java.nio.ByteBuffer.isDirect()方法的使用及代码示例

x33g5p2x  于2022-01-16 转载在 其他  
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本文整理了Java中java.nio.ByteBuffer.isDirect()方法的一些代码示例，展示了ByteBuffer.isDirect()的具体用法。这些代码示例主要来源于Github/Stackoverflow/Maven等平台，是从一些精选项目中提取出来的代码，具有较强的参考意义，能在一定程度帮忙到你。ByteBuffer.isDirect()方法的具体详情如下：
包路径：java.nio.ByteBuffer
类名称：ByteBuffer
方法名：isDirect

ByteBuffer.isDirect介绍

[英]Indicates whether this buffer is direct.
[中]指示此缓冲区是否为直接缓冲区。

代码示例

代码示例来源：origin: apache/incubator-dubbo

@Override
public ChannelBuffer copy(int index, int length) {
  ByteBuffer src;
  try {
    src = (ByteBuffer) buffer.duplicate().position(index).limit(index + length);
  } catch (IllegalArgumentException e) {
    throw new IndexOutOfBoundsException();
  }
  ByteBuffer dst = buffer.isDirect()
      ? ByteBuffer.allocateDirect(length)
      : ByteBuffer.allocate(length);
  dst.put(src);
  dst.clear();
  return new ByteBufferBackedChannelBuffer(dst);
}

代码示例来源：origin: apache/flink

public void setBuffer(@Nonnull ByteBuffer buffer) {
  if (buffer.hasArray()) {
    this.buffer = buffer.array();
    this.position = buffer.arrayOffset() + buffer.position();
    this.end = this.position + buffer.remaining();
  } else if (buffer.isDirect() || buffer.isReadOnly()) {
    // TODO: FLINK-8585 handle readonly and other non array based buffers more efficiently without data copy
    this.buffer = new byte[buffer.remaining()];
    this.position = 0;
    this.end = this.buffer.length;
    buffer.get(this.buffer);
  } else {
    throw new IllegalArgumentException("The given buffer is neither an array-backed heap ByteBuffer, nor a direct ByteBuffer.");
  }
}

代码示例来源：origin: apache/ignite

/** {@inheritDoc} */
  @Override public void restorePage(ByteBuffer compactPage, int pageSize) {
    assert compactPage.isDirect();
    assert compactPage.position() == 0;
    assert compactPage.limit() <= pageSize;

    compactPage.limit(pageSize); // Just add garbage to the end.
  }
}

代码示例来源：origin: redisson/redisson

/**
 * Compress the content in the given input buffer. After the compression,
 * you can retrieve the compressed data from the output buffer [pos() ...
 * limit()) (compressed data size = limit() - pos() = remaining())
 *
 * @param uncompressed buffer[pos() ... limit()) containing the input data
 * @param compressed output of the compressed data. Uses range [pos()..].
 * @return byte size of the compressed data.
 * @throws SnappyError when the input is not a direct buffer
 */
public static int compress(ByteBuffer uncompressed, ByteBuffer compressed)
    throws IOException
{
  if (!uncompressed.isDirect()) {
    throw new SnappyError(SnappyErrorCode.NOT_A_DIRECT_BUFFER, "input is not a direct buffer");
  }
  if (!compressed.isDirect()) {
    throw new SnappyError(SnappyErrorCode.NOT_A_DIRECT_BUFFER, "destination is not a direct buffer");
  }
  // input: uncompressed[pos(), limit())
  // output: compressed
  int uPos = uncompressed.position();
  int uLen = uncompressed.remaining();
  int compressedSize = impl.rawCompress(uncompressed, uPos, uLen, compressed,
      compressed.position());
  //         pos  limit
  // [ ......BBBBBBB.........]
  compressed.limit(compressed.position() + compressedSize);
  return compressedSize;
}

代码示例来源：origin: apache/incubator-dubbo

@Override
public ChannelBuffer getBuffer(ByteBuffer nioBuffer) {
  if (!nioBuffer.isReadOnly() && nioBuffer.isDirect()) {
    return ChannelBuffers.wrappedBuffer(nioBuffer);
  }
  ChannelBuffer buf = getBuffer(nioBuffer.remaining());
  int pos = nioBuffer.position();
  buf.writeBytes(nioBuffer);
  nioBuffer.position(pos);
  return buf;
}

代码示例来源：origin: bytedeco/javacpp

/**
 * For direct buffers, calls {@link Pointer#Pointer(Buffer)}, while for buffers
 * backed with an array, allocates enough memory for the array and copies it.
 *
 * @param buffer the Buffer to reference or copy
 * @see #put(byte[])
 */
public BytePointer(ByteBuffer buffer) {
  super(buffer);
  if (buffer != null && !buffer.isDirect() && buffer.hasArray()) {
    byte[] array = buffer.array();
    allocateArray(array.length - buffer.arrayOffset());
    put(array, buffer.arrayOffset(), array.length - buffer.arrayOffset());
    position(buffer.position());
    limit(buffer.limit());
  }
}
/**

代码示例来源：origin: apache/ignite

/**
 * @param src Source.
 * @param srcPos Source pos.
 * @param dest Destination.
 * @param destPos Destination pos.
 * @param len Length.
 */
private void copy(ByteBuffer src, int srcPos, ByteBuffer dest, int destPos, int len) {
  assert mode != MAPPED;
  if (buf.isDirect()) {
    ByteBuffer src0 = src.duplicate();
    src0.limit(srcPos + len);
    src0.position(srcPos);
    ByteBuffer dest0 = dest.duplicate();
    dest0.limit(destPos + len);
    dest0.position(destPos);
    dest0.put(src0);
  }
  else
    System.arraycopy(src.array(), srcPos, buf.array(), destPos, len);
}

代码示例来源：origin: apache/hbase

/**
 * Reads bytes at the given offset as a short value.
 * @param buf
 * @param offset
 * @return short value at offset
 */
static short getAsShort(ByteBuffer buf, int offset) {
 if (buf.isDirect()) {
  return theUnsafe.getShort(((DirectBuffer) buf).address() + offset);
 }
 return theUnsafe.getShort(buf.array(), BYTE_ARRAY_BASE_OFFSET + buf.arrayOffset() + offset);
}

代码示例来源：origin: apache/ignite

/**
 * @param src Source.
 * @param srcOff Source offset in bytes.
 * @param dst Destination.
 * @param dstOff Destination offset in bytes.
 * @param cnt Bytes count to copy.
 */
public static void copyMemory(ByteBuffer src, long srcOff, ByteBuffer dst, long dstOff, long cnt) {
  byte[] srcArr = src.hasArray() ? src.array() : null;
  byte[] dstArr = dst.hasArray() ? dst.array() : null;
  long srcArrOff = src.hasArray() ? src.arrayOffset() + GridUnsafe.BYTE_ARR_OFF : 0;
  long dstArrOff = dst.hasArray() ? dst.arrayOffset() + GridUnsafe.BYTE_ARR_OFF : 0;
  long srcPtr = src.isDirect() ? GridUnsafe.bufferAddress(src) : 0;
  long dstPtr = dst.isDirect() ? GridUnsafe.bufferAddress(dst) : 0;
  GridUnsafe.copyMemory(srcArr, srcPtr + srcArrOff + srcOff, dstArr, dstPtr + dstArrOff + dstOff, cnt);
}

代码示例来源：origin: org.apache.hadoop/hadoop-common

@Override
public void decompress(ByteBuffer src, ByteBuffer dst)
  throws IOException {
 assert dst.isDirect() : "dst.isDirect()";
 assert src.isDirect() : "src.isDirect()";
 assert dst.remaining() > 0 : "dst.remaining() > 0";
 this.decompressDirect(src, dst);
 endOfInput = !src.hasRemaining();
}

代码示例来源：origin: apache/geode

@Test
public void testChunkCreateDirectByteBuffer() {
 SlabImpl slab = new SlabImpl(1024 * 1024);
 try {
  MemoryAllocatorImpl ma =
    MemoryAllocatorImpl.createForUnitTest(new NullOutOfOffHeapMemoryListener(),
      new NullOffHeapMemoryStats(), new SlabImpl[] {slab});
  ByteBuffer bb = ByteBuffer.allocate(1024);
  for (int i = 0; i < 1024; i++) {
   bb.put((byte) i);
  }
  bb.position(0);
  OffHeapStoredObject c =
    (OffHeapStoredObject) ma.allocateAndInitialize(bb.array(), false, false);
  assertEquals(1024, c.getDataSize());
  if (!Arrays.equals(bb.array(), c.getRawBytes())) {
   fail("arrays are not equal. Expected " + Arrays.toString(bb.array()) + " but found: "
     + Arrays.toString(c.getRawBytes()));
  }
  ByteBuffer dbb = c.createDirectByteBuffer();
  assertEquals(true, dbb.isDirect());
  assertEquals(bb, dbb);
 } finally {
  MemoryAllocatorImpl.freeOffHeapMemory();
 }
}

代码示例来源：origin: org.apache.hadoop/hadoop-hdfs

if (targetBuffer.remaining() == 0) {
 return;
if (targetBuffer.isDirect()) {
 ByteBuffer directCheckSumBuf =
   BUFFER_POOL.getBuffer(true, stripedWriter.getChecksumBuf().length);
} else {
 stripedWriter.getChecksum().calculateChunkedSums(
   targetBuffer.array(), 0, targetBuffer.remaining(),
   stripedWriter.getChecksumBuf(), 0);
while (targetBuffer.remaining() > 0) {
 DFSPacket packet = new DFSPacket(packetBuf,
   stripedWriter.getMaxChunksPerPacket(),

代码示例来源：origin: apache/ignite

/** {@inheritDoc} */
@Override public void setBuffer(ByteBuffer buf) {
  assert buf != null;
  if (this.buf != buf) {
    this.buf = buf;
    heapArr = buf.isDirect() ? null : buf.array();
    baseOff = buf.isDirect() ? GridUnsafe.bufferAddress(buf) : GridUnsafe.BYTE_ARR_OFF;
  }
}

代码示例来源：origin: prestodb/presto

/**
 * Wrap the visible portion of a {@link java.nio.ByteBuffer}.
 */
public static Slice wrappedBuffer(ByteBuffer buffer)
{
  if (buffer.isDirect()) {
    long address = getAddress(buffer);
    return new Slice(null, address + buffer.position(), buffer.remaining(), buffer.capacity(), buffer);
  }
  if (buffer.hasArray()) {
    return new Slice(buffer.array(), buffer.arrayOffset() + buffer.position(), buffer.remaining());
  }
  throw new IllegalArgumentException("cannot wrap " + buffer.getClass().getName());
}

代码示例来源：origin: apache/hive

private static void decompressChunk(
  ByteBuffer src, CompressionCodec codec, ByteBuffer dest) throws IOException {
 int startPos = dest.position(), startLim = dest.limit();
 int startSrcPos = src.position(), startSrcLim = src.limit();
 if (LOG.isTraceEnabled()) {
  LOG.trace("Decompressing " + src.remaining() + " bytes to dest buffer pos "
    + dest.position() + ", limit " + dest.limit());
 }
 codec.reset(); // We always need to call reset on the codec.
 codec.decompress(src, dest);
 dest.position(startPos);
 int newLim = dest.limit();
 if (newLim > startLim) {
  throw new AssertionError("After codec, buffer [" + startPos + ", " + startLim
    + ") became [" + dest.position() + ", " + newLim + ")");
 }
 if (dest.remaining() == 0) {
  throw new IOException("The codec has produced 0 bytes for {" + src.isDirect() + ", "
   + src.position() + ", " + src.remaining() + "} into {" + dest.isDirect() + ", "
   + dest.position()  + ", " + dest.remaining() + "}");
 }
}

代码示例来源：origin: apache/hbase

protected void checkSizeAndGrow(int extra) {
 long capacityNeeded = curBuf.position() + (long) extra;
 if (capacityNeeded > curBuf.limit()) {
  // guarantee it's possible to fit
  if (capacityNeeded > MAX_ARRAY_SIZE) {
   throw new BufferOverflowException();
  }
  // double until hit the cap
  long nextCapacity = Math.min(curBuf.capacity() * 2L, MAX_ARRAY_SIZE);
  // but make sure there is enough if twice the existing capacity is still too small
  nextCapacity = Math.max(nextCapacity, capacityNeeded);
  ByteBuffer newBuf = allocate((int) nextCapacity, curBuf.isDirect());
  curBuf.flip();
  ByteBufferUtils.copyFromBufferToBuffer(curBuf, newBuf);
  curBuf = newBuf;
 }
}

代码示例来源：origin: apache/incubator-dubbo

@Override
public ChannelBuffer getBuffer(ByteBuffer nioBuffer) {
  if (!nioBuffer.isReadOnly() && nioBuffer.isDirect()) {
    return ChannelBuffers.wrappedBuffer(nioBuffer);
  }
  ChannelBuffer buf = getBuffer(nioBuffer.remaining());
  int pos = nioBuffer.position();
  buf.writeBytes(nioBuffer);
  nioBuffer.position(pos);
  return buf;
}

代码示例来源：origin: bytedeco/javacpp

/**
 * For direct buffers, calls {@link Pointer#Pointer(Buffer)}, while for buffers
 * backed with an array, allocates enough memory for the array and copies it.
 *
 * @param buffer the Buffer to reference or copy
 * @see #put(boolean[])
 */
public BooleanPointer(ByteBuffer buffer) {
  super(buffer);
  if (buffer != null && !buffer.isDirect() && buffer.hasArray()) {
    byte[] array = buffer.array();
    allocateArray(array.length - buffer.arrayOffset());
    for (int i = buffer.arrayOffset(); i < array.length; i++) {
      put(i - buffer.arrayOffset(), array[i] != 0);
    }
    position(buffer.position());
    limit(buffer.limit());
  }
}
/**

代码示例来源：origin: apache/hbase

/**
 * Reads bytes at the given offset as an int value.
 * @param buf
 * @param offset
 * @return int value at offset
 */
static int getAsInt(ByteBuffer buf, int offset) {
 if (buf.isDirect()) {
  return theUnsafe.getInt(((DirectBuffer) buf).address() + offset);
 }
 return theUnsafe.getInt(buf.array(), BYTE_ARRAY_BASE_OFFSET + buf.arrayOffset() + offset);
}

代码示例来源：origin: com.google.protobuf/protobuf-java

/**
 * Decodes the given portion of the {@link ByteBuffer} into a {@link String}.
 *
 * @throws InvalidProtocolBufferException if the portion of the buffer is not valid UTF-8.
 */
final String decodeUtf8(ByteBuffer buffer, int index, int size)
  throws InvalidProtocolBufferException {
 if (buffer.hasArray()) {
  final int offset = buffer.arrayOffset();
  return decodeUtf8(buffer.array(), offset + index, size);
 } else if (buffer.isDirect()) {
  return decodeUtf8Direct(buffer, index, size);
 }
 return decodeUtf8Default(buffer, index, size);
}

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