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.util.Util.java

public static long shortsToLong2(short[] shorts) {
    ByteBuffer b = ByteBuffer.allocate(8);
    b.putShort(shorts[0]);//from   w  ww  . j a  v a2 s  . c  om
    b.putShort(shorts[1]);
    b.putShort(shorts[2]);
    b.putShort(shorts[3]);
    b.rewind();
    return b.getLong();
}

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

/**
 * Write a page (or part of a page) to disk
 * @param page Page to write/*from www  .j ava 2  s  .  c om*/
 * @param pageNumber Page number to write the page to
 * @param pageOffset offset within the page at which to start writing the
 *                   page data
 */
public void writePage(ByteBuffer page, int pageNumber, int pageOffset) throws IOException {
    assertWriting();
    validatePageNumber(pageNumber);

    page.rewind().position(pageOffset);

    int writeLen = page.remaining();
    if ((writeLen + pageOffset) > getFormat().PAGE_SIZE) {
        throw new IllegalArgumentException("Page buffer is too large, size " + (writeLen + pageOffset));
    }

    ByteBuffer encodedPage = page;
    if (pageNumber == 0) {
        // re-mask header
        applyHeaderMask(page);
    } else {

        if (!_codecHandler.canEncodePartialPage()) {
            if ((pageOffset > 0) && (writeLen < getFormat().PAGE_SIZE)) {

                // current codec handler cannot encode part of a page, so need to
                // copy the modified part into the current page contents in a temp
                // buffer so that we can encode the entire page
                ByteBuffer fullPage = _fullPageEncodeBufferH.setPage(this, pageNumber);

                // copy the modified part to the full page
                fullPage.position(pageOffset);
                fullPage.put(page);
                fullPage.rewind();

                // reset so we can write the whole page
                page = fullPage;
                pageOffset = 0;
                writeLen = getFormat().PAGE_SIZE;

            } else {

                _fullPageEncodeBufferH.possiblyInvalidate(pageNumber, null);
            }
        }

        // re-encode page
        encodedPage = _codecHandler.encodePage(page, pageNumber, pageOffset);

        // reset position/limit in case they were affected by encoding
        encodedPage.position(pageOffset).limit(pageOffset + writeLen);
    }

    try {
        _channel.write(encodedPage, (getPageOffset(pageNumber) + pageOffset));
    } finally {
        if (pageNumber == 0) {
            // de-mask header
            applyHeaderMask(page);
        }
    }
}

From source file:org.apache.hadoop.hbase.coprocessor.AggregateImplementation.java

/**
 * Gives the row count for the given column family and column qualifier, in
 * the given row range as defined in the Scan object.
 * @throws IOException//from  ww  w . j a va 2  s  . co m
 */
@Override
public void getRowNum(RpcController controller, AggregateRequest request, RpcCallback<AggregateResponse> done) {
    AggregateResponse response = null;
    long counter = 0l;
    List<Cell> results = new ArrayList<Cell>();
    InternalScanner scanner = null;
    try {
        Scan scan = ProtobufUtil.toScan(request.getScan());
        byte[][] colFamilies = scan.getFamilies();
        byte[] colFamily = colFamilies != null ? colFamilies[0] : null;
        NavigableSet<byte[]> qualifiers = colFamilies != null ? scan.getFamilyMap().get(colFamily) : null;
        byte[] qualifier = null;
        if (qualifiers != null && !qualifiers.isEmpty()) {
            qualifier = qualifiers.pollFirst();
        }
        if (scan.getFilter() == null && qualifier == null)
            scan.setFilter(new FirstKeyOnlyFilter());
        scanner = env.getRegion().getScanner(scan);
        boolean hasMoreRows = false;
        do {
            hasMoreRows = scanner.next(results);
            if (results.size() > 0) {
                counter++;
            }
            results.clear();
        } while (hasMoreRows);
        ByteBuffer bb = ByteBuffer.allocate(8).putLong(counter);
        bb.rewind();
        response = AggregateResponse.newBuilder().addFirstPart(ByteString.copyFrom(bb)).build();
    } catch (IOException e) {
        ResponseConverter.setControllerException(controller, e);
    } finally {
        if (scanner != null) {
            try {
                scanner.close();
            } catch (IOException ignored) {
            }
        }
    }
    log.info("Row counter from this region is " + env.getRegion().getRegionNameAsString() + ": " + counter);
    done.run(response);
}

From source file:org.kalypso.grid.BinaryGeoGrid.java

/**
 * @param fillGrid/*from  ww  w . ja v a2  s  .  c  o  m*/
 *          If set to <code>true</code>, the grid will be initially filled with no-data values. Else, the grid values
 *          are undetermined.
 */
public BinaryGeoGrid(final FileChannel channel, final int sizeX, final int sizeY, final int scale,
        final Coordinate origin, final Coordinate offsetX, final Coordinate offsetY, final String sourceCRS,
        final boolean fillGrid) throws GeoGridException {
    super(origin, offsetX, offsetY, sourceCRS);

    m_readBuffer = ByteBuffer.allocate(4 * sizeX * BUFFER_LINES);
    m_readBuffer.order(ByteOrder.BIG_ENDIAN);

    /* create write buffer, also marks this grid as writable */
    m_writeBuffer = ByteBuffer.allocate(4);
    m_writeBuffer.order(ByteOrder.BIG_ENDIAN);

    try {
        m_channel = channel;
        m_binFile = null;

        m_header = new BinaryGeoGridHeader(sizeX, sizeY, scale);

        m_unscaledMin = null;
        m_unscaledMax = null;

        /* Initialize grid */
        // m_randomAccessFile.setLength( HEADER_SIZE + sizeX * sizeY * 4 + 2 * 4 );
        m_channel.truncate(BinaryGeoGridHeader.HEADER_SIZE + sizeX * sizeY * 4 + 2 * 4);

        /* Read header */
        m_channel.position(0);
        m_header.write(m_channel);

        /* Set everything to non-data */
        if (fillGrid) {
            final ByteBuffer buffer = ByteBuffer.allocate(sizeX * 4);
            for (int y = 0; y < sizeY; y++) {
                buffer.rewind();
                for (int x = 0; x < sizeX; x++)
                    buffer.putInt(NO_DATA);
                m_channel.write(buffer);
            }
        }

        /* Read statistical data */
        saveStatistically();
    } catch (final IOException e) {
        throw new GeoGridException("Failed to initiate random access file", e);
    }
}

From source file:org.apache.hadoop.hbase.coprocessor.AggregateImplementation.java

/**
 * Gives a Pair with first object as Sum and second object as row count,
 * computed for a given combination of column qualifier and column family in
 * the given row range as defined in the Scan object. In its current
 * implementation, it takes one column family and one column qualifier (if
 * provided). In case of null column qualifier, an aggregate sum over all the
 * entire column family will be returned.
 * <p>/*  ww  w  . j ava  2 s  .co m*/
 * The average is computed in
 * AggregationClient#avg(byte[], ColumnInterpreter, Scan) by
 * processing results from all regions, so its "ok" to pass sum and a Long
 * type.
 */
@Override
public void getAvg(RpcController controller, AggregateRequest request, RpcCallback<AggregateResponse> done) {
    AggregateResponse response = null;
    InternalScanner scanner = null;
    try {
        ColumnInterpreter<T, S, P, Q, R> ci = constructColumnInterpreterFromRequest(request);
        S sumVal = null;
        Long rowCountVal = 0l;
        Scan scan = ProtobufUtil.toScan(request.getScan());
        scanner = env.getRegion().getScanner(scan);
        byte[] colFamily = scan.getFamilies()[0];
        NavigableSet<byte[]> qualifiers = scan.getFamilyMap().get(colFamily);
        byte[] qualifier = null;
        if (qualifiers != null && !qualifiers.isEmpty()) {
            qualifier = qualifiers.pollFirst();
        }
        List<Cell> results = new ArrayList<Cell>();
        boolean hasMoreRows = false;

        do {
            results.clear();
            hasMoreRows = scanner.next(results);
            for (Cell kv : results) {
                sumVal = ci.add(sumVal, ci.castToReturnType(ci.getValue(colFamily, qualifier, kv)));
            }
            rowCountVal++;
        } while (hasMoreRows);
        if (sumVal != null) {
            ByteString first = ci.getProtoForPromotedType(sumVal).toByteString();
            AggregateResponse.Builder pair = AggregateResponse.newBuilder();
            pair.addFirstPart(first);
            ByteBuffer bb = ByteBuffer.allocate(8).putLong(rowCountVal);
            bb.rewind();
            pair.setSecondPart(ByteString.copyFrom(bb));
            response = pair.build();
        }
    } catch (IOException e) {
        ResponseConverter.setControllerException(controller, e);
    } finally {
        if (scanner != null) {
            try {
                scanner.close();
            } catch (IOException ignored) {
            }
        }
    }
    done.run(response);
}

From source file:org.apache.hadoop.hbase.coprocessor.AggregateImplementation.java

/**
 * Gives a Pair with first object a List containing Sum and sum of squares,
 * and the second object as row count. It is computed for a given combination of
 * column qualifier and column family in the given row range as defined in the
 * Scan object. In its current implementation, it takes one column family and
 * one column qualifier (if provided). The idea is get the value of variance first:
 * the average of the squares less the square of the average a standard
 * deviation is square root of variance.
 *//*  w w  w  .j a v a  2 s.  c om*/
@Override
public void getStd(RpcController controller, AggregateRequest request, RpcCallback<AggregateResponse> done) {
    InternalScanner scanner = null;
    AggregateResponse response = null;
    try {
        ColumnInterpreter<T, S, P, Q, R> ci = constructColumnInterpreterFromRequest(request);
        S sumVal = null, sumSqVal = null, tempVal = null;
        long rowCountVal = 0l;
        Scan scan = ProtobufUtil.toScan(request.getScan());
        scanner = env.getRegion().getScanner(scan);
        byte[] colFamily = scan.getFamilies()[0];
        NavigableSet<byte[]> qualifiers = scan.getFamilyMap().get(colFamily);
        byte[] qualifier = null;
        if (qualifiers != null && !qualifiers.isEmpty()) {
            qualifier = qualifiers.pollFirst();
        }
        List<Cell> results = new ArrayList<Cell>();

        boolean hasMoreRows = false;

        do {
            tempVal = null;
            hasMoreRows = scanner.next(results);
            for (Cell kv : results) {
                tempVal = ci.add(tempVal, ci.castToReturnType(ci.getValue(colFamily, qualifier, kv)));
            }
            results.clear();
            sumVal = ci.add(sumVal, tempVal);
            sumSqVal = ci.add(sumSqVal, ci.multiply(tempVal, tempVal));
            rowCountVal++;
        } while (hasMoreRows);
        if (sumVal != null) {
            ByteString first_sumVal = ci.getProtoForPromotedType(sumVal).toByteString();
            ByteString first_sumSqVal = ci.getProtoForPromotedType(sumSqVal).toByteString();
            AggregateResponse.Builder pair = AggregateResponse.newBuilder();
            pair.addFirstPart(first_sumVal);
            pair.addFirstPart(first_sumSqVal);
            ByteBuffer bb = ByteBuffer.allocate(8).putLong(rowCountVal);
            bb.rewind();
            pair.setSecondPart(ByteString.copyFrom(bb));
            response = pair.build();
        }
    } catch (IOException e) {
        ResponseConverter.setControllerException(controller, e);
    } finally {
        if (scanner != null) {
            try {
                scanner.close();
            } catch (IOException ignored) {
            }
        }
    }
    done.run(response);
}

From source file:voldemort.store.cachestore.impl.ChannelStore.java

/**
 * get keyOffset and len from index channel
 * @param record #//from www  . j  a v  a2 s.  c o m
 * @return key Object
 */
public Key readKey(int record) throws IOException {
    ByteBuffer buf = ByteBuffer.allocate(RECORD_SIZE);
    indexChannel.read(buf, (long) record * RECORD_SIZE + OFFSET);
    buf.rewind();
    byte status = buf.get();
    if (isDeleted(status))
        return null;
    else {
        long key = buf.getLong();
        byte[] keys = readChannel(key, keyChannel);
        return toKey(keys);
    }
}

From source file:org.codehaus.preon.buffer.DefaultBitBuffer.java

public ByteBuffer readAsByteBuffer() {
    ByteBuffer buffer = byteBuffer.duplicate();
    buffer.rewind();
    return buffer;
}

From source file:org.kalypso.grid.BinaryGeoGrid.java

private void saveStatistically() throws GeoGridException {
    final BigDecimal min = getMin();
    final BigDecimal max = getMax();

    try {//  w w w .j  a  va 2  s.  co  m
        m_unscaledMin = unscaleValue(min.doubleValue());
        m_unscaledMax = unscaleValue(max.doubleValue());

        /* directly write into buffer */
        final long pos = BinaryGeoGridHeader.HEADER_SIZE + getSizeX() * getSizeY() * 4;

        final ByteBuffer buffer = ByteBuffer.allocate(8);

        buffer.putInt(m_unscaledMin);
        buffer.putInt(m_unscaledMax);

        m_channel.position(pos);
        buffer.rewind();
        m_channel.write(buffer);
    } catch (final IOException e) {
        throw new GeoGridException("Failed to set statistical data", e);
    }
}

From source file:com.intel.chimera.stream.AbstractCryptoStreamTest.java

private void byteBufferReadCheck(InputStream in, ByteBuffer buf, int bufPos) throws Exception {
    buf.position(bufPos);//from   www  . ja  v a2 s. c o  m
    int n = ((ReadableByteChannel) 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);
}