Examples with FileLock java.nio.channels.FileLock used on opensource projects

Example 51 with FileLock

use of java.nio.channels.FileLock in project Chronicle-Queue by OpenHFT.

the class SingleTableStore method doWithExclusiveLock.

/**
 * {@inheritDoc}
 */
@Override
public <R> R doWithExclusiveLock(Function<TableStore, ? extends R> code) {
    final long timeoutAt = System.currentTimeMillis() + 2 * timeoutMS;
    boolean warnedOnFailure = false;
    try (final FileChannel channel = FileChannel.open(file().toPath(), StandardOpenOption.WRITE)) {
        while (System.currentTimeMillis() < timeoutAt) {
            try {
                FileLock fileLock = channel.tryLock();
                if (fileLock != null) {
                    return code.apply(this);
                }
            } catch (IOException | OverlappingFileLockException e) {
                // failed to acquire the lock, wait until other operation completes
                if (!warnedOnFailure) {
                    Jvm.debug().on(getClass(), "Failed to acquire a lock on the table store file. Retrying");
                    warnedOnFailure = true;
                }
            }
            Jvm.pause(50L);
        }
    } catch (IOException e) {
        throw new IllegalStateException("Couldn't open table store file for writing", e);
    }
    throw new IllegalStateException("Unable to claim exclusive lock on file " + file());
}

Example 52 with FileLock

use of java.nio.channels.FileLock in project bnd by bndtools.

the class CAFS method write.

/**
	 * Store an input stream in the CAFS while calculating and returning the
	 * SHA-1 code.
	 * 
	 * @param in The input stream to store.
	 * @return The SHA-1 code.
	 * @throws Exception if anything goes wrong
	 */
public SHA1 write(InputStream in) throws Exception {
    Deflater deflater = new Deflater();
    MessageDigest md = MessageDigest.getInstance(ALGORITHM);
    DigestInputStream din = new DigestInputStream(in, md);
    ByteArrayOutputStream bout = new ByteArrayOutputStream();
    DeflaterOutputStream dout = new DeflaterOutputStream(bout, deflater);
    copy(din, dout);
    synchronized (store) {
        // First check if it already exists
        SHA1 sha1 = new SHA1(md.digest());
        long search = index.search(sha1.digest());
        if (search > 0)
            return sha1;
        byte[] compressed = bout.toByteArray();
        // we need to append this file to our store,
        // which requires a lock. However, we are in a race
        // so others can get the lock between us getting
        // the length and someone else getting the lock.
        // So we must verify after we get the lock that the
        // length was unchanged.
        FileLock lock = null;
        try {
            long insertPoint;
            int recordLength = compressed.length + HEADERLENGTH;
            while (true) {
                insertPoint = store.length();
                lock = channel.lock(insertPoint, recordLength, false);
                if (store.length() == insertPoint)
                    break;
                // We got the wrong lock, someone else
                // got in between reading the length
                // and locking
                lock.release();
            }
            int totalLength = deflater.getTotalIn();
            store.seek(insertPoint);
            update(sha1.digest(), compressed, totalLength);
            index.insert(sha1.digest(), insertPoint);
            return sha1;
        } finally {
            if (lock != null)
                lock.release();
        }
    }
}

Example 53 with FileLock

use of java.nio.channels.FileLock in project bnd by bndtools.

the class PersistentMap method put.

public V put(String key, V value) {
    init();
    try {
        V old = null;
        SoftReference<V> ref = cache.get(key);
        if (ref != null)
            old = ref.get();
        FileLock lock = lock();
        try {
            File file = new File(data, key);
            codec.enc().to(file).put(value);
            cache.put(key, new SoftReference<V>(value));
            return old;
        } finally {
            unlock(lock);
        }
    } catch (RuntimeException e) {
        throw e;
    } catch (Exception e) {
        throw new RuntimeException(e);
    }
}

Example 54 with FileLock

use of java.nio.channels.FileLock in project bnd by bndtools.

the class PersistentMap method clear.

public void clear() {
    init();
    try {
        FileLock lock = lock();
        try {
            IO.deleteWithException(data);
            cache.clear();
            IO.mkdirs(data);
        } finally {
            unlock(lock);
        }
    } catch (RuntimeException e) {
        throw e;
    } catch (Exception e) {
        throw new RuntimeException(e);
    }
}

Example 55 with FileLock

use of java.nio.channels.FileLock in project PocketHub by pockethub.

the class RequestWriter method write.

/**
 * Write request to file
 *
 * @param request
 * @return request
 */
public <V> V write(V request) {
    RandomAccessFile dir = null;
    FileLock lock = null;
    ObjectOutputStream output = null;
    try {
        createDirectory(handle.getParentFile());
        dir = new RandomAccessFile(handle, "rw");
        lock = dir.getChannel().lock();
        output = new ObjectOutputStream(new GZIPOutputStream(new FileOutputStream(dir.getFD()), 8192));
        output.writeInt(version);
        output.writeObject(request);
    } catch (IOException e) {
        Log.d(TAG, "Exception writing cache " + handle.getName(), e);
        return null;
    } finally {
        if (output != null) {
            try {
                output.close();
            } catch (IOException e) {
                Log.d(TAG, "Exception closing stream", e);
            }
        }
        if (lock != null) {
            try {
                lock.release();
            } catch (IOException e) {
                Log.d(TAG, "Exception unlocking file", e);
            }
        }
        if (dir != null) {
            try {
                dir.close();
            } catch (IOException e) {
                Log.d(TAG, "Exception closing file", e);
            }
        }
    }
    return request;
}