Example usage for java.nio.channels FileChannel position

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

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Introduction

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

Prototype

public abstract FileChannel position(long newPosition) throws IOException;

Source Link

Document

Sets this channel's file position.

Usage

From source file:org.apache.bookkeeper.bookie.BookieJournalTest.java

private void writeJunkJournal(File journalDir) throws Exception {
    long logId = System.currentTimeMillis();
    File fn = new File(journalDir, Long.toHexString(logId) + ".txn");

    FileChannel fc = new RandomAccessFile(fn, "rw").getChannel();

    ByteBuffer zeros = ByteBuffer.allocate(512);
    fc.write(zeros, 4 * 1024 * 1024);/* w  ww .  ja  v  a 2  s.  c  om*/
    fc.position(0);

    for (int i = 1; i <= 10; i++) {
        fc.write(ByteBuffer.wrap("JunkJunkJunk".getBytes()));
    }
}

From source file:org.multibit.file.FileHandler.java

public static void copyFile(File sourceFile, File destinationFile) throws IOException {
    if (!destinationFile.exists()) {
        destinationFile.createNewFile();
    }//from w w w. java 2 s  .c  om
    FileInputStream fileInputStream = null;
    FileOutputStream fileOutputStream = null;
    FileChannel source = null;
    FileChannel destination = null;
    try {
        fileInputStream = new FileInputStream(sourceFile);
        source = fileInputStream.getChannel();
        fileOutputStream = new FileOutputStream(destinationFile);
        destination = fileOutputStream.getChannel();
        long transfered = 0;
        long bytes = source.size();
        while (transfered < bytes) {
            transfered += destination.transferFrom(source, 0, source.size());
            destination.position(transfered);
        }
    } finally {
        if (source != null) {
            source.close();
            source = null;
        } else if (fileInputStream != null) {
            fileInputStream.close();
            fileInputStream = null;
        }
        if (destination != null) {
            destination.close();
            destination = null;
        } else if (fileOutputStream != null) {
            fileOutputStream.flush();
            fileOutputStream.close();
        }
    }
}

From source file:org.apache.bookkeeper.bookie.BookieJournalTest.java

private void writePreV2Journal(File journalDir, int numEntries) throws Exception {
    long logId = System.currentTimeMillis();
    File fn = new File(journalDir, Long.toHexString(logId) + ".txn");

    FileChannel fc = new RandomAccessFile(fn, "rw").getChannel();

    ByteBuffer zeros = ByteBuffer.allocate(512);
    fc.write(zeros, 4 * 1024 * 1024);//from   w ww. j  a va  2s. c om
    fc.position(0);

    byte[] data = "JournalTestData".getBytes();
    long lastConfirmed = LedgerHandle.INVALID_ENTRY_ID;
    for (int i = 1; i <= numEntries; i++) {
        ByteBuffer packet = ClientUtil.generatePacket(1, i, lastConfirmed, i * data.length, data)
                .toByteBuffer();
        lastConfirmed = i;
        ByteBuffer lenBuff = ByteBuffer.allocate(4);
        lenBuff.putInt(packet.remaining());
        lenBuff.flip();

        fc.write(lenBuff);
        fc.write(packet);
    }
}

From source file:org.neo4j.io.pagecache.impl.SingleFilePageSwapper.java

private long lockPositionWriteVector(long filePageId, FileChannel channel, long fileOffset, ByteBuffer[] srcs)
        throws IOException {
    try {/* w  w  w.j  av  a  2s .com*/
        long toWrite = filePageSize * (long) srcs.length;
        long bytesWritten = 0;
        synchronized (positionLock(channel)) {
            channel.position(fileOffset);
            do {
                bytesWritten += channel.write(srcs);
            } while (bytesWritten < toWrite);
            return bytesWritten;
        }
    } catch (ClosedChannelException e) {
        // AsynchronousCloseException is a subclass of
        // ClosedChannelException, and ClosedByInterruptException is in
        // turn a subclass of AsynchronousCloseException.
        tryReopen(filePageId, e);
        boolean interrupted = Thread.interrupted();
        // Recurse because this is hopefully a very rare occurrence.
        channel = unwrappedChannel(filePageId);
        long bytesWritten = lockPositionWriteVector(filePageId, channel, fileOffset, srcs);
        if (interrupted) {
            Thread.currentThread().interrupt();
        }
        return bytesWritten;
    }
}

From source file:org.neo4j.io.pagecache.impl.SingleFilePageSwapper.java

private long lockPositionReadVector(long filePageId, FileChannel channel, long fileOffset, ByteBuffer[] srcs)
        throws IOException {
    try {/* ww  w .j a  v a  2  s  .  c  o  m*/
        long toRead = filePageSize * (long) srcs.length;
        long read, readTotal = 0;
        synchronized (positionLock(channel)) {
            channel.position(fileOffset);
            do {
                read = channel.read(srcs);
            } while (read != -1 && (readTotal += read) < toRead);
            return readTotal;
        }
    } catch (ClosedChannelException e) {
        // AsynchronousCloseException is a subclass of
        // ClosedChannelException, and ClosedByInterruptException is in
        // turn a subclass of AsynchronousCloseException.
        tryReopen(filePageId, e);
        boolean interrupted = Thread.interrupted();
        // Recurse because this is hopefully a very rare occurrence.
        channel = unwrappedChannel(filePageId);
        long bytesWritten = lockPositionReadVector(filePageId, channel, fileOffset, srcs);
        if (interrupted) {
            Thread.currentThread().interrupt();
        }
        return bytesWritten;
    }
}

From source file:eu.stratosphere.nephele.taskmanager.runtime.EnvelopeConsumptionLog.java

private void loadNextOutstandingEnvelopes() {

    final int pos = this.outstandingEnvelopesAsIntBuffer.position();

    if (pos > 0) {

        final int rem = this.outstandingEnvelopesAsIntBuffer.remaining();

        for (int i = 0; i < rem; ++i) {
            this.outstandingEnvelopesAsIntBuffer.put(i, this.outstandingEnvelopesAsIntBuffer.get(i + pos));
        }//w  ww. j  a va 2s . c o  m

        this.outstandingEnvelopesAsIntBuffer.position(0);
        this.outstandingEnvelopesAsIntBuffer.limit(rem);
    }

    if (this.numberOfEntriesReadFromLog == this.numberOfInitialLogEntries) {
        return;
    }

    FileChannel fc = null;

    try {

        this.outstandingEnvelopesAsByteBuffer
                .position(this.outstandingEnvelopesAsIntBuffer.limit() * SIZE_OF_INTEGER);
        this.outstandingEnvelopesAsByteBuffer.limit(this.outstandingEnvelopesAsByteBuffer.capacity());

        fc = new FileInputStream(this.logFile).getChannel();
        fc.position(this.numberOfEntriesReadFromLog * SIZE_OF_INTEGER);

        int totalBytesRead = 0;

        while (this.outstandingEnvelopesAsByteBuffer.hasRemaining()) {

            final int bytesRead = fc.read(this.outstandingEnvelopesAsByteBuffer);
            if (bytesRead == -1) {
                break;
            }

            totalBytesRead += bytesRead;
        }

        if (totalBytesRead % SIZE_OF_INTEGER != 0) {
            LOG.error("Read " + totalBytesRead + " from " + this.logFile.getAbsolutePath()
                    + ", file may be corrupt");
        }

        final int numberOfNewEntries = totalBytesRead / SIZE_OF_INTEGER;

        this.outstandingEnvelopesAsIntBuffer
                .limit(this.outstandingEnvelopesAsIntBuffer.limit() + numberOfNewEntries);

        this.numberOfEntriesReadFromLog += numberOfNewEntries;

        fc.close();

    } catch (IOException ioe) {
        LOG.error(StringUtils.stringifyException(ioe));
    } finally {

        if (fc != null) {
            try {
                fc.close();
            } catch (IOException ioe) {
            }
        }
    }
}

From source file:org.cloudata.core.commitlog.CommitLogServer.java

public int readLastLog(String dirName) {
    //LOG.debug("readLastLog is called with dirName : " + dirName);

    if (commitLogStoreFile.exists() == false) {
        LOG.warn("A dir directory does not exist");
        return -1;
    }//w ww.  j  a  va 2s  . c  om

    File[] fileList = commitLogStoreFile.listFiles();
    if (fileList == null || fileList.length == 0) {
        LOG.warn("file does not exist");
        return -1;
    }

    File lastFile = null;
    long lastModified = 0l;

    for (int i = 0; i < fileList.length; i++) {
        if (fileList[i].getName().startsWith(dirName) && fileList[i].lastModified() > lastModified) {
            lastFile = fileList[i];
            lastModified = lastFile.lastModified();
        }
    }

    if (lastFile.length() == 0) {
        LOG.warn("the length of the file is zero");
        return -1;
    }

    try {
        FileChannel ch = new FileInputStream(lastFile).getChannel();
        ch.position(0);
        return startFileTransferChannel(dirName, ch);
    } catch (FileNotFoundException e) {
        LOG.warn("File : " + lastFile.getName() + " does not exist", e);
    } catch (IOException e) {
        LOG.warn("Fail to set position to zero", e);
    }
    return -1;
}

From source file:dk.statsbiblioteket.util.LineReaderTest.java

public void testNIO() throws Exception {
    byte[] INITIAL = new byte[] { 1, 2, 3, 4 };
    byte[] EXTRA = new byte[] { 5, 6, 7, 8 };
    byte[] FULL = new byte[] { 1, 2, 3, 4, 5, 6, 7, 8 };
    byte[] FIFTH = new byte[] { 87 };
    byte[] FULL_WITH_FIFTH = new byte[] { 1, 2, 3, 4, 87, 6, 7, 8 };

    // Create temp-file with content
    File temp = createTempFile();
    FileOutputStream fileOut = new FileOutputStream(temp, true);
    fileOut.write(INITIAL);/*from  ww  w. j  av a2 s .  co  m*/
    fileOut.close();

    checkContent("The plain test-file should be correct", temp, INITIAL);
    {
        // Read the 4 bytes
        RandomAccessFile input = new RandomAccessFile(temp, "r");
        FileChannel channelIn = input.getChannel();
        ByteBuffer buffer = ByteBuffer.allocate(4096);
        channelIn.position(0);
        assertEquals("Buffer read should read full length", INITIAL.length, channelIn.read(buffer));
        buffer.position(0);

        checkContent("Using buffer should produce the right bytes", INITIAL, buffer);
        channelIn.close();
        input.close();
    }
    {
        // Fill new buffer
        ByteBuffer outBuffer = ByteBuffer.allocate(4096);
        outBuffer.put(EXTRA);
        outBuffer.flip();
        assertEquals("The limit of the outBuffer should be correct", EXTRA.length, outBuffer.limit());

        // Append new buffer to end
        RandomAccessFile output = new RandomAccessFile(temp, "rw");
        FileChannel channelOut = output.getChannel();
        channelOut.position(INITIAL.length);
        assertEquals("All bytes should be written", EXTRA.length, channelOut.write(outBuffer));
        channelOut.close();
        output.close();
        checkContent("The resulting file should have the full output", temp, FULL);
    }

    {
        // Fill single byte buffer
        ByteBuffer outBuffer2 = ByteBuffer.allocate(4096);
        outBuffer2.put(FIFTH);
        outBuffer2.flip();
        assertEquals("The limit of the second outBuffer should be correct", FIFTH.length, outBuffer2.limit());

        // Insert byte in the middle
        RandomAccessFile output2 = new RandomAccessFile(temp, "rw");
        FileChannel channelOut2 = output2.getChannel();
        channelOut2.position(4);
        assertEquals("The FIFTH should be written", FIFTH.length, channelOut2.write(outBuffer2));
        channelOut2.close();
        output2.close();
        checkContent("The resulting file with fifth should be complete", temp, FULL_WITH_FIFTH);
    }
}

From source file:com.yobidrive.diskmap.buckets.BucketTableManager.java

private void initializeBucketTableFromLastCommittedBucketFile() throws BucketTableManagerException {
    FileInputStream tableStream = null;
    FileChannel fileChannel = null;
    try {/*  w  w  w  . j a v  a 2  s. co m*/
        File latestCommittedFile = getLatestCommitedFile();
        if (latestCommittedFile != null) {
            tableStream = new FileInputStream(latestCommittedFile);
            fileChannel = tableStream.getChannel();
            ByteBuffer buffer = ByteBuffer.allocate(HEADERSIZE);
            fileChannel.position(0L);
            int read = fileChannel.read(buffer);
            if (read < HEADERSIZE) {
                fileChannel.close();
                throw new BucketTableManagerException(
                        "Wrong bucket table header size: " + read + "/" + HEADERSIZE);
            }
            // Check content of header. Start with Big Endian (default for Java)
            buffer.rewind();
            byteOrder = ByteOrder.BIG_ENDIAN;
            buffer.order(byteOrder);
            int magic = buffer.getInt();
            if (magic == MAGICSTART_BADENDIAN) {
                byteOrder = ByteOrder.LITTLE_ENDIAN;
                buffer.order(byteOrder);
            } else if (magic != MAGICSTART) {
                fileChannel.close();
                throw new BucketTableManagerException("Bad header in bucket table file");
            }
            // Read number of buckets
            long headerMapSize = buffer.getLong();
            // Read checkPoint
            NeedlePointer includedCheckpoint = new NeedlePointer();
            includedCheckpoint.getNeedlePointerFromBuffer(buffer);
            // Read second magic number
            magic = buffer.getInt();
            if (magic != MAGICEND) {
                fileChannel.close();
                throw new BucketTableManagerException("Bad header in bucket table file");
            }
            // Check number of buckets against requested map size
            if (headerMapSize != mapSize) {
                // Map size does not match
                fileChannel.close();
                throw new BucketTableManagerException(
                        "Requested map size " + mapSize + " does not match header map size " + headerMapSize);
            }
            // Sets initial checkpoint
            bucketTable.setInitialCheckPoint(includedCheckpoint);
            // Now reads all entries
            logger.info("Hot start: loading buckets...");
            for (int i = 0; i < nbBuffers; i++) {
                bucketTable.prepareBufferForReading(i);
                read = fileChannel.read(bucketTable.getBuffer(i));
                if (read < bucketTable.getBuffer(i).limit())
                    throw new BucketTableManagerException("Incomplete bucket table file "
                            + latestCommittedFile.getName() + ", expected " + mapSize + HEADERSIZE);
                //else
                //   logger.info("Hot start: loaded "+(i+1)*entriesPerBuffer+" buckets"+((i<(nbBuffers-1))?"...":"")) ;
            }
            // Checks second magic marker
            buffer = ByteBuffer.allocate(NeedleLogInfo.INFOSIZE);
            buffer.rewind();
            buffer.limit(INTSIZE);
            if (fileChannel.read(buffer) < INTSIZE)
                throw new BucketTableManagerException(
                        "Incomplete bucket table file, missing secong magic number "
                                + latestCommittedFile.getName());
            buffer.rewind();
            magic = buffer.getInt();
            if (magic != MAGICSTART) {
                fileChannel.close();
                throw new BucketTableManagerException("Bad header in bucket table file");
            }
            // Now reads clean counters
            while (true) {
                buffer.rewind();
                buffer.limit(NeedleLogInfo.INFOSIZE);
                read = fileChannel.read(buffer);
                if (read > 0 && read < NeedleLogInfo.INFOSIZE)
                    throw new BucketTableManagerException("Incomplete bucket table file, log info too short "
                            + latestCommittedFile.getName() + ", expected " + mapSize + HEADERSIZE);
                if (read <= 0)
                    break;
                else {
                    NeedleLogInfo nli = new NeedleLogInfo(useAverage);
                    buffer.rewind();
                    nli.getNeedleLogInfo(buffer);
                    logInfoPerLogNumber.put(new Integer(nli.getNeedleFileNumber()), nli);
                }
            }
            logger.info("Hot start: loaded " + (nbBuffers * entriesPerBuffer) + " buckets");

        } else {
            // Empty file
            bucketTable.setInitialCheckPoint(new NeedlePointer());
            bucketTable.format();
        }
    } catch (IOException ie) {
        throw new BucketTableManagerException("Failed initializing bucket table", ie);
    } catch (BufferUnderflowException bue) {
        throw new BucketTableManagerException("Bucket table too short", bue);
    } finally {
        if (fileChannel != null) {
            try {
                fileChannel.close();
            } catch (IOException ex) {
                throw new BucketTableManagerException("Error while closing file channel", ex);
            }
        }
    }
}

From source file:com.yobidrive.diskmap.buckets.BucketTableManager.java

private void commitBucketTableToDisk() throws BucketTableManagerException {
    File currentFile = null;//  w w  w . j  av  a 2 s  .c o  m
    FileChannel fileChannel = null;
    ByteBuffer headerBuffer = null;
    try {
        logger.warn("Start commit bucket table...");
        if (bucketTable.getRequestedCheckPoint() == null || bucketTable.getRequestedCheckPoint().isEmpty())
            throw new BucketTableManagerException("commit requested while there is no requested checkpoint");
        currentFile = getLatestCommitedFile();
        File nextFile = getNextFile(getLatestCommitedFile());
        fileChannel = (new RandomAccessFile(nextFile, "rw")).getChannel();
        // Write header with empty checkpoint 
        headerBuffer = ByteBuffer.allocate(HEADERSIZE);
        fileChannel.position(0L);
        headerBuffer.putInt(MAGICSTART);
        headerBuffer.putLong(mapSize);
        // NeedlePointer lastCheckPoint = bucketTable.getLastCheckPoint() ; // Reset checkpoint to no checkpoint done
        NeedlePointer lastCheckPoint = new NeedlePointer(); // Empty needle
        lastCheckPoint.putNeedlePointerToBuffer(headerBuffer);
        headerBuffer.putInt(MAGICEND);
        headerBuffer.flip(); // truncate buffer
        fileChannel.write(headerBuffer);
        // Now writes buffers
        for (int i = 0; i < nbBuffers; i++) {
            bucketTable.prepareBufferForWriting(i);
            int written = fileChannel.write(bucketTable.getBuffer(i));
            if (written < bucketTable.getBuffer(i).limit())
                throw new BucketTableManagerException("Incomplete write for bucket table file "
                        + nextFile.getName() + ", expected " + mapSize + HEADERSIZE);
            // else
            // logger.info("Bucket table commit: written "+(i+1)*entriesPerBuffer+" buckets"+((i<(nbBuffers-1))?"...":"")) ;
            try {
                Thread.sleep(10);
            } catch (Throwable th) {

            }
        }
        // Writes second magic number
        ByteBuffer buffer = ByteBuffer.allocate(NeedleLogInfo.INFOSIZE);
        buffer.rewind();
        buffer.limit(INTSIZE);
        buffer.putInt(MAGICSTART);
        buffer.rewind();
        fileChannel.write(buffer);
        // Write Needle Log Info
        Iterator<NeedleLogInfo> it = logInfoPerLogNumber.values().iterator();
        while (it.hasNext()) {
            buffer.rewind();
            buffer.limit(NeedleLogInfo.INFOSIZE);
            NeedleLogInfo nli = it.next();
            nli.putNeedleLogInfo(buffer, true);
            int written = fileChannel.write(buffer);
            if (written < NeedleLogInfo.INFOSIZE)
                throw new BucketTableManagerException(
                        "Incomplete write for bucket table file, writing log infos " + nextFile.getName());
        }
        // Writes checkpoint
        headerBuffer = ByteBuffer.allocate(NeedlePointer.POINTERSIZE);
        headerBuffer.rewind();
        headerBuffer.limit(NeedlePointer.POINTERSIZE);
        // System.out.println("Writing checkpoint in index "+bucketTable.getRequestedCheckPoint()) ;
        bucketTable.getRequestedCheckPoint().putNeedlePointerToBuffer(headerBuffer, true); // Flip buffer after write
        headerBuffer.rewind();
        // fileChannel.force(false) ;
        if (fileChannel.write(headerBuffer, CHECKPOINTOFFSET) < NeedlePointer.POINTERSIZE) {
            throw new BucketTableManagerException("Could not write checkpoint to " + nextFile.getName());
        }
        fileChannel.force(true);
        fileChannel.close();
        if (!nextFile.renameTo(getCommittedFile(nextFile)))
            throw new BucketTableManagerException(
                    "Could not rename " + nextFile.getName() + " to " + getCommittedFile(nextFile).getName());

        logger.warn("Committed bucket table.");
    } catch (IOException ie) {
        throw new BucketTableManagerException("Failed writting bucket table", ie);
    } finally {
        headerBuffer = null; //May ease garbage collection
        if (fileChannel != null) {
            try {
                fileChannel.close();
            } catch (Exception ex) {
                throw new BucketTableManagerException("Failed to close file channel", ex);
            }
        }
    }
    try {
        if (currentFile != null) {
            if (!currentFile.delete())
                logger.error("Failed deleting previous bucket table" + currentFile.getName());
        }
    } catch (Throwable th) {
        logger.error("Failed deleting previous bucket table" + currentFile.getName(), th);
    }
}