Example usage for java.nio.channels FileChannel force

Introduction

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

Prototype

public abstract void force(boolean metaData) throws IOException;

Source Link

Document

Forces any updates to this channel's file to be written to the storage device that contains it.

Usage

From source file:Lock.java

public static void main(String args[]) throws IOException, InterruptedException {
    RandomAccessFile file = null; // The file we'll lock
    FileChannel f = null; // The channel to the file
    FileLock lock = null; // The lock object we hold

    try { // The finally clause closes the channel and releases the lock
        // We use a temporary file as the lock file.
        String tmpdir = System.getProperty("java.io.tmpdir");
        String filename = Lock.class.getName() + ".lock";
        File lockfile = new File(tmpdir, filename);

        // Create a FileChannel that can read and write that file.
        // Note that we rely on the java.io package to open the file,
        // in read/write mode, and then just get a channel from it.
        // This will create the file if it doesn't exit. We'll arrange
        // for it to be deleted below, if we succeed in locking it.
        file = new RandomAccessFile(lockfile, "rw");
        f = file.getChannel();// w  w  w. j  a  v a 2  s .  c  o m

        // Try to get an exclusive lock on the file.
        // This method will return a lock or null, but will not block.
        // See also FileChannel.lock() for a blocking variant.
        lock = f.tryLock();

        if (lock != null) {
            // We obtained the lock, so arrange to delete the file when
            // we're done, and then write the approximate time at which
            // we'll relinquish the lock into the file.
            lockfile.deleteOnExit(); // Just a temporary file

            // First, we need a buffer to hold the timestamp
            ByteBuffer bytes = ByteBuffer.allocate(8); // a long is 8 bytes

            // Put the time in the buffer and flip to prepare for writing
            // Note that many Buffer methods can be "chained" like this.
            bytes.putLong(System.currentTimeMillis() + 10000).flip();

            f.write(bytes); // Write the buffer contents to the channel
            f.force(false); // Force them out to the disk
        } else {
            // We didn't get the lock, which means another instance is
            // running. First, let the user know this.
            System.out.println("Another instance is already running");

            // Next, we attempt to read the file to figure out how much
            // longer the other instance will be running. Since we don't
            // have a lock, the read may fail or return inconsistent data.
            try {
                ByteBuffer bytes = ByteBuffer.allocate(8);
                f.read(bytes); // Read 8 bytes from the file
                bytes.flip(); // Flip buffer before extracting bytes
                long exittime = bytes.getLong(); // Read bytes as a long
                // Figure out how long that time is from now and round
                // it to the nearest second.
                long secs = (exittime - System.currentTimeMillis() + 500) / 1000;
                // And tell the user about it.
                System.out.println("Try again in about " + secs + " seconds");
            } catch (IOException e) {
                // This probably means that locking is enforced by the OS
                // and we were prevented from reading the file.
            }

            // This is an abnormal exit, so set an exit code.
            System.exit(1);
        }

        // Simulate a real application by sleeping for 10 seconds.
        System.out.println("Starting...");
        Thread.sleep(10000);
        System.out.println("Exiting.");
    } finally {
        // Always release the lock and close the file
        // Closing the RandomAccessFile also closes its FileChannel.
        if (lock != null && lock.isValid())
            lock.release();
        if (file != null)
            file.close();
    }
}

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From source file:Main.java

private static void writeFileFromBytes(final File file, final byte[] bytes) {
    FileChannel fc = null;
    try {//from   w w w .j  a  v a2s  .  c  o m
        fc = new FileOutputStream(file, false).getChannel();
        fc.write(ByteBuffer.wrap(bytes));
        fc.force(true);
    } catch (IOException e) {
        e.printStackTrace();
    } finally {
        try {
            if (fc != null) {
                fc.close();
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

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From source file:Main.java

public static void toFile(ByteBuffer buffer, File file) throws IOException {
    RandomAccessFile raf = null;//from   ww  w. ja  va 2 s. c o  m
    FileChannel channel = null;
    try {
        raf = new RandomAccessFile(file, "rw");
        channel = raf.getChannel();
        channel.write(buffer);
        channel.force(false /*metadata*/);
        channel.close();
        raf.close();
    } finally {
        if (channel != null) {
            try {
                channel.close();
            } catch (IOException e) {
                // Ignored.
            }
        }
        if (raf != null) {
            try {
                raf.close();
            } catch (IOException e) {
                // Ignored.
            }
        }
    }
}

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From source file:com.github.neoio.nio.util.NIOUtils.java

public static void resetFileChannelForReading(FileChannel channel) throws NetIOException {
    try {//  w  ww  . j a  va2 s.  com
        channel.force(true);
        channel.position(0);
    } catch (IOException e) {
        throw new NetIOException(e);
    }
}

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From source file:cd.education.data.collector.android.utilities.FileUtils.java

private static String actualCopy(File sourceFile, File destFile) {
    FileInputStream fileInputStream = null;
    FileOutputStream fileOutputStream = null;
    FileChannel src = null;/*from   w  w w .  jav a 2  s .c o m*/
    FileChannel dst = null;
    try {
        fileInputStream = new FileInputStream(sourceFile);
        src = fileInputStream.getChannel();
        fileOutputStream = new FileOutputStream(destFile);
        dst = fileOutputStream.getChannel();
        dst.transferFrom(src, 0, src.size());
        dst.force(true);
        return null;
    } catch (FileNotFoundException e) {
        Log.e(t, "FileNotFoundException while copying file", e);
        return e.getMessage();
    } catch (IOException e) {
        Log.e(t, "IOException while copying file", e);
        return e.getMessage();
    } catch (Exception e) {
        Log.e(t, "Exception while copying file", e);
        return e.getMessage();
    } finally {
        IOUtils.closeQuietly(fileInputStream);
        IOUtils.closeQuietly(fileOutputStream);
        IOUtils.closeQuietly(src);
        IOUtils.closeQuietly(dst);
    }
}

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From source file:Main.java

public static boolean fileCopy(File srcFile, File dstFile) {
    int length = 1048891;
    FileChannel inC = null;// w  w  w. j av  a 2  s.  c  om
    FileChannel outC = null;
    try {
        FileInputStream in = new FileInputStream(srcFile);
        FileOutputStream out = new FileOutputStream(dstFile);
        inC = in.getChannel();
        outC = out.getChannel();
        ByteBuffer b = null;
        while (inC.position() < inC.size()) {
            if ((inC.size() - inC.position()) < length) {
                length = (int) (inC.size() - inC.position());
            } else {
                length = 1048891;
            }
            b = ByteBuffer.allocateDirect(length);
            inC.read(b);
            b.flip();
            outC.write(b);
            outC.force(false);
        }

        return true;
    } catch (IOException e) {
        e.printStackTrace();
        return false;
    } finally {
        try {
            if (inC != null && inC.isOpen()) {
                inC.close();
            }
            if (outC != null && outC.isOpen()) {
                outC.close();
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

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From source file:com.imaginea.kodebeagle.base.util.Utils.java

public void forceWrite(final String contents, final File file) throws IOException {
    try (FileOutputStream s = new FileOutputStream(file.getAbsolutePath(), false)) {
        s.write(contents.getBytes(StandardCharsets.UTF_8.name()));
        FileChannel c = s.getChannel();
        c.force(true);
        s.getFD().sync();/* ww  w . j  a v a2s .c  o  m*/
        c.close();
        s.close();
    }
}

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From source file:edu.rit.flick.genetics.FastFileDeflator.java

@SuppressWarnings("resource")
protected void removeUnusedBufferSpace(final String tmpOutputDirectory)
        throws IOException, InterruptedException {
    final long actualDataHcfFileSize = datahcf.position();
    final long actualNFileSize = nfile.position();

    fastIn.close();//  w ww.j a  v a  2s . c om
    datahcf.close();
    headerfile.close();
    nfile.close();
    iupacfile.close();
    tailfile.close();
    metafile.close();

    fastIn = null;
    datahcf = null;
    nfile = null;

    // Give the last method a moment to garbage collect
    // System.gc();
    // Thread.sleep( 1000 );

    final File dataFile = new File(tmpOutputDirectory + SEQUENCE_DATA_FILE);
    final File nFile = new File(tmpOutputDirectory + N_FILE);

    // Remove unused buffer space
    FileChannel fc = new FileOutputStream(dataFile, true).getChannel();
    fc.force(true);
    fc.truncate(actualDataHcfFileSize).close();

    fc = new FileOutputStream(nFile, true).getChannel();
    fc.force(true);
    fc.truncate(actualNFileSize).close();
}

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From source file:com.yobidrive.diskmap.needles.NeedleManager.java

public void close() {
    Enumeration<FileChannel> channels = channelMap.elements();
    while (channels.hasMoreElements()) {
        FileChannel fc = channels.nextElement();
        try {//from   w w  w . ja  va2s .  c om
            fc.force(true);
            fc.close();
        } catch (Throwable th) {
            logger.error("Error closing needle channel", th);
        }
    }
}

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From source file:com.yobidrive.diskmap.needles.NeedleManager.java

public void syncAll() {
    Enumeration<FileChannel> channels = channelMap.elements();
    while (channels.hasMoreElements()) {
        FileChannel fc = channels.nextElement();
        try {//  w w  w . java 2s .c  o m
            fc.force(true);
        } catch (Throwable th) {
            logger.error("Error synching needle channel", th);
        }
    }
    // logger.info(needleHeaderReadCache.stats().toString()) ;
}

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