Example usage for java.nio.file Files newByteChannel

List of usage examples for java.nio.file Files newByteChannel

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Introduction

In this page you can find the example usage for java.nio.file Files newByteChannel.

Prototype

public static SeekableByteChannel newByteChannel(Path path, OpenOption... options) throws IOException

Source Link

Document

Opens or creates a file, returning a seekable byte channel to access the file.

Usage

From source file:Test.java

License:asdf

public static void main(String[] args) throws IOException {
    Path path = Paths.get("/users.txt");

    final String newLine = System.getProperty("line.separator");
    try (SeekableByteChannel sbc = Files.newByteChannel(path, StandardOpenOption.APPEND)) {
        String output = newLine + "asdf" + newLine;
        ByteBuffer buffer = ByteBuffer.wrap(output.getBytes());
        sbc.write(buffer);// w w w .  j a v  a 2s.com
    }

}

From source file:Test.java

License:asdf

public static void main(String[] args) throws IOException {
    Path path = Paths.get("/users.txt");

    final String newLine = System.getProperty("line.separator");
    try (SeekableByteChannel sbc = Files.newByteChannel(path, StandardOpenOption.WRITE)) {
        ByteBuffer buffer;//  w ww  .  j  a  v a  2  s .  co m
        long position = sbc.size();
        sbc.position(position);
        System.out.println("Position: " + sbc.position());

        buffer = ByteBuffer.wrap((newLine + "asdf").getBytes());
        sbc.write(buffer);
        System.out.println("Position: " + sbc.position());
        buffer = ByteBuffer.wrap((newLine + "asdf").getBytes());
        sbc.write(buffer);
        System.out.println("Position: " + sbc.position());
    }
}

From source file:io.horizondb.io.files.DirectFileDataInput.java

/**
 * Creates a new <code>DirectFileDataInput</code> to read data from the specified file.
 * /*from w  w  w .  j  ava  2  s . com*/
 * @param path the file path.
 * @param bufferSize the size of the buffer being used.
 */
public DirectFileDataInput(Path path, int bufferSize) throws IOException {

    notNull(path, "path parameter must not be null");
    isTrue(bufferSize > 0, "the buffer size must be greater than zero");

    this.channel = (FileChannel) Files.newByteChannel(path, StandardOpenOption.READ);

    this.buffer = ByteBuffer.allocateDirect(bufferSize);
    this.slice = Buffers.wrap(this.buffer);

    fillBuffer();
}

From source file:de.bluepair.sci.client.SHAUtils.java

public static <T> Map<String, String> sha512(Path path, Predicate<T> gard, T testValue, long blockSizePref,
        boolean forceBlockSize) {

    if (Files.notExists(path)) {
        return null;
    }//from  www . j a v a  2s  .  c om
    MessageDigest md = getDigest();
    MessageDigest md1 = getDigest();

    if (!gard.test(testValue)) {
        return null;
    }
    long blockSize = blockSizePref;
    long size = -1;
    try {
        size = Files.size(path);
        if (!forceBlockSize) {// maximal 10 hashsummen
            // sonst hab ich zu viele in der datei
            // stehen!
            while (size / blockSize > 10) {
                blockSize += blockSizePref;
            }
        }

    } catch (IOException e) {
        blockSize = blockSizePref;
        return null;
    }

    Map<String, String> map = new HashMap<>();

    long lastStart = 0;

    long stepDown = blockSize;

    try (final SeekableByteChannel fileChannel = Files.newByteChannel(path, StandardOpenOption.READ);) {

        final ByteBuffer buffer = ByteBuffer.allocateDirect(8192);
        int last;
        do {
            if (!gard.test(testValue) || Files.notExists(path)) {
                return null;
            }
            buffer.clear();
            last = fileChannel.read(buffer);

            buffer.flip();
            md.update(buffer);

            // calc 2checksups
            buffer.flip();
            md1.update(buffer);

            if (last > 0) {
                stepDown -= last;
            }

            // wenn ich ein 100mb netzwerk habe
            // ~ca. 5MB bertragung
            // also bei abbruch kann wiederaufgesetzt werden wenn die summen
            // bekannt sind.
            // ~hnlich Blcke berechen also
            // 0-5 c1
            // 0-10 c2
            // 5-10 c3 ...

            if (stepDown <= 0 || (last <= 0)) {
                long len = (blockSize + Math.abs(stepDown));
                if (stepDown > 0) {
                    // kottektur wenn last <0
                    len = blockSize - stepDown;
                }
                stepDown = blockSize;
                map.put("sha512_" + lastStart + "_" + len, Hex.encodeHexString(md1.digest()));
                lastStart += len;
                md1.reset();
            }

        } while (last > 0);

    } catch (IOException ex) {
        Logger.getLogger(FileAnalysis.class.getName()).log(Level.SEVERE, null, ex);
        return null;
    }

    final byte[] sha1hash = md.digest();
    map.put("sha512", Hex.encodeHexString(sha1hash));
    return map;

}

From source file:com.cate.javatransmitter.FileHandler.java

public void setFile(Path inputPath) {
    //TODO add file selection
    this.inputPath = inputPath;
    try {/*from   w  w w . j a va2s  .c om*/
        this.sbc = Files.newByteChannel(inputPath, StandardOpenOption.READ);
        this.nofChunks = (int) Math.ceil((double) (sbc.size()) / packetSize);
        System.out.println("File Size = " + sbc.size() + " Bytes");
        System.out.println("File Size = " + sbc.size() + " Bytes");
    } catch (IOException ex) {
        Logger.getLogger(FileHandler.class.getName()).log(Level.SEVERE, null, ex);
        System.exit(0);
    }
    this.chunkCounter = 0;
    buf = ByteBuffer.allocate(packetSize);

    //catch (IOException x) {
    //    System.out.println("caught exception: " + x);        
    //        return null;
    //    }        
    //            
}

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

private void fileLoop() throws IOException, InterruptedException {
    SeekableByteChannel reader = null;
    InitialPosition nextInitialPosition = _initialPosition;
    try {//w  w w  .ja v a 2s  . com
        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:com.github.horrorho.inflatabledonkey.pcs.xfile.FileAssembler.java

static void truncate(Path file, long to) throws UncheckedIOException {
    // TODO should really limit our written data stream.
    try {//from ww  w.  ja va 2  s . c o m
        if (to == 0) {
            return;
        }

        long size = Files.size(file);
        if (size > to) {
            Files.newByteChannel(file, WRITE).truncate(to).close();
            logger.debug("-- truncate() - truncated: {}, {} > {}", file, size, to);

        } else if (size < to) {
            logger.warn("-- truncate() - cannot truncate: {}, {} > {}", file, size, to);
        }
    } catch (IOException ex) {
        throw new UncheckedIOException(ex);
    }
}

From source file:burstcoin.jminer.core.reader.task.ReaderLoadDriveTask.java

private boolean load(PlotFile plotFile) {
    try (SeekableByteChannel sbc = Files.newByteChannel(plotFile.getFilePath(),
            EnumSet.of(StandardOpenOption.READ))) {
        long currentScoopPosition = scoopNumber * plotFile.getStaggeramt() * MiningPlot.SCOOP_SIZE;

        long partSize = plotFile.getStaggeramt() / plotFile.getNumberOfParts();
        ByteBuffer partBuffer = ByteBuffer.allocate((int) (partSize * MiningPlot.SCOOP_SIZE));
        // optimized plotFiles only have one chunk!
        for (int chunkNumber = 0; chunkNumber < plotFile.getNumberOfChunks(); chunkNumber++) {
            long currentChunkPosition = chunkNumber * plotFile.getStaggeramt() * MiningPlot.PLOT_SIZE;
            sbc.position(currentScoopPosition + currentChunkPosition);
            for (int partNumber = 0; partNumber < plotFile.getNumberOfParts(); partNumber++) {
                sbc.read(partBuffer);//from  w  ww . j  a  v a2  s  .com

                if (Reader.blockNumber != blockNumber) {
                    LOG.trace("loadDriveThread stopped!");
                    partBuffer.clear();
                    sbc.close();
                    return true;
                } else {
                    long chunkPartStartNonce = plotFile.getStartnonce()
                            + (chunkNumber * plotFile.getStaggeramt()) + (partNumber * partSize);
                    final byte[] scoops = partBuffer.array();
                    publisher.publishEvent(new ReaderLoadedPartEvent(blockNumber, scoops, chunkPartStartNonce));
                }
                partBuffer.clear();
            }
        }
        sbc.close();
    } catch (NoSuchFileException exception) {
        LOG.error("File not found ... please restart to rescan plot-files, maybe set rescan to 'true': "
                + exception.getMessage());
    } catch (ClosedByInterruptException e) {
        // we reach this, if we do not wait for task on shutdown - ByteChannel closed by thread interruption
        LOG.trace("reader stopped cause of new block ...");
    } catch (IOException e) {
        LOG.error("IOException: " + e.getMessage());
    }
    return false;
}

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

private void fileLoop() {
    SeekableByteChannel reader = null;
    InitialPosition nextInitialPosition = _initialPosition;
    try {/*from  ww  w.ja v a  2s .c o m*/
        while (isRunning()) {
            // Attempt to open the file
            try {
                reader = Files.newByteChannel(_file, StandardOpenOption.READ);
                LOGGER.trace().setMessage("Opened file").addData("file", _file).log();
            } catch (final NoSuchFileException e) {
                _listener.fileNotFound();
                _trigger.waitOnTrigger();
            }

            if (reader != null) {
                // Position the reader
                resume(reader, nextInitialPosition);
                _listener.fileOpened();

                // Any subsequent file opens we should start at the beginning
                nextInitialPosition = InitialPosition.START;

                // Read the file
                readLoop(reader);

                // Reset per file state
                IOUtils.closeQuietly(reader);
                reader = null;
                _hash = Optional.empty();
            }
        }
        // Clients may elect to kill the stateful tailer on an exception by calling stop, or they
        // may log the exception and continue. In the latter case it is strongly recommended that
        // clients pause before continuing; otherwise, if the error persists the stateful tailer
        // may create non-trivial load on the io subsystem.
        // NOTE: Any non-exception throwable will kill the stateful tailer.
    } catch (final InterruptedException e) {
        Thread.currentThread().interrupt();
        handleThrowable(e);
        // CHECKSTYLE.OFF: IllegalCatch - Allow clients to decide how to handle exceptions
    } catch (final Exception e) {
        // CHECKSTYLE.ON: IllegalCatch
        handleThrowable(e);
    } finally {
        IOUtils.closeQuietly(reader);
        reader = null;
        _hash = Optional.empty();
    }
}

From source file:com.sastix.cms.server.services.content.impl.HashedDirectoryServiceImpl.java

/**
 * Writes file to disk and copy the contents of the input byte array.
 *
 * @param file a Path with file path.//from w ww  . j  a  va  2  s . com
 * @param url  a remote/local url to be saved as file
 * @throws IOException
 */
private void writeFile(final Path file, final URL url) throws IOException {

    if (url.toString().startsWith("jar:file:///")) {
        try {
            writeZipFile(file, url);
        } catch (Exception e) {
            throw new IOException(e);
        }
    } else {

        //Create the file
        SeekableByteChannel sbc = null;
        try {
            //Creates a new Readable Byte channel from URL
            final ReadableByteChannel rbc = Channels.newChannel(url.openStream());
            //Create the file
            sbc = Files.newByteChannel(file, FILE_OPEN_OPTIONS);

            //Clears the buffer
            buffer.clear();

            //Read input Channel
            while (rbc.read(buffer) != -1) {
                // prepare the buffer to be drained
                buffer.flip();
                // write to the channel, may block
                sbc.write(buffer);
                // If partial transfer, shift remainder down
                // If buffer is empty, same as doing clear()
                buffer.compact();
            }
            // EOF will leave buffer in fill state
            buffer.flip();
            // make sure the buffer is fully drained.
            while (buffer.hasRemaining()) {
                sbc.write(buffer);
            }
        } finally {
            if (sbc != null) {
                sbc.close();
            }
        }
    }
}