Example usage for java.nio.channels FileChannel truncate

List of usage examples for java.nio.channels FileChannel truncate

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Introduction

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

Prototype

public abstract FileChannel truncate(long size) throws IOException;

Source Link

Document

Truncates this channel's file to the given size.

Usage

From source file:com.streamsets.pipeline.stage.origin.logtail.TestFileTailSource.java

@Test
public void testFileTruncatedBetweenRuns() throws Exception {
    File testDataDir = new File("target", UUID.randomUUID().toString());
    Assert.assertTrue(testDataDir.mkdirs());
    File file = new File(testDataDir, "file.txt-1");
    Files.write(file.toPath(), Arrays.asList("A", "B", "C"), StandardCharsets.UTF_8);

    FileInfo fileInfo = new FileInfo();
    fileInfo.fileFullPath = testDataDir.getAbsolutePath() + "/file.txt-${PATTERN}";
    fileInfo.fileRollMode = FileRollMode.PATTERN;
    fileInfo.firstFile = "";
    fileInfo.patternForToken = "[0-9]";
    Source source = createSourceForPeriodicFile(testDataDir.getAbsolutePath() + "/file.txt-${PATTERN}",
            "[0-9]");
    SourceRunner runner = createRunner(source);
    try {/*from   w ww  .jav a2s.  c om*/
        // run till current end and stop pipeline
        runner.runInit();
        StageRunner.Output output = runner.runProduce(null, 10);
        Assert.assertEquals(3, output.getRecords().get("lane").size());
        runner.runDestroy();

        // truncate file
        FileChannel channel = new FileOutputStream(file, true).getChannel();
        channel.truncate(2);
        channel.close();

        // run again, no new data, no error
        source = createSourceForPeriodicFile(testDataDir.getAbsolutePath() + "/file.txt-${PATTERN}", "[0-9]");
        runner = createRunner(source);
        runner.runInit();
        output = runner.runProduce(output.getNewOffset(), 10);
        Assert.assertEquals(0, output.getRecords().get("lane").size());
        runner.runDestroy();

        file = new File(testDataDir, "file.txt-2");
        Files.write(file.toPath(), Arrays.asList("A", "B"), StandardCharsets.UTF_8);

        // run again, new file
        source = createSourceForPeriodicFile(testDataDir.getAbsolutePath() + "/file.txt-${PATTERN}", "[0-9]");
        runner = createRunner(source);
        runner.runInit();
        output = runner.runProduce(output.getNewOffset(), 10);
        Assert.assertEquals(2, output.getRecords().get("lane").size());

    } finally {
        runner.runDestroy();
    }
}

From source file:com.healthmarketscience.jackcess.Database.java

/**
 * Create a new Database for the given fileFormat
 * @param fileFormat version of new database.
 * @param mdbFile Location to write the new database to.  <b>If this file
 *    already exists, it will be overwritten.</b>
 * @param autoSync whether or not to enable auto-syncing on write.  if
 *                 {@code true}, writes will be immediately flushed to disk.
 *                 This leaves the database in a (fairly) consistent state
 *                 on each write, but can be very inefficient for many
 *                 updates.  if {@code false}, flushing to disk happens at
 *                 the jvm's leisure, which can be much faster, but may
 *                 leave the database in an inconsistent state if failures
 *                 are encountered during writing.
 * @param charset Charset to use, if {@code null}, uses default
 * @param timeZone TimeZone to use, if {@code null}, uses default
 * @usage _intermediate_method_/*w w  w .j  a v  a 2s.  c o  m*/
 */
public static Database create(FileFormat fileFormat, File mdbFile, boolean autoSync, Charset charset,
        TimeZone timeZone) throws IOException {
    if (fileFormat.getJetFormat().READ_ONLY) {
        throw new IOException("jet format '" + fileFormat.getJetFormat() + "' does not support writing");
    }

    FileChannel channel = openChannel(mdbFile, false);
    channel.truncate(0);
    transferFrom(channel, getResourceAsStream(fileFormat._emptyFile));
    channel.force(true);
    return new Database(mdbFile, channel, autoSync, fileFormat, charset, timeZone, null);
}

From source file:com.healthmarketscience.jackcess.impl.DatabaseImpl.java

/**
 * Create a new Database for the given fileFormat
 * @param fileFormat version of new database.
 * @param mdbFile Location to write the new database to.  <b>If this file
 *                already exists, it will be overwritten.</b>
 * @param channel  pre-opened FileChannel.  if provided explicitly, it will
 *                 not be closed by this Database instance
 * @param autoSync whether or not to enable auto-syncing on write.  if
 *                 {@code true}, writes will be immediately flushed to disk.
 *                 This leaves the database in a (fairly) consistent state
 *                 on each write, but can be very inefficient for many
 *                 updates.  if {@code false}, flushing to disk happens at
 *                 the jvm's leisure, which can be much faster, but may
 *                 leave the database in an inconsistent state if failures
 *                 are encountered during writing.  Writes may be flushed at
 *                 any time using {@link #flush}.
 * @param charset  Charset to use, if {@code null}, uses default
 * @param timeZone TimeZone to use, if {@code null}, uses default
 * @usage _advanced_method_//from w  w w. ja va  2s  . c  o  m
 */
public static DatabaseImpl create(FileFormat fileFormat, File mdbFile, FileChannel channel, boolean autoSync,
        Charset charset, TimeZone timeZone) throws IOException {
    FileFormatDetails details = getFileFormatDetails(fileFormat);
    if (details.getFormat().READ_ONLY) {
        throw new IOException("file format " + fileFormat + " does not support writing");
    }

    boolean closeChannel = false;
    if (channel == null) {
        channel = openChannel(mdbFile, false);
        closeChannel = true;
    }

    boolean success = false;
    try {
        channel.truncate(0);
        transferFrom(channel, getResourceAsStream(details.getEmptyFilePath()));
        channel.force(true);
        DatabaseImpl db = new DatabaseImpl(mdbFile, channel, closeChannel, autoSync, fileFormat, charset,
                timeZone, null);
        success = true;
        return db;
    } finally {
        if (!success && closeChannel) {
            // something blew up, shutdown the channel (quietly)
            ByteUtil.closeQuietly(channel);
        }
    }
}

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

private void truncate(NeedlePointer needlePointer) throws NeedleManagerException {
    // Truncate current file
    if (needlePointer.getNeedleOffset() < 0) {
        logger.error("Request for truncating " + needlePointer.toString() + "!!!");
        throw new NeedleManagerException("Request for truncating " + needlePointer.toString() + "!!!");
    }/*from  ww w.ja va2  s  .co  m*/
    // truncates current file
    FileChannel fc = getChannel(needlePointer.getNeedleFileNumber());
    if (fc == null) {
        logger.error("Request for truncating " + needlePointer.toString() + ", no File Channel!!!");
        throw new NeedleManagerException(
                "Request for truncating " + needlePointer.toString() + ", no File Channel!!!");
    }
    try {
        fc.truncate(needlePointer.getNeedleOffset());
        fc.force(true);
    } catch (IOException ie) {
        logger.error("Error truncating " + needlePointer.toString(), ie);
        throw new NeedleManagerException("Error truncating " + needlePointer.toString(), ie);
    }
    // Removes subsequent files. In fact just rename them and alert via logger
    int logNumber = needlePointer.getNeedleFileNumber() + 1;
    while (channelMap.contains(new Integer(logNumber))) {
        closeChannel(logNumber);
        File toClose = getFile(logNumber);
        if (toClose != null) {
            try {
                toClose.renameTo(new File(toClose.getCanonicalFile() + ".bak"));
            } catch (IOException ie) {
                throw new NeedleManagerException(
                        "Could not rename to .bak for file number " + Integer.toHexString(logNumber));
            }
        }
        logNumber++;
    }
}

From source file:com.clustercontrol.agent.job.PublicKeyThread.java

/**
 *  ?Authorized_key????<BR>/*from  www . ja  va  2s. c  o m*/
 * 
 * @param publicKey
 * @return true : ?false:
 */
private synchronized boolean deleteKey(String publicKey) {
    m_log.debug("delete key start");

    if (SKIP_KEYFILE_UPDATE) {
        m_log.info("skipped deleting publicKey");
        return true;
    }

    Charset charset = Charset.forName("UTF-8");
    CharsetEncoder encoder = charset.newEncoder();
    CharsetDecoder decoder = charset.newDecoder();

    //???
    String fileName = AgentProperties.getProperty(execUser.toLowerCase() + AUTHORIZED_KEY_PATH);
    if (fileName == null || fileName.length() == 0)
        return false;

    //File?
    File fi = new File(fileName);

    RandomAccessFile randomAccessFile = null;
    FileChannel channel = null;
    FileLock lock = null;
    boolean delete = false;
    try {
        //RandomAccessFile?
        randomAccessFile = new RandomAccessFile(fi, "rw");
        //FileChannel?
        channel = randomAccessFile.getChannel();

        // 
        for (int i = 0; i < (FILELOCK_TIMEOUT / FILELOCK_WAIT); i++) {
            if (null != (lock = channel.tryLock())) {
                break;
            }
            m_log.info("waiting for locked file... [" + (i + 1) + "/" + (FILELOCK_TIMEOUT / FILELOCK_WAIT)
                    + " : " + fileName + "]");
            Thread.sleep(FILELOCK_WAIT);
        }
        if (null == lock) {
            m_log.warn("file locking timeout.");
            return false;
        }

        // (?)
        synchronized (authKeyLock) {
            //??
            ByteBuffer buffer = ByteBuffer.allocate((int) channel.size());

            //??
            channel.read(buffer);

            // ???????????0?
            buffer.flip();

            //??
            String contents = decoder.decode(buffer).toString();

            // ?
            m_log.debug("contents " + contents.length() + " : " + contents);

            //??
            List<String> keyCheck = new ArrayList<String>();
            StringTokenizer tokenizer = new StringTokenizer(contents, "\n");
            while (tokenizer.hasMoreTokens()) {
                keyCheck.add(tokenizer.nextToken());
            }

            //??????
            int s = keyCheck.lastIndexOf(publicKey);
            if (s != -1) {
                // ?
                m_log.debug("remobe key : " + keyCheck.get(s));
                keyCheck.remove(s);
            }

            //?????
            encoder.reset();
            buffer.clear();

            int i;
            if (keyCheck.size() > 0) {
                for (i = 0; i < keyCheck.size() - 1; i++) {
                    encoder.encode(CharBuffer.wrap(keyCheck.get(i) + "\n"), buffer, false);
                }
                encoder.encode(CharBuffer.wrap(keyCheck.get(i)), buffer, true);
            }

            //???
            buffer.flip();
            channel.truncate(0);
            channel.position(0);
            channel.write(buffer);
        }

        delete = true;
    } catch (IOException e) {
        m_log.error(e.getMessage(), e);
    } catch (RuntimeException e) {
        m_log.error(e.getMessage(), e);
    } catch (InterruptedException e) {
        m_log.error(e.getMessage(), e);
    } finally {
        try {
            if (channel != null) {
                channel.close();
            }
            if (randomAccessFile != null) {
                randomAccessFile.close();
            }
            //?
            if (lock != null) {
                lock.release();
            }
        } catch (Exception e) {
        }
    }

    return delete;
}

From source file:org.alfresco.repo.search.impl.lucene.index.IndexInfo.java

private void writeStatusToFile(FileChannel channel) throws IOException {
    long size = getBufferSize();

    ByteBuffer buffer;//  w ww.  j av a  2 s .c  om
    if (useNIOMemoryMapping) {
        MappedByteBuffer mbb = channel.map(MapMode.READ_WRITE, 0, size);
        mbb.load();
        buffer = mbb;
    } else {
        channel.truncate(size);
        buffer = ByteBuffer.wrap(new byte[(int) size]);
    }

    buffer.position(0);

    buffer.putLong(version);
    CRC32 crc32 = new CRC32();
    crc32.update((int) (version >>> 32) & 0xFFFFFFFF);
    crc32.update((int) (version >>> 0) & 0xFFFFFFFF);

    buffer.putInt(indexEntries.size());
    crc32.update(indexEntries.size());

    for (IndexEntry entry : indexEntries.values()) {
        String entryType = entry.getType().toString();
        writeString(buffer, crc32, entryType);

        writeString(buffer, crc32, entry.getName());

        writeString(buffer, crc32, entry.getParentName());

        String entryStatus = entry.getStatus().toString();
        writeString(buffer, crc32, entryStatus);

        writeString(buffer, crc32, entry.getMergeId());

        buffer.putLong(entry.getDocumentCount());
        crc32.update((int) (entry.getDocumentCount() >>> 32) & 0xFFFFFFFF);
        crc32.update((int) (entry.getDocumentCount() >>> 0) & 0xFFFFFFFF);

        buffer.putLong(entry.getDeletions());
        crc32.update((int) (entry.getDeletions() >>> 32) & 0xFFFFFFFF);
        crc32.update((int) (entry.getDeletions() >>> 0) & 0xFFFFFFFF);

        buffer.put(entry.isDeletOnlyNodes() ? (byte) 1 : (byte) 0);
        crc32.update(entry.isDeletOnlyNodes() ? new byte[] { (byte) 1 } : new byte[] { (byte) 0 });
    }
    buffer.putLong(crc32.getValue());

    if (useNIOMemoryMapping) {
        ((MappedByteBuffer) buffer).force();
    } else {
        buffer.rewind();
        channel.position(0);
        channel.write(buffer);
    }
}

From source file:com.MainFiles.Functions.java

public int createStan() {
    int x = 0;/* w  w  w . jav  a 2s  .c o m*/

    String filename = COUNT_FILE;
    File inwrite = new File(filename);

    // Get a file channel for the file
    try {
        FileChannel channel = new RandomAccessFile(inwrite, "rw").getChannel();
        // Use the file channel to create a lock on the file.
        // This method blocks until it can retrieve the lock.
        FileLock lock = channel.lock();
        //  if(!inwrite.exists()) {
        String s = "";
        try {
            int fileSize = (int) channel.size();
            //    System.out.println("int is" + fileSize);
            ByteBuffer bafa = ByteBuffer.allocate(fileSize);
            int numRead = 0;
            while (numRead >= 0) {
                numRead = channel.read(bafa);
                bafa.rewind();
                for (int i = 0; i < numRead; i++) {
                    int b = (int) bafa.get();
                    char c = (char) b;
                    s = s + c;
                }
            }

            x = Integer.parseInt(s);
            if (x > 999999) {
                x = 100000;
            } else if (x < 100000) {
                x = 100000;
            }
            x = ++x;
            String xx = String.valueOf(x);
            byte[] yy = xx.getBytes();
            channel.truncate(0);
            channel.write(ByteBuffer.wrap(yy));
            // channel.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
        lock.release();
        // Close the file
        channel.close();
    } catch (FileNotFoundException e) {
        String message = "The file " + inwrite.getName() + " does not exist. So no input can be written on it";
        System.out.println(message);
        e.printStackTrace();
        //log to error file
    } catch (IOException e) {
        System.out.println("Problem writing to the logfile " + inwrite.getName());

    }

    filename = "";
    return x;
}