f = new File(dataHome, "DATA/LOG/");
        mkdirsIfNeseccary(f);
        f = new File(dataHome, "DATA/LOG/yacy.logging");
        final File f0 = new File(appHome, "defaults/yacy.logging");
        if (!f.exists() || f0.lastModified() > f.lastModified())
            try {
                Files.copy(f0, f);
            } catch (final IOException e) {
                System.out.println("could not copy yacy.logging");
            }
        try {
            ConcurrentLog.configureLogging(dataHome, new File(dataHome, "DATA/LOG/yacy.logging"));
        } catch (final IOException e) {
            System.out.println("could not find logging properties in homePath=" + dataHome);
            ConcurrentLog.logException(e);
        }
        ConcurrentLog.config("STARTUP", "YaCy version: " + yacyBuildProperties.getVersion() + "/"
                + yacyBuildProperties.getSVNRevision());
        ConcurrentLog.config("STARTUP",
                "Java version: " + System.getProperty("java.version", "no-java-version"));
        ConcurrentLog.config("STARTUP", "Operation system: " + System.getProperty("os.name", "unknown"));
        ConcurrentLog.config("STARTUP", "Application root-path: " + appHome);
        ConcurrentLog.config("STARTUP", "Data root-path: " + dataHome);
        ConcurrentLog.config("STARTUP", "Time zone: UTC" + GenericFormatter.UTCDiffString() + "; UTC+0000 is "
                + System.currentTimeMillis());
        ConcurrentLog.config("STARTUP", "Maximum file system path length: " + OS.maxPathLength);

        f = new File(dataHome, "DATA/yacy.running");
        final String conf = "DATA/SETTINGS/yacy.conf".replace("/", File.separator);
        if (!f.createNewFile())
            ConcurrentLog.severe("STARTUP", "WARNING: the file " + f + " can not be created!");
        try {
            new FileOutputStream(f).write(Integer.toString(OS.getPID()).getBytes());
        } catch (final Exception e) {
        } // write PID
        f.deleteOnExit();
        FileChannel channel = null;
        FileLock lock = null;
        try {
            channel = new RandomAccessFile(f, "rw").getChannel();
            lock = channel.tryLock(); // lock yacy.running
        } catch (final Exception e) {
        }

        try {
            sb = new Switchboard(dataHome, appHome, "defaults/yacy.init".replace("/", File.separator), conf);
        } catch (final RuntimeException e) {
            ConcurrentLog.severe("STARTUP", "YaCy cannot start: " + e.getMessage(), e);
            System.exit(-1);
        }
        //sbSync.V(); // signal that the sb reference was set

        // switch the memory strategy
        MemoryControl.setStandardStrategy(sb.getConfigBool("memory.standardStrategy", true));

        // save information about available memory at startup time
        sb.setConfig("memoryFreeAfterStartup", startupMemFree);
        sb.setConfig("memoryTotalAfterStartup", startupMemTotal);

        // start gui if wanted
        if (gui)
            YaCyApp.start("localhost", sb.getLocalPort());

        // hardcoded, forced, temporary value-migration
        sb.setConfig("htTemplatePath", "htroot/env/templates");

        double oldVer;
        try {
            String tmpversion = sb.getConfig(Seed.VERSION, "");
            if (tmpversion.isEmpty()) { // before 1.83009737 only the svnRevision nr was in config (like 9737)
                tmpversion = yacyBuildProperties.getVersion();
                int oldRev = Integer.parseInt(sb.getConfig("svnRevision", "0"));
                if (oldRev > 1) {
                    oldVer = Double.parseDouble(tmpversion) + oldRev / 100000000.0;
                } else {
                    oldVer = Double.parseDouble(yacyBuildProperties.getLongVersion()); // failsafe (assume current version = no migration)
                }
            } else {
                oldVer = Double.parseDouble(tmpversion);
            }
        } catch (final NumberFormatException e) {
            oldVer = 0.0d;
        }
        final double newRev = Double.parseDouble(yacyBuildProperties.getLongVersion());
        sb.setConfig(Seed.VERSION, yacyBuildProperties.getLongVersion());
        sb.setConfig("applicationRoot", appHome.toString());
        sb.setConfig("dataRoot", dataHome.toString());

        // create some directories
        final File htRootPath = new File(appHome,
                sb.getConfig(SwitchboardConstants.HTROOT_PATH, SwitchboardConstants.HTROOT_PATH_DEFAULT));
        mkdirIfNeseccary(htRootPath);
        htDocsPath = sb.getDataPath(SwitchboardConstants.HTDOCS_PATH, SwitchboardConstants.HTDOCS_PATH_DEFAULT);
        mkdirIfNeseccary(htDocsPath);
        //final File htTemplatePath = new File(homePath, sb.getConfig("htTemplatePath","htdocs"));

        // copy the donate iframe (better to copy this once here instead of doing this in an actual iframe in the search result)
        importDonationIFrame(sb, htDocsPath);

        // create default notifier picture
        File notifierFile = new File(htDocsPath, "notifier.gif");
        if (!notifierFile.exists())
            try {
                Files.copy(new File(htRootPath, "env/grafics/empty.gif"), notifierFile);
            } catch (final IOException e) {
            }

        final File htdocsReadme = new File(htDocsPath, "readme.txt");
        if (!(htdocsReadme.exists()))
            try {
                FileUtils.copy(("This is your root directory for individual Web Content\r\n" + "\r\n"
                        + "Please place your html files into the www subdirectory.\r\n"
                        + "The URL of that path is either\r\n" + "http://www.<your-peer-name>.yacy    or\r\n"
                        + "http://<your-ip>:<your-port>/www\r\n" + "\r\n"
                        + "Other subdirectories may be created; they map to corresponding sub-domains.\r\n"
                        + "This directory shares it's content with the applications htroot path, so you\r\n"
                        + "may access your yacy search page with\r\n" + "http://<your-peer-name>.yacy/\r\n"
                        + "\r\n").getBytes(), htdocsReadme);
            } catch (final IOException e) {
                System.out.println("Error creating htdocs readme: " + e.getMessage());
            }

        shareDefaultPath = new File(htDocsPath, "share");
        mkdirIfNeseccary(shareDefaultPath);
        shareDumpDefaultPath = new File(shareDefaultPath, "dump");
        mkdirIfNeseccary(shareDumpDefaultPath);

        migration.migrate(sb, oldVer, newRev);

        // delete old release files
        final int deleteOldDownloadsAfterDays = (int) sb.getConfigLong("update.deleteOld", 30);
        yacyRelease.deleteOldDownloads(sb.releasePath, deleteOldDownloadsAfterDays);

        // set user-agent
        HTTPClient.setDefaultUserAgent(ClientIdentification.yacyInternetCrawlerAgent.userAgent);

        // start main threads
        final int port = sb.getLocalPort();
        try {
            // start http server
            YaCyHttpServer httpServer;
            httpServer = new Jetty9HttpServerImpl(port);
            httpServer.startupServer();
            sb.setHttpServer(httpServer);
            // TODO: this has no effect on Jetty (but needed to reflect configured value and limit is still used)
            ConnectionInfo.setServerMaxcount(sb.getConfigInt("connectionsMax", ConnectionInfo.getMaxcount()));

            ConcurrentLog.info("STARTUP", httpServer.getVersion());

            // open the browser window
            final boolean browserPopUpTrigger = sb
                    .getConfig(SwitchboardConstants.BROWSER_POP_UP_TRIGGER, "true").equals("true");
            if (browserPopUpTrigger)
                try {
                    final String browserPopUpPage = sb.getConfig(SwitchboardConstants.BROWSER_POP_UP_PAGE,
                            "ConfigBasic.html");
                    //boolean properPW = (sb.getConfig(SwitchboardConstants.ADMIN_ACCOUNT, "").isEmpty()) && (sb.getConfig(httpd.ADMIN_ACCOUNT_B64MD5, "").length() > 0);
                    //if (!properPW) browserPopUpPage = "ConfigBasic.html";
                    /* YaCy main startup process must not hang because browser opening is long or fails. 
                     * Let's open try opening the browser in a separate thread */
                    new Thread("Browser opening") {
                        @Override
                        public void run() {
                            Browser.openBrowser(("http://localhost:" + port) + "/" + browserPopUpPage);
                        }
                    }.start();
                    // Browser.openBrowser((server.withSSL()?"https":"http") + "://localhost:" + serverCore.getPortNr(port) + "/" + browserPopUpPage);
                } catch (final Throwable e) {
                    // cannot open browser. This may be normal in headless environments
                    //Log.logException(e);
                }

            // enable browser popup, http server is ready now
            sb.tray.setReady();

            //regenerate Locales from Translationlist, if needed
            final File locale_source = sb.getAppPath("locale.source", "locales");
            final String lang = sb.getConfig("locale.language", "");
            // on lang=browser all active translation should be checked (because any could be requested by client)
            List<String> langlist;
            if (lang.endsWith("browser"))
                langlist = Translator.activeTranslations(); // get all translated languages
            else {
                langlist = new ArrayList<String>();
                langlist.add(lang);
            }
            for (String tmplang : langlist) {
                if (!tmplang.equals("") && !tmplang.equals("default") && !tmplang.equals("browser")) { //locale is used
                    String currentRev = null;
                    BufferedReader br = null;
                    try {
                        br = new BufferedReader(new InputStreamReader(new FileInputStream(
                                new File(sb.getDataPath("locale.translated_html", "DATA/LOCALE/htroot"),
                                        tmplang + "/version"))));
                        currentRev = br.readLine(); // may return null
                    } catch (final IOException e) {
                        //Error
                    } finally {
                        try {
                            br.close();
                        } catch (IOException ioe) {
                            ConcurrentLog.warn("STARTUP", "Could not close " + tmplang + " version file");
                        }
                    }

                    if (currentRev == null || !currentRev.equals(sb.getConfig(Seed.VERSION, ""))) {
                        try { //is this another version?!
                            final File sourceDir = new File(sb.getConfig(SwitchboardConstants.HTROOT_PATH,
                                    SwitchboardConstants.HTROOT_PATH_DEFAULT));
                            final File destDir = new File(
                                    sb.getDataPath("locale.translated_html", "DATA/LOCALE/htroot"), tmplang);
                            if (new TranslatorXliff().translateFilesRecursive(sourceDir, destDir,
                                    new File(locale_source, tmplang + ".lng"), "html,template,inc", "locale")) { //translate it
                                //write the new Versionnumber
                                final BufferedWriter bw = new BufferedWriter(
                                        new PrintWriter(new FileWriter(new File(destDir, "version"))));
                                bw.write(sb.getConfig(Seed.VERSION, "Error getting Version"));
                                bw.close();
                            }
                        } catch (final IOException e) {
                        }
                    }
                }
            }
            // initialize number formatter with this locale
            if (!lang.equals("browser")) // "default" is handled by .setLocale()
                Formatter.setLocale(lang);

            // registering shutdown hook
            ConcurrentLog.config("STARTUP", "Registering Shutdown Hook");
            final Runtime run = Runtime.getRuntime();
            run.addShutdownHook(new shutdownHookThread(sb, shutdownSemaphore));

            // save information about available memory after all initializations
            //try {
            sb.setConfig("memoryFreeAfterInitBGC", MemoryControl.free());
            sb.setConfig("memoryTotalAfterInitBGC", MemoryControl.total());
            System.gc();
            sb.setConfig("memoryFreeAfterInitAGC", MemoryControl.free());
            sb.setConfig("memoryTotalAfterInitAGC", MemoryControl.total());
            //} catch (final ConcurrentModificationException e) {}

            // wait for server shutdown
            try {
                sb.waitForShutdown();
            } catch (final Exception e) {
                ConcurrentLog.severe("MAIN CONTROL LOOP", "PANIC: " + e.getMessage(), e);
            }
            // shut down
            Array.terminate();
            ConcurrentLog.config("SHUTDOWN", "caught termination signal");
            httpServer.stop();

            ConcurrentLog.config("SHUTDOWN", "server has terminated");
            sb.close();
        } catch (final Exception e) {
            ConcurrentLog.severe("STARTUP", "Unexpected Error: " + e.getClass().getName(), e);
            //System.exit(1);
        }
        if (lock != null)
            lock.release();
        if (channel != null)
            channel.close();
    } catch (final Exception ee) {
        ConcurrentLog.severe("STARTUP", "FATAL ERROR: " + ee.getMessage(), ee);
    } finally {
    }

    if (tmpdir != null)
        FileUtils.deletedelete(new File(tmpdir)); // clean up temp dir (set at startup as subdir of system.propery "java.io.tmpdir")

    ConcurrentLog.config("SHUTDOWN", "goodbye. (this is the last line)");
    ConcurrentLog.shutdown();
    shutdownSemaphore.release(1000);
    try {
        System.exit(0);
    } catch (final Exception e) {
    } // was once stopped by de.anomic.net.ftpc$sm.checkExit(ftpc.java:1790)
}

From source file:com.ephesoft.dcma.util.FileUtils.java

/**
 * API to take read write lock on the folder represented by the given folder path.
 * /*from  w  w  w . ja  v a  2  s .c  o  m*/
 * @param folderPath {@link String}
 * @return true if lock is successfully acquired, else false
 */
public static boolean lockFolder(String folderPath) {
    String lockFileName = folderPath + File.separator + "_lock";
    boolean isLockAcquired = true;
    try {
        File lockFile = new File(lockFileName);
        FileChannel fileChannel = new RandomAccessFile(lockFile, "rw").getChannel();

        FileLock lock = fileChannel.lock();

        try {
            if (lock == null) {
                lock = fileChannel.tryLock();
            }
        } catch (OverlappingFileLockException e) {
            LOGGER.trace("File is already locked in this thread or virtual machine");
        }
        if (lock == null) {
            LOGGER.trace("File is already locked in this thread or virtual machine");
        }

    } catch (Exception e) {
        LOGGER.error("Unable to aquire lock on file : " + lockFileName, e);
        isLockAcquired = false;
    }
    return isLockAcquired;
}

From source file:com.espirit.moddev.examples.uxbridge.newsdrilldown.jpa.NewsHandler.java

/**
 * Deletes a newsdrilldown from the db.//from   ww w .  jav  a  2  s . co m
 *
 * @param entity The newsdrilldown to delete
 */
public void delete(UXBEntity entity) throws Exception {

    EntityManager em = null;
    EntityTransaction tx = null;
    try {

        em = emf.createEntityManager();
        tx = em.getTransaction();
        tx.begin();

        Query query = em.createQuery(new StringBuilder()
                .append("FROM news x WHERE x.fs_id = :fs_id AND x.language = :language").toString());
        query.setParameter("fs_id", Long.parseLong(entity.getUuid()));
        query.setParameter("language", entity.getLanguage());

        if (!query.getResultList().isEmpty()) {
            News art = (News) query.getSingleResult();
            // delete file from filesystem
            URL url = new URL(art.getUrl());
            File file = new File(webpath + url.getPath());
            if (file.exists()) {
                // Try acquiring the lock without blocking. This method returns
                // null or throws an exception if the file is already locked.
                try {
                    FileChannel channel = new RandomAccessFile(file, "rw").getChannel();
                    // Try to lock the file
                    FileLock lock = channel.tryLock();
                    // Delete the file
                    file.delete();
                    // Release the lock
                    lock.release();
                    lock.channel().close();
                } catch (OverlappingFileLockException e) {
                    logger.info("File is already locked in this thread or virtual machine");
                } catch (MalformedURLException e) {
                    logger.info("wrong url", e);
                }
            }
            // remove article from content repository

            em.remove(art);
        }
        tx.commit();
    } catch (Exception e) {
        if (tx != null) {
            tx.setRollbackOnly();
        }
        throw e;
    } finally {
        if (tx != null && tx.isActive()) {
            if (tx.getRollbackOnly()) {
                tx.rollback();
            }
        }
        if (em != null) {
            em.close();
        }
    }
}

From source file:com.clustercontrol.agent.job.PublicKeyThread.java

/**
 * ?Authorized_key????<BR>//from w ww.  ja v  a  2 s .c  o m
 * 
 * @param publicKey
 * @return
 */
private synchronized boolean addKey(String publicKey) {
    m_log.debug("add key start");

    if (SKIP_KEYFILE_UPDATE) {
        m_log.info("skipped appending publicKey");
        return true;
    }

    //???
    String fileName = AgentProperties.getProperty(execUser.toLowerCase() + AUTHORIZED_KEY_PATH);

    m_log.debug("faileName" + fileName);
    if (fileName == null || fileName.length() == 0)
        return false;

    //File?
    File fi = new File(fileName);

    RandomAccessFile randomAccessFile = null;
    FileChannel channel = null;
    FileLock lock = null;
    boolean add = false;
    try {
        //RandomAccessFile?
        randomAccessFile = new RandomAccessFile(fi, "rw");
        //FileChannel?
        channel = randomAccessFile.getChannel();

        // 
        for (int i = 0; i < (FILELOCK_TIMEOUT / FILELOCK_WAIT); i++) {
            if (null != (lock = channel.tryLock())) {
                break;
            }
            m_log.info("waiting for locked file... [" + (i + 1) + "/" + (FILELOCK_TIMEOUT / FILELOCK_WAIT)
                    + " : " + fileName + "]");
            Thread.sleep(FILELOCK_WAIT);
        }
        if (null == lock) {
            m_log.warn("file locking timeout.");
            return false;
        }

        // (?)
        synchronized (authKeyLock) {
            //??
            channel.position(channel.size());

            //?
            String writeData = "\n" + publicKey;
            // 
            m_log.debug("add key : " + writeData);

            //?????
            ByteBuffer buffer = ByteBuffer.allocate(512);

            //???
            buffer.clear();
            buffer.put(writeData.getBytes());
            buffer.flip();
            channel.write(buffer);
        }

        add = true;
    } catch (Exception e) {
        m_log.error(e);
    } finally {
        try {
            if (channel != null) {
                channel.close();
            }
            if (randomAccessFile != null) {
                randomAccessFile.close();
            }
            if (lock != null) {
                //
                lock.release();
            }
        } catch (Exception e) {
        }
    }

    return add;
}

From source file:com.clustercontrol.agent.job.PublicKeyThread.java

/**
 *  ?Authorized_key????<BR>/*from w  w  w.ja va  2 s . co  m*/
 * 
 * @param publicKey
 * @return true : ?false:
 */
private synchronized boolean deleteKey(String publicKey) {
    m_log.debug("delete key start");

    if (SKIP_KEYFILE_UPDATE) {
        m_log.info("skipped deleting publicKey");
        return true;
    }

    Charset charset = Charset.forName("UTF-8");
    CharsetEncoder encoder = charset.newEncoder();
    CharsetDecoder decoder = charset.newDecoder();

    //???
    String fileName = AgentProperties.getProperty(execUser.toLowerCase() + AUTHORIZED_KEY_PATH);
    if (fileName == null || fileName.length() == 0)
        return false;

    //File?
    File fi = new File(fileName);

    RandomAccessFile randomAccessFile = null;
    FileChannel channel = null;
    FileLock lock = null;
    boolean delete = false;
    try {
        //RandomAccessFile?
        randomAccessFile = new RandomAccessFile(fi, "rw");
        //FileChannel?
        channel = randomAccessFile.getChannel();

        // 
        for (int i = 0; i < (FILELOCK_TIMEOUT / FILELOCK_WAIT); i++) {
            if (null != (lock = channel.tryLock())) {
                break;
            }
            m_log.info("waiting for locked file... [" + (i + 1) + "/" + (FILELOCK_TIMEOUT / FILELOCK_WAIT)
                    + " : " + fileName + "]");
            Thread.sleep(FILELOCK_WAIT);
        }
        if (null == lock) {
            m_log.warn("file locking timeout.");
            return false;
        }

        // (?)
        synchronized (authKeyLock) {
            //??
            ByteBuffer buffer = ByteBuffer.allocate((int) channel.size());

            //??
            channel.read(buffer);

            // ???????????0?
            buffer.flip();

            //??
            String contents = decoder.decode(buffer).toString();

            // ?
            m_log.debug("contents " + contents.length() + " : " + contents);

            //??
            List<String> keyCheck = new ArrayList<String>();
            StringTokenizer tokenizer = new StringTokenizer(contents, "\n");
            while (tokenizer.hasMoreTokens()) {
                keyCheck.add(tokenizer.nextToken());
            }

            //??????
            int s = keyCheck.lastIndexOf(publicKey);
            if (s != -1) {
                // ?
                m_log.debug("remobe key : " + keyCheck.get(s));
                keyCheck.remove(s);
            }

            //?????
            encoder.reset();
            buffer.clear();

            int i;
            if (keyCheck.size() > 0) {
                for (i = 0; i < keyCheck.size() - 1; i++) {
                    encoder.encode(CharBuffer.wrap(keyCheck.get(i) + "\n"), buffer, false);
                }
                encoder.encode(CharBuffer.wrap(keyCheck.get(i)), buffer, true);
            }

            //???
            buffer.flip();
            channel.truncate(0);
            channel.position(0);
            channel.write(buffer);
        }

        delete = true;
    } catch (IOException e) {
        m_log.error(e.getMessage(), e);
    } catch (RuntimeException e) {
        m_log.error(e.getMessage(), e);
    } catch (InterruptedException e) {
        m_log.error(e.getMessage(), e);
    } finally {
        try {
            if (channel != null) {
                channel.close();
            }
            if (randomAccessFile != null) {
                randomAccessFile.close();
            }
            //?
            if (lock != null) {
                lock.release();
            }
        } catch (Exception e) {
        }
    }

    return delete;
}

From source file:com.mindquarry.desktop.client.MindClient.java

private void createLock() {
    File f = new File(LOCK_FILE);

    try {// w w w.j a v  a  2  s  .  co  m
        if (!f.exists()) {
            f.createNewFile();
        }
    } catch (IOException e) {
        log.error("Cannot create lock file '" + f.getAbsolutePath() + "'", e); //$NON-NLS-1$
    }

    // this is the recommended way to implement locking, it doesn't leave
    // a lock file, not even if the app crashes:
    FileChannel fileChannel;
    try {
        fileChannel = (new FileOutputStream(f)).getChannel();
        fileLock = fileChannel.tryLock();
        if (fileLock == null) {
            MessageDialog dlg = new MessageDialog(getShell(),
                    I18N.getString("Mindquarry Client already running"), null,
                    I18N.getString("The Mindquarry Desktop Client seems to be running "
                            + "already. Only one instance of the Desktop Client can be "
                            + "running at a time. If you are sure that the Desktop Client "
                            + "isn't running, select 'Start anyway'."),
                    MessageDialog.ERROR,
                    new String[] { I18N.getString("Exit"), I18N.getString("Start anyway") }, 0);
            int result = dlg.open();
            if (result == 0) {
                System.exit(1);
            } else {
                log.warn("Starting despite lock file"); //$NON-NLS-1$
            }
        } else {
            log.info("Aquired lock: " + fileLock);
        }
    } catch (IOException e) {
        log.error("Cannot create lock on lock file '" + f.getAbsolutePath(), e);
    }
    // Note: no need to delete the lock, the JVM will care about that
}