Example usage for java.io RandomAccessFile getChannel

Introduction

In this page you can find the example usage for java.io RandomAccessFile getChannel.

Prototype

public final FileChannel getChannel() 

Source Link

Document

Returns the unique java.nio.channels.FileChannel FileChannel object associated with this file.

Usage

From source file:com.notifier.desktop.Main.java

private static boolean getExclusiveExecutionLock() throws IOException {
    File lockFile = new File(OperatingSystems.getWorkDirectory(), Application.ARTIFACT_ID + ".lock");
    Files.createParentDirs(lockFile);
    lockFile.createNewFile();//  w ww  .j  av  a2  s .co  m
    final RandomAccessFile randomAccessFile = new RandomAccessFile(lockFile, "rw");
    final FileChannel fileChannel = randomAccessFile.getChannel();
    final FileLock fileLock = fileChannel.tryLock();
    if (fileLock == null) {
        Closeables.closeQuietly(fileChannel);
        Closeables.closeQuietly(randomAccessFile);
        return false;
    }

    Runtime.getRuntime().addShutdownHook(new Thread() {
        @Override
        public void run() {
            try {
                fileLock.release();
            } catch (IOException e) {
                System.err.println("Error releasing file lock");
                e.printStackTrace(System.err);
            } finally {
                Closeables.closeQuietly(fileChannel);
                Closeables.closeQuietly(randomAccessFile);
            }
        }
    });
    return true;
}

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From source file:com.wabacus.util.FileLockTools.java

public static Object lock(String lockfile) {
    RandomAccessFile raf = null;
    FileChannel fc = null;//w  w w  . j av  a  2 s  .  c o m
    boolean islocked = true;
    try {
        raf = new RandomAccessFile(new File(lockfile), "rw");
        fc = raf.getChannel();
        FileLock fl = fc.tryLock();
        if (fl != null && fl.isValid()) {
            Map mapResources = new HashMap();
            mapResources.put("RAF", raf);
            mapResources.put("FC", fc);
            mapResources.put("FL", fl);
            return mapResources;
        } else {
            islocked = false;
            return null;
        }
    } catch (Exception e) {
        log.error("?" + lockfile + "?", e);
        return null;
    } finally {
        if (!islocked) {
            release(fc);
            release(raf);

        }
    }

}

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

public static FileLock tryLock(File file) {
    FileLock toReturn = null;//from  www  . j  a  v a 2  s  . co m

    try {
        RandomAccessFile raf = new RandomAccessFile(file, "rw");

        try {
            FileChannel channel = raf.getChannel();
            toReturn = channel.tryLock();
            raf.writeBytes("lock file for: " + ManagementFactory.getRuntimeMXBean().getName());
        } finally {
            if (toReturn == null)
                raf.close();
        }
    } catch (OverlappingFileLockException e) {
        toReturn = null;
    } catch (FileNotFoundException e) {
        toReturn = null;
    } catch (IOException e) {
        toReturn = null;
    }

    return toReturn;
}

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From source file:fusejext2.FuseJExt2.java

private static void setupBlockDevice() {
    try {//www .  j  a  va 2  s  .co  m
        RandomAccessFile blockDevFile = new RandomAccessFile(filename, "rw");
        blockDev = blockDevFile.getChannel();
    } catch (FileNotFoundException e) {
        System.out.println("Can't open block device or file " + filename);
        System.out.println(e.getMessage());
        System.exit(1);
    }
}

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From source file:org.uva.itast.blended.omr.pages.PDFPageImage.java

/**
 * @param filePath2//from   ww  w .  j av  a  2 s.  c o m
 * @throws IOException 
 */
public static PDFFile loadPDFFile(File inputpath) throws IOException {
    RandomAccessFile raf = new RandomAccessFile(inputpath, "r"); //se carga la imagen pdf para leerla
    FileChannel channel = raf.getChannel();
    ByteBuffer buf = channel.map(FileChannel.MapMode.READ_ONLY, 0, channel.size());
    PDFFile pdffile = new PDFFile(buf);
    return pdffile;
}

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From source file:com.amazonaws.services.s3.internal.FileLocks.java

/**
 * Acquires an exclusive lock on the specified file, creating the file as
 * necessary. Caller of this method is responsible to call the
 * {@link #unlock(File)} method to prevent release leakage.
 * /*from w  ww  . j  a va  2 s .co  m*/
 * @return true if the locking is successful; false otherwise.
 * 
 * @throws FileLockException if we failed to lock the file
 */
public static boolean lock(File file) {
    synchronized (lockedFiles) {
        if (lockedFiles.containsKey(file))
            return false; // already locked
    }
    FileLock lock = null;
    RandomAccessFile raf = null;
    try {
        // Note if the file does not already exist then an attempt will be
        // made to create it because of the use of "rw".
        raf = new RandomAccessFile(file, "rw");
        FileChannel channel = raf.getChannel();
        if (EXTERNAL_LOCK)
            lock = channel.lock();
    } catch (Exception e) {
        IOUtils.closeQuietly(raf, log);
        throw new FileLockException(e);
    }
    final boolean locked;
    synchronized (lockedFiles) {
        RandomAccessFile prev = lockedFiles.put(file, raf);
        if (prev == null) {
            locked = true;
        } else {
            // race condition: some other thread got locked it before this
            locked = false;
            lockedFiles.put(file, prev); // put it back
        }
    }
    if (locked) {
        if (log.isDebugEnabled())
            log.debug("Locked file " + file + " with " + lock);
    } else {
        IOUtils.closeQuietly(raf, log);
    }
    return locked;
}

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From source file:com.linkedin.pinot.perf.ForwardIndexReaderBenchmark.java

public static void singleValuedReadBenchMarkV2(File file, int numDocs, int numBits) throws Exception {
    boolean signed = false;
    boolean isMmap = false;
    long start, end;
    boolean fullScan = true;

    boolean batchRead = true;
    boolean singleRead = true;

    PinotDataBuffer heapBuffer = PinotDataBuffer.fromFile(file, ReadMode.heap, FileChannel.MapMode.READ_ONLY,
            "benchmarking");
    com.linkedin.pinot.core.io.reader.impl.v2.FixedBitSingleValueReader reader = new com.linkedin.pinot.core.io.reader.impl.v2.FixedBitSingleValueReader(
            heapBuffer, numDocs, numBits, signed);

    if (fullScan) {
        DescriptiveStatistics stats = new DescriptiveStatistics();
        ByteBuffer buffer = ByteBuffer.allocateDirect((int) file.length());
        RandomAccessFile raf = new RandomAccessFile(file, "r");
        raf.getChannel().read(buffer);
        raf.close();/*from  w w  w .j  a  va 2  s  .c  o m*/
        int[] input = new int[numBits];
        int[] output = new int[32];
        int numBatches = (numDocs + 31) / 32;
        for (int run = 0; run < MAX_RUNS; run++) {
            start = System.currentTimeMillis();
            for (int i = 0; i < numBatches; i++) {
                for (int j = 0; j < numBits; j++) {
                    input[j] = buffer.getInt(i * numBits * 4 + j * 4);
                }
                BitPacking.fastunpack(input, 0, output, 0, numBits);
            }
            end = System.currentTimeMillis();
            stats.addValue((end - start));
        }
        System.out.println(" v2 full scan stats for " + file.getName());
        System.out.println(
                stats.toString().replaceAll("\n", ", ") + " raw:" + Arrays.toString(stats.getValues()));
    }
    if (singleRead) {
        DescriptiveStatistics stats = new DescriptiveStatistics();
        // sequential read
        for (int run = 0; run < MAX_RUNS; run++) {
            start = System.currentTimeMillis();
            for (int i = 0; i < numDocs; i++) {
                int value = reader.getInt(i);
            }
            end = System.currentTimeMillis();
            stats.addValue((end - start));
        }
        System.out.println(" v2 sequential single read for " + file.getName());
        System.out.println(
                stats.toString().replaceAll("\n", ", ") + " raw:" + Arrays.toString(stats.getValues()));
    }
    if (batchRead) {
        DescriptiveStatistics stats = new DescriptiveStatistics();
        int batchSize = Math.min(5000, numDocs);
        int[] output = new int[batchSize];
        int[] rowIds = new int[batchSize];

        // sequential read
        for (int run = 0; run < MAX_RUNS; run++) {
            start = System.currentTimeMillis();
            int rowId = 0;
            while (rowId < numDocs) {
                int length = Math.min(batchSize, numDocs - rowId);
                for (int i = 0; i < length; i++) {
                    rowIds[i] = rowId + i;
                }
                reader.getIntBatch(rowIds, output, length);
                rowId = rowId + length;
            }
            end = System.currentTimeMillis();
            stats.addValue((end - start));
        }
        System.out.println("v2 sequential batch read stats for " + file.getName());
        System.out.println(
                stats.toString().replaceAll("\n", ", ") + " raw:" + Arrays.toString(stats.getValues()));
    }
    reader.close();

}

---

From source file:org.ednovo.gooru.application.util.GooruImageUtil.java

public static PDFFile getPDFFile(String pdfPath) {
    ByteBuffer buf;/*  w  ww.j  a  va  2  s  . co  m*/
    PDFFile pdfFile = null;
    try {
        File file = new File(pdfPath);
        @SuppressWarnings("resource")
        RandomAccessFile accessFile = new RandomAccessFile(file, "r");
        FileChannel channel = accessFile.getChannel();
        buf = channel.map(MapMode.READ_ONLY, 0, channel.size());
        pdfFile = new PDFFile(buf);
    } catch (Exception e) {
        LOGGER.error("getPDFFile: " + e);
    }
    return pdfFile;

}

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From source file:com.aliyun.oss.integrationtests.TestUtils.java

public static String genFixedLengthFile(long fixedLength) throws IOException {
    ensureDirExist(TestBase.UPLOAD_DIR);
    String filePath = TestBase.UPLOAD_DIR + System.currentTimeMillis();
    RandomAccessFile raf = new RandomAccessFile(filePath, "rw");
    FileChannel fc = raf.getChannel();

    MappedByteBuffer mbb = fc.map(MapMode.READ_WRITE, 0, fixedLength);
    try {/*from w  w  w .ja  v a  2  s .c  o  m*/
        for (int i = 0; i < fixedLength; i++) {
            mbb.put(pickupAlphabet());
        }
        return filePath;
    } finally {
        if (fc != null) {
            fc.close();
        }

        if (raf != null) {
            raf.close();
        }
    }
}

---

From source file:com.aliyun.oss.integrationtests.TestUtils.java

public static String genRandomLengthFile() throws IOException {
    ensureDirExist(TestBase.UPLOAD_DIR);
    String filePath = TestBase.UPLOAD_DIR + System.currentTimeMillis();
    RandomAccessFile raf = new RandomAccessFile(filePath, "rw");
    FileChannel fc = raf.getChannel();

    long fileLength = rand.nextInt(MAX_RANDOM_LENGTH);
    MappedByteBuffer mbb = fc.map(MapMode.READ_WRITE, 0, fileLength);
    try {//from   w ww .j a  va  2  s.  c  o m
        for (int i = 0; i < fileLength; i++) {
            mbb.put(pickupAlphabet());
        }
        return filePath;
    } finally {
        if (fc != null) {
            fc.close();
        }

        if (raf != null) {
            raf.close();
        }
    }
}

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