Example usage for java.nio ByteBuffer rewind

List of usage examples for java.nio ByteBuffer rewind

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Introduction

In this page you can find the example usage for java.nio ByteBuffer rewind.

Prototype

public final Buffer rewind()

Source Link

Document

Rewinds this buffer.

Usage

From source file:org.cosmo.common.record.Defn.java

public Object readAll(int maxCounts) throws IOException {
    int count = Math.min(readCount(), maxCounts);
    byte[] buf = readFullRawBytes(maxCounts).array();
    ByteBuffer readDataIO = ByteBuffer.allocate(size());
    Object elements = null;/*  www .j  a  v  a2s  .  c o  m*/

    if (this instanceof DefnRecord) {
        elements = Array.newInstance(long.class, count);
        for (int i = 0, offset = 0, size = size(), c = count; i < c; i++, offset += size) {
            readDataIO.put(buf, offset, size);
            readDataIO.rewind();
            readDataIO.get(); // skip header byte
            Array.set(elements, i, readDataIO.getLong());
            readDataIO.rewind();
        }
    } else {
        elements = Array.newInstance(field().getType(), count);
        for (int i = 0, offset = 0, size = size(), c = count; i < c; i++, offset += size) {
            readDataIO.put(buf, offset, size);
            readDataIO.rewind();
            readDataIO.get(); // skip header byte
            Array.set(elements, i, readImpl(readDataIO, false));
            readDataIO.rewind();
        }
    }

    return elements;
}

From source file:org.carbondata.query.aggregator.impl.CustomAggregatorHelper.java

/**
 * Below method will be used to read the level files
 *
 * @param memberFile/*from w w  w .ja  v a2  s  . co m*/
 * @param fileName
 * @throws IOException
 */
private void readLevelFileAndUpdateCache(File memberFile, String fileName) throws IOException {
    FileInputStream fos = null;
    FileChannel fileChannel = null;
    try {
        // create an object of FileOutputStream
        fos = new FileInputStream(memberFile);

        fileChannel = fos.getChannel();
        Map<Integer, String> memberMap = surrogateKeyMap.get(fileName);

        if (null == memberMap) {
            memberMap = new HashMap<Integer, String>(CarbonCommonConstants.DEFAULT_COLLECTION_SIZE);
            surrogateKeyMap.put(fileName, memberMap);
        }

        long size = fileChannel.size();
        int maxKey = 0;
        ByteBuffer rowlengthToRead = null;
        int len = 0;
        ByteBuffer row = null;
        int toread = 0;
        byte[] bb = null;
        String value = null;
        int surrogateValue = 0;

        boolean enableEncoding = Boolean.valueOf(
                CarbonProperties.getInstance().getProperty(CarbonCommonConstants.ENABLE_BASE64_ENCODING,
                        CarbonCommonConstants.ENABLE_BASE64_ENCODING_DEFAULT));

        while (fileChannel.position() < size) {
            rowlengthToRead = ByteBuffer.allocate(4);
            fileChannel.read(rowlengthToRead);
            rowlengthToRead.rewind();
            len = rowlengthToRead.getInt();
            if (len == 0) {
                continue;
            }

            row = ByteBuffer.allocate(len);
            fileChannel.read(row);
            row.rewind();
            toread = row.getInt();
            bb = new byte[toread];
            row.get(bb);

            if (enableEncoding) {
                value = new String(Base64.decodeBase64(bb), Charset.defaultCharset());
            } else {
                value = new String(bb, Charset.defaultCharset());
            }

            surrogateValue = row.getInt();
            memberMap.put(surrogateValue, value);

            // check if max key is less than Surrogate key then update the max key
            if (maxKey < surrogateValue) {
                maxKey = surrogateValue;
            }
        }

    } finally {
        CarbonUtil.closeStreams(fileChannel, fos);
    }
}

From source file:jext2.DataInode.java

/**
 * Write data in buffer to disk. This works best when whole blocks which
 * are a multiple of blocksize in size are written. Partial blocks are
 * written by first reading the block and then writing the new data
 * to that buffer than write that new buffer to disk.
 * @throws NoSpaceLeftOnDevice/*from ww  w.  j av a 2  s.  c o m*/
 * @throws FileTooLarge
 */
public int writeData(ByteBuffer buf, long offset) throws JExt2Exception, NoSpaceLeftOnDevice, FileTooLarge {
    /*
     * Note on sparse file support:
     * getBlocksAllocate does not care if there are holes. Just write as much
     * blocks as the buffer requires at the desired location an set inode.size
     * accordingly.
     */

    int blocksize = superblock.getBlocksize();
    long start = offset / blocksize;
    long end = (buf.capacity() + blocksize) / blocksize + start;
    int startOff = (int) (offset % blocksize);

    if (startOff > 0)
        end += 1;

    buf.rewind();

    while (start < end) {
        LinkedList<Long> blockNrs = accessData().getBlocksAllocate(start, 1);
        int bytesLeft = buf.capacity() - buf.position();

        if (bytesLeft < blocksize || startOff > 0) { /* write partial block */
            ByteBuffer onDisk = blockAccess.read(blockNrs.getFirst());

            onDisk.position(startOff);

            assert onDisk.limit() == blocksize;

            buf.limit(buf.position() + Math.min(bytesLeft, onDisk.remaining()));

            onDisk.put(buf);

            onDisk.position(startOff);
            blockAccess.writeFromBufferUnsynchronized((blockNrs.getFirst() & 0xffffffff) * blocksize, onDisk);
        } else { /* write whole block */
            buf.limit(buf.position() + blocksize);

            blockAccess.writeFromBufferUnsynchronized((blockNrs.getFirst() & 0xffffffff) * blocksize, buf);
        }

        start += 1;
        startOff = 0;
        accessData().unlockHierarchyChanges();

    }
    int written = buf.position();
    assert written == buf.capacity();

    /* increase inode.size if we grew the file */
    if (offset + written > getSize()) { /* file grew */
        setStatusChangeTime(new Date());
        setSize(offset + written);
    }

    return written;
}

From source file:com.github.ambry.utils.UtilsTest.java

@Test
public void testReadBuffers() throws IOException {
    byte[] buf = new byte[40004];
    new Random().nextBytes(buf);
    ByteBuffer inputBuf = ByteBuffer.wrap(buf);
    inputBuf.putInt(0, 40000);//  ww w.  jav a 2s.c o m
    ByteBuffer outputBuf = Utils.readIntBuffer(new DataInputStream(new ByteBufferInputStream(inputBuf)));
    for (int i = 0; i < 40000; i++) {
        Assert.assertEquals(buf[i + 4], outputBuf.array()[i]);
    }
    // 0 size
    inputBuf.rewind();
    inputBuf.putInt(0, 0);
    outputBuf = Utils.readIntBuffer(new DataInputStream(new ByteBufferInputStream(inputBuf)));
    Assert.assertEquals("Output should be of length 0", 0, outputBuf.array().length);
    // negative size
    inputBuf.rewind();
    inputBuf.putInt(0, -1);
    try {
        Utils.readIntBuffer(new DataInputStream(new ByteBufferInputStream(inputBuf)));
        Assert.fail("Should have encountered exception with negative length.");
    } catch (IllegalArgumentException e) {
    }

    buf = new byte[10];
    new Random().nextBytes(buf);
    inputBuf = ByteBuffer.wrap(buf);
    inputBuf.putShort(0, (short) 8);
    outputBuf = Utils.readShortBuffer(new DataInputStream(new ByteBufferInputStream(inputBuf)));
    for (int i = 0; i < 8; i++) {
        Assert.assertEquals(buf[i + 2], outputBuf.array()[i]);
    }
    // 0 size
    inputBuf.rewind();
    inputBuf.putShort(0, (short) 0);
    outputBuf = Utils.readShortBuffer(new DataInputStream(new ByteBufferInputStream(inputBuf)));
    Assert.assertEquals("Output should be of length 0", 0, outputBuf.array().length);
    // negative size
    inputBuf.rewind();
    inputBuf.putShort(0, (short) -1);
    try {
        Utils.readShortBuffer(new DataInputStream(new ByteBufferInputStream(inputBuf)));
        Assert.fail("Should have encountered exception with negative length.");
    } catch (IllegalArgumentException e) {
    }
}

From source file:io.github.dsheirer.source.tuner.hackrf.HackRFTunerController.java

@Override
public void setTunedFrequency(long frequency) throws SourceException {
    ByteBuffer buffer = ByteBuffer.allocateDirect(8);
    buffer.order(ByteOrder.LITTLE_ENDIAN);

    int mhz = (int) (frequency / 1E6);
    int hz = (int) (frequency - (mhz * 1E6));

    buffer.putInt(mhz);/*w  w w.  ja  v a  2  s. c o m*/
    buffer.putInt(hz);

    buffer.rewind();

    try {
        write(Request.SET_FREQUENCY, 0, 0, buffer);
    } catch (UsbException e) {
        mLog.error("error setting frequency [" + frequency + "]", e);

        throw new SourceException("error setting frequency [" + frequency + "]", e);
    }
}

From source file:org.apache.hadoop.crypto.CryptoStreamsTestBase.java

private void byteBufferReadCheck(InputStream in, ByteBuffer buf, int bufPos) throws Exception {
    buf.position(bufPos);/*from   w  ww .j  a v a2 s.  c o  m*/
    int n = ((ByteBufferReadable) in).read(buf);
    Assert.assertEquals(bufPos + n, buf.position());
    byte[] readData = new byte[n];
    buf.rewind();
    buf.position(bufPos);
    buf.get(readData);
    byte[] expectedData = new byte[n];
    System.arraycopy(data, 0, expectedData, 0, n);
    Assert.assertArrayEquals(readData, expectedData);
}

From source file:org.apache.hadoop.hbase.client.coprocessor.AggregationClient.java

/**
 * It computes average while fetching sum and row count from all the
 * corresponding regions. Approach is to compute a global sum of region level
 * sum and rowcount and then compute the average.
 * @param table/*w w w.j av  a 2 s  . c  om*/
 * @param scan
 * @throws Throwable
 */
private <R, S, P extends Message, Q extends Message, T extends Message> Pair<S, Long> getAvgArgs(
        final HTable table, final ColumnInterpreter<R, S, P, Q, T> ci, final Scan scan) throws Throwable {
    final AggregateRequest requestArg = validateArgAndGetPB(scan, ci, false);
    class AvgCallBack implements Batch.Callback<Pair<S, Long>> {
        S sum = null;
        Long rowCount = 0l;

        public synchronized Pair<S, Long> getAvgArgs() {
            return new Pair<S, Long>(sum, rowCount);
        }

        @Override
        public synchronized void update(byte[] region, byte[] row, Pair<S, Long> result) {
            sum = ci.add(sum, result.getFirst());
            rowCount += result.getSecond();
        }
    }
    AvgCallBack avgCallBack = new AvgCallBack();
    table.coprocessorService(AggregateService.class, scan.getStartRow(), scan.getStopRow(),
            new Batch.Call<AggregateService, Pair<S, Long>>() {
                @Override
                public Pair<S, Long> call(AggregateService instance) throws IOException {
                    ServerRpcController controller = new ServerRpcController();
                    BlockingRpcCallback<AggregateResponse> rpcCallback = new BlockingRpcCallback<AggregateResponse>();
                    instance.getAvg(controller, requestArg, rpcCallback);
                    AggregateResponse response = rpcCallback.get();
                    if (controller.failedOnException()) {
                        throw controller.getFailedOn();
                    }
                    Pair<S, Long> pair = new Pair<S, Long>(null, 0L);
                    if (response.getFirstPartCount() == 0) {
                        return pair;
                    }
                    ByteString b = response.getFirstPart(0);
                    T t = ProtobufUtil.getParsedGenericInstance(ci.getClass(), 4, b);
                    S s = ci.getPromotedValueFromProto(t);
                    pair.setFirst(s);
                    ByteBuffer bb = ByteBuffer.allocate(8).put(getBytesFromResponse(response.getSecondPart()));
                    bb.rewind();
                    pair.setSecond(bb.getLong());
                    return pair;
                }
            }, avgCallBack);
    return avgCallBack.getAvgArgs();
}

From source file:org.apache.hadoop.hbase.client.coprocessor.AggregationClient.java

/**
 * It computes average while fetching sum and row count from all the
 * corresponding regions. Approach is to compute a global sum of region level
 * sum and rowcount and then compute the average.
 * @param table/* w w w. ja  v  a  2  s.co m*/
 * @param scan
 * @throws Throwable
 */
private <R, S, P extends Message, Q extends Message, T extends Message> Pair<S, Long> getAvgArgs(
        final HTable table, final ColumnInterpreter<R, S, P, Q, T> ci, final Scan scan) throws Throwable {
    final AggregateRequest requestArg = validateArgAndGetPB(scan, ci, false);
    class AvgCallBack implements Batch.Callback<Pair<S, Long>> {
        S sum = null;
        Long rowCount = 0l;

        public Pair<S, Long> getAvgArgs() {
            return new Pair<S, Long>(sum, rowCount);
        }

        @Override
        public synchronized void update(byte[] region, byte[] row, Pair<S, Long> result) {
            sum = ci.add(sum, result.getFirst());
            rowCount += result.getSecond();
        }
    }
    AvgCallBack avgCallBack = new AvgCallBack();
    table.coprocessorService(AggregateService.class, scan.getStartRow(), scan.getStopRow(),
            new Batch.Call<AggregateService, Pair<S, Long>>() {
                @Override
                public Pair<S, Long> call(AggregateService instance) throws IOException {
                    ServerRpcController controller = new ServerRpcController();
                    BlockingRpcCallback<AggregateResponse> rpcCallback = new BlockingRpcCallback<AggregateResponse>();
                    instance.getAvg(controller, requestArg, rpcCallback);
                    AggregateResponse response = rpcCallback.get();
                    if (controller.failedOnException()) {
                        throw controller.getFailedOn();
                    }
                    Pair<S, Long> pair = new Pair<S, Long>(null, 0L);
                    if (response.getFirstPartCount() == 0) {
                        return pair;
                    }
                    ByteString b = response.getFirstPart(0);
                    T t = ProtobufUtil.getParsedGenericInstance(ci.getClass(), 4, b);
                    S s = ci.getPromotedValueFromProto(t);
                    pair.setFirst(s);
                    ByteBuffer bb = ByteBuffer.allocate(8).put(getBytesFromResponse(response.getSecondPart()));
                    bb.rewind();
                    pair.setSecond(bb.getLong());
                    return pair;
                }
            }, avgCallBack);
    return avgCallBack.getAvgArgs();
}

From source file:org.apache.hadoop.hbase.client.transactional.TransactionalAggregationClient.java

/**
 * It gives the row count, by summing up the individual results obtained from
 * regions. In case the qualifier is null, FirstKeyValueFilter is used to
 * optimised the operation. In case qualifier is provided, I can't use the
 * filter as it may set the flag to skip to next row, but the value read is
 * not of the given filter: in this case, this particular row will not be
 * counted ==> an error.//from  w w  w.  ja  v a 2s  . c  om
 * @param table
 * @param ci
 * @param scan
 * @return <R, S>
 * @throws Throwable
 */
public <R, S, P extends Message, Q extends Message, T extends Message> long rowCount(final long transactionId,
        final TransactionalTable table, final ColumnInterpreter<R, S, P, Q, T> ci, final Scan scan)
        throws Throwable {
    byte[] currentBeginKey = scan.getStartRow();
    HRegionInfo currentRegion = table.getRegionLocation(currentBeginKey).getRegionInfo();
    com.google.protobuf.ByteString regionName = ByteString.copyFromUtf8(currentRegion.getRegionNameAsString());
    final TransactionalAggregateRequest requestArg = validateArgAndGetPB(regionName, transactionId, scan, ci,
            true);
    class RowNumCallback implements Batch.Callback<Long> {
        private final AtomicLong rowCountL = new AtomicLong(0);

        public long getRowNumCount() {
            return rowCountL.get();
        }

        @Override
        public void update(byte[] region, byte[] row, Long result) {
            rowCountL.addAndGet(result.longValue());
        }
    }
    RowNumCallback rowNum = new RowNumCallback();
    table.coprocessorService(TrxRegionService.class, scan.getStartRow(), scan.getStopRow(),
            new Batch.Call<TrxRegionService, Long>() {
                @Override
                public Long call(TrxRegionService instance) throws IOException {
                    ServerRpcController controller = new ServerRpcController();
                    BlockingRpcCallback<TransactionalAggregateResponse> rpcCallback = new BlockingRpcCallback<TransactionalAggregateResponse>();
                    instance.getRowNum(controller, requestArg, rpcCallback);
                    TransactionalAggregateResponse response = rpcCallback.get();
                    if (controller.failedOnException()) {
                        throw controller.getFailedOn();
                    }
                    byte[] bytes = getBytesFromResponse(response.getFirstPart(0));
                    ByteBuffer bb = ByteBuffer.allocate(8).put(bytes);
                    bb.rewind();
                    return bb.getLong();
                }
            }, rowNum);
    return rowNum.getRowNumCount();
}

From source file:org.alfresco.repo.content.AbstractWritableContentStoreTest.java

/**
 * Tests random access reading//w  w w .  jav  a 2 s.com
 * <p>
 * Only executes if the reader implements {@link RandomAccessContent}.
 */
@Test
public void testRandomAccessRead() throws Exception {
    ContentWriter writer = getWriter();
    // put some content
    String content = "ABC";
    byte[] bytes = content.getBytes();
    writer.putContent(content);
    ContentReader reader = writer.getReader();

    FileChannel fileChannel = reader.getFileChannel();
    assertNotNull("No channel given", fileChannel);

    // check that no other content access is allowed
    try {
        reader.getReadableChannel();
        fail("Second channel access allowed");
    } catch (RuntimeException e) {
        // expected
    }

    // read the content
    ByteBuffer buffer = ByteBuffer.allocate(bytes.length);
    int count = fileChannel.read(buffer);
    assertEquals("Incorrect number of bytes read", bytes.length, count);
    // transfer back to array
    buffer.rewind();
    buffer.get(bytes);
    String checkContent = new String(bytes);
    assertEquals("Content read failure", content, checkContent);
    fileChannel.close();
}