Example usage for java.nio.channels SeekableByteChannel position

List of usage examples for java.nio.channels SeekableByteChannel position

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Introduction

In this page you can find the example usage for java.nio.channels SeekableByteChannel position.

Prototype

SeekableByteChannel position(long newPosition) throws IOException;

Source Link

Document

Sets this channel's position.

Usage

From source file:com.spectralogic.ds3client.helpers.RequestMatchers.java

private static String channelToString(final SeekableByteChannel channel) {
    try {//from  w ww.  ja  v a 2 s.  c o m
        channel.position(0);
        return IOUtils.toString(Channels.newReader(channel, "UTF-8"));
    } catch (final IOException e) {
        throw new RuntimeException(e);
    }
}

From source file:com.spectralogic.ds3client.helpers.channels.WindowedSeekableByteChannel_Test.java

private static SeekableByteChannel stringToChannel(final String string) throws IOException {
    final SeekableByteChannel channel = new ByteArraySeekableByteChannel();
    writeToChannel(string, channel);//w ww .  j  a v  a  2 s .c  o m
    channel.position(0);
    return channel;
}

From source file:io.neba.core.logviewer.Tail.java

@Override
public void run() {
    SeekableByteChannel channel = null;

    try {//  w  w  w .java 2s . co m
        channel = newByteChannel(this.file.toPath(), READ);

        long availableInByte = this.file.length();
        long startingFromInByte = max(availableInByte - this.bytesToTail, 0);

        channel.position(startingFromInByte);

        long position = startingFromInByte;
        long totalBytesRead = 0L;

        // Read up to this amount of data from the file at once.
        ByteBuffer readBuffer = allocate(4096);
        while (!this.stopped) {

            // The file might be temporarily gone during rotation. Wait, then decide
            // whether the file is considered gone permanently or whether a rotation has occurred.
            if (!this.file.exists()) {
                sleep(AWAIT_FILE_ROTATION_MILLIS);
            }
            if (!this.file.exists()) {
                this.remoteEndpoint.sendString("file not found");
                return;
            }

            if (position > this.file.length()) {
                this.remoteEndpoint.sendString("file rotated");
                position = 0;
                closeQuietly(channel);
                channel = newByteChannel(this.file.toPath(), READ);
            }

            int read = channel.read(readBuffer);

            if (read == -1) {
                if (mode == TAIL) {
                    // EOF, we are done.
                    return;
                }
                // If we are in follow mode, reaching the end of the file might signal a file rotation. Sleep and re-try.
                sleep(TAIL_CHECK_INTERVAL_MILLIS);
                continue;
            }

            totalBytesRead += read;

            position = channel.position();
            readBuffer.flip();
            this.remoteEndpoint.sendBytes(readBuffer);
            readBuffer.clear();

            if (mode == TAIL && totalBytesRead >= this.bytesToTail) {
                return;
            }
        }
    } catch (IOException e) {
        this.logger.error("Unable to tail " + this.file.getAbsolutePath() + ".", e);
    } catch (InterruptedException e) {
        if (!this.stopped) {
            this.logger.error("Stopped tailing " + this.file.getAbsolutePath() + ", got interrupted.", e);
        }
    } finally {
        closeQuietly(channel);
    }
}

From source file:org.cryptomator.crypto.aes256.Aes256Cryptor.java

@Override
public Long decryptedContentLength(SeekableByteChannel encryptedFile) throws IOException {
    // skip 128bit IV + 256 bit MAC:
    encryptedFile.position(48);/*from ww  w. ja v  a 2s  .c  om*/

    // read encrypted value:
    final ByteBuffer encryptedFileSizeBuffer = ByteBuffer.allocate(AES_BLOCK_LENGTH);
    final int numFileSizeBytesRead = encryptedFile.read(encryptedFileSizeBuffer);

    // return "unknown" value, if EOF
    if (numFileSizeBytesRead != encryptedFileSizeBuffer.capacity()) {
        return null;
    }

    // decrypt size:
    try {
        final Cipher sizeCipher = aesEcbCipher(primaryMasterKey, Cipher.DECRYPT_MODE);
        final byte[] decryptedFileSize = sizeCipher.doFinal(encryptedFileSizeBuffer.array());
        final ByteBuffer fileSizeBuffer = ByteBuffer.wrap(decryptedFileSize);
        return fileSizeBuffer.getLong();
    } catch (IllegalBlockSizeException | BadPaddingException e) {
        throw new IllegalStateException(e);
    }
}

From source file:com.arpnetworking.metrics.common.tailer.StatefulTailer.java

private void resume(final SeekableByteChannel reader, final InitialPosition initialPosition)
        throws IOException {
    // Attempt to resume from checkpoint
    long position = initialPosition.get(reader);

    // Override position with last known position from store
    _hash = computeHash(reader, REQUIRED_BYTES_FOR_HASH);
    if (_hash.isPresent()) {
        final Optional<Long> storedPosition = _positionStore.getPosition(_hash.get());
        if (storedPosition.isPresent()) {
            // Optionally limit the size of the backlog to process
            final long fileSize = reader.size();
            if (_maximumOffsetOnResume.isPresent()
                    && fileSize - storedPosition.get() > _maximumOffsetOnResume.get()) {
                position = fileSize - _maximumOffsetOnResume.get();
                // TODO(vkoskela): Discard the current potentially partial line [AINT-584]
            } else {
                position = storedPosition.get();
            }/*from   w w  w .j a  v a2 s  .co  m*/
        }
    }

    LOGGER.info().setMessage("Starting tailer").addData("file", _file).addData("position", position).log();

    reader.position(position);
}

From source file:com.arpnetworking.tsdcore.tailer.StatefulTailer.java

private void fileLoop() throws IOException, InterruptedException {
    SeekableByteChannel reader = null;
    InitialPosition nextInitialPosition = _initialPosition;
    try {/*from   w w  w . j  a va2 s .  c  o m*/
        while (isRunning()) {
            // Attempt to open the file
            try {
                reader = Files.newByteChannel(_file.toPath(), StandardOpenOption.READ);
                LOGGER.trace(String.format("Opened file; file=%s", _file));
            } catch (final NoSuchFileException e) {
                _listener.fileNotFound();
                _trigger.waitOnTrigger();
            }

            if (reader != null) {
                // Attempt to resume from checkpoint
                long position = nextInitialPosition.get(reader);
                // Any subsequent file opens we should start at the beginning
                nextInitialPosition = InitialPosition.START;
                _hash = computeHash(reader, REQUIRED_BYTES_FOR_HASH);
                if (_hash.isPresent()) {
                    position = _positionStore.getPosition(_hash.get()).or(position).longValue();
                }
                LOGGER.trace(
                        String.format("Starting tail; file=%s, position=%d", _file, Long.valueOf(position)));
                reader.position(position);

                // Read the file
                readLoop(reader);

                // Reset per file state
                IOUtils.closeQuietly(reader);
                reader = null;
                _hash = Optional.absent();
            }
        }
    } finally {
        IOUtils.closeQuietly(reader);
        reader = null;
        _hash = Optional.absent();
    }
}

From source file:org.cryptomator.crypto.aes256.Aes256Cryptor.java

@Override
public boolean authenticateContent(SeekableByteChannel encryptedFile) throws IOException {
    // init mac:/*from w w  w  .j a  va 2 s .  co  m*/
    final Mac calculatedMac = this.hmacSha256(hMacMasterKey);

    // read stored mac:
    encryptedFile.position(16);
    final ByteBuffer storedMac = ByteBuffer.allocate(calculatedMac.getMacLength());
    final int numMacBytesRead = encryptedFile.read(storedMac);

    // check validity of header:
    if (numMacBytesRead != calculatedMac.getMacLength()) {
        throw new IOException("Failed to read file header.");
    }

    // read all encrypted data and calculate mac:
    encryptedFile.position(64);
    final InputStream in = new SeekableByteChannelInputStream(encryptedFile);
    final InputStream macIn = new MacInputStream(in, calculatedMac);
    IOUtils.copyLarge(macIn, new NullOutputStream());

    // compare (in constant time):
    return MessageDigest.isEqual(storedMac.array(), calculatedMac.doFinal());
}

From source file:org.cryptomator.crypto.aes256.Aes256Cryptor.java

@Override
public Long decryptedFile(SeekableByteChannel encryptedFile, OutputStream plaintextFile) throws IOException {
    // read iv://from w  w  w  . j ava2 s . c  o  m
    encryptedFile.position(0);
    final ByteBuffer countingIv = ByteBuffer.allocate(AES_BLOCK_LENGTH);
    final int numIvBytesRead = encryptedFile.read(countingIv);

    // read file size:
    final Long fileSize = decryptedContentLength(encryptedFile);

    // check validity of header:
    if (numIvBytesRead != AES_BLOCK_LENGTH || fileSize == null) {
        throw new IOException("Failed to read file header.");
    }

    // go to begin of content:
    encryptedFile.position(64);

    // generate cipher:
    final Cipher cipher = this.aesCtrCipher(primaryMasterKey, countingIv.array(), Cipher.DECRYPT_MODE);

    // read content
    final InputStream in = new SeekableByteChannelInputStream(encryptedFile);
    final InputStream cipheredIn = new CipherInputStream(in, cipher);
    return IOUtils.copyLarge(cipheredIn, plaintextFile, 0, fileSize);
}

From source file:org.cryptomator.crypto.aes256.Aes256Cryptor.java

@Override
public Long decryptRange(SeekableByteChannel encryptedFile, OutputStream plaintextFile, long pos, long length)
        throws IOException {
    // read iv:/* w  w  w  .j a  v  a2 s. com*/
    encryptedFile.position(0);
    final ByteBuffer countingIv = ByteBuffer.allocate(AES_BLOCK_LENGTH);
    final int numIvBytesRead = encryptedFile.read(countingIv);

    // check validity of header:
    if (numIvBytesRead != AES_BLOCK_LENGTH) {
        throw new IOException("Failed to read file header.");
    }

    // seek relevant position and update iv:
    long firstRelevantBlock = pos / AES_BLOCK_LENGTH; // cut of fraction!
    long beginOfFirstRelevantBlock = firstRelevantBlock * AES_BLOCK_LENGTH;
    long offsetInsideFirstRelevantBlock = pos - beginOfFirstRelevantBlock;
    countingIv.putLong(AES_BLOCK_LENGTH - Long.BYTES, firstRelevantBlock);

    // fast forward stream:
    encryptedFile.position(64 + beginOfFirstRelevantBlock);

    // generate cipher:
    final Cipher cipher = this.aesCtrCipher(primaryMasterKey, countingIv.array(), Cipher.DECRYPT_MODE);

    // read content
    final InputStream in = new SeekableByteChannelInputStream(encryptedFile);
    final InputStream cipheredIn = new CipherInputStream(in, cipher);
    return IOUtils.copyLarge(cipheredIn, plaintextFile, offsetInsideFirstRelevantBlock, length);
}