How to use

position

method

in

org.apache.mina.codec.IoBuffer

private IoBuffer() {
  limit(0);
  position(0);
  mark = null;
}

/**
 * @see ByteBuffer#rewind()
 */
public IoBuffer rewind() {
  position(0);
  mark = getPointerByPosition(-1);
  return this;
}

/**
 * @see ByteBuffer#remaining()
 */
public int remaining() {
  return limit() - position();
}

@Override
public String toString() {
  StringBuilder sb = new StringBuilder();
  sb.append(getClass().getName());
  sb.append("[pos=");
  sb.append(position());
  sb.append(" lim=");
  sb.append(limit());
  sb.append(" cap=");
  sb.append(capacity());
  sb.append("]");
  return sb.toString();
}

/**
 * @see ByteBuffer#compact()
 */
public IoBuffer compact() {
  for (int i = 0; i < remaining(); i++) {
    put(i, get(i + position.getPosition()));
  }
  position(limit() - position());
  limit(capacity);
  mark = null;
  return this;
}

/**
 * Returns a copy of the current {@link IoBuffer}, with an independent copy
 * of the position, limit and mark.
 * 
 * @return the copied {@link IoBuffer}
 */
public IoBuffer duplicate() {
  IoBuffer buffer = new IoBuffer();
  for (BufferNode node = head; node != null; node = node.getNext()) {
    ByteBuffer byteBuffer = node.getBuffer().duplicate();
    byteBuffer.rewind();
    buffer.enqueue(byteBuffer);
  }
  buffer.position(position());
  buffer.limit(limit());
  buffer.mark = mark != null ? getPointerByPosition(mark.getPosition()) : null;
  buffer.readonly = readonly;
  return buffer;
}

/**
 * Test the position method with a negative value
 */
@Test(expected = IllegalArgumentException.class)
public void testPositionNegativeValue() {
  ByteBuffer bb1 = ByteBuffer.allocate(4);
  bb1.put("0123".getBytes());
  bb1.flip();
  ByteBuffer bb2 = ByteBuffer.allocate(4);
  bb2.put("4567".getBytes());
  bb2.flip();
  ByteBuffer bb3 = ByteBuffer.allocate(4);
  bb3.put("89".getBytes());
  bb3.flip();
  IoBuffer ioBuffer = IoBuffer.wrap(bb1, bb2, bb3);
  ioBuffer.position(-1);
}

/**
 * Test the position method with a value above the buffer size
 */
@Test(expected = IllegalArgumentException.class)
public void testPositionAboveValue() {
  ByteBuffer bb1 = ByteBuffer.allocate(4);
  bb1.put("012".getBytes());
  bb1.flip();
  ByteBuffer bb2 = ByteBuffer.allocate(4);
  bb2.put("3456".getBytes());
  bb2.flip();
  ByteBuffer bb3 = ByteBuffer.allocate(4);
  bb3.put("789".getBytes());
  bb3.flip();
  // The resulting buffer will be seen as "0123456789"
  IoBuffer ioBuffer = IoBuffer.wrap(bb1, bb2, bb3);
  ioBuffer.position(11);
}

/**
 * Test the position method over an emptyIoBuffer
 */
@Test
public void testPositionIntEmptyBuffer() {
  IoBuffer ioBuffer = IoBuffer.newInstance();
  ioBuffer.position(0);
}

@Test
public void testInputStreamGetByte() throws IOException {
  String hw = "HelloWorld";
  IoBuffer bb = IoBuffer.wrap(hw.getBytes());
  InputStream is = bb.asInputStream();
  for (int i = 0; i < 10; i++) {
    assertEquals(i, bb.position());
    assertEquals(hw.getBytes()[i], is.read());
  }
  assertEquals(-1, is.read());
}

@Test
public void testInputStreamGetByteArray() throws IOException {
  String hw = "HelloWorld";
  IoBuffer bb = IoBuffer.wrap(hw.getBytes());
  InputStream is = bb.asInputStream();
  byte array[] = new byte[15];
  assertEquals(5, is.read(array, 0, 5));
  assertEquals(5, bb.position());
  assertEquals(5, is.read(array, 5, 10));
  assertEquals(10, bb.position());
  for (int i = 0; i < 10; i++) {
    assertEquals(hw.getBytes()[i], array[i]);
  }
}

/**
 * Test the position method over an emptyIoBuffer
 */
@Test
public void testPositionEmptyBuffer() {
  IoBuffer ioBuffer = IoBuffer.newInstance();
  assertEquals(0, ioBuffer.position());
}

@Override
public OUT decode(IoBuffer input, MutableInt nextBlockSize) {
  OUT output = null;
  if (nextBlockSize.getValue() == null) {
    nextBlockSize.setValue(sizeDecoder.decode(input));
  }
  if (nextBlockSize.isDefined() && (input.remaining() >= nextBlockSize.getValue())) {
    IoBuffer buffer = input.slice();
    buffer.limit(buffer.position() + nextBlockSize.getValue());
    output = payloadDecoder.decode(buffer);
    nextBlockSize.reset();
  }
  return output;
}

@Test
public void testFloat() {
  for (ByteOrder bo : new ByteOrder[] { ByteOrder.BIG_ENDIAN, ByteOrder.LITTLE_ENDIAN }) {
    ByteBuffer bb = (ByteBuffer) ByteBuffer.allocate(5).order(bo).putFloat(-0.68f).rewind();
    IoBuffer ioBuffer = IoBuffer.wrap(bb).order(bo);
    assertEquals(5, ioBuffer.capacity());
    ioBuffer.extend(3);
    ioBuffer.position(4);
    assertEquals(8, ioBuffer.capacity());
    ioBuffer.putFloat(3.14f);
    ioBuffer.rewind();
    assertEquals(-0.68f, ioBuffer.getFloat(), 0.001f);
    assertEquals(3.14f, ioBuffer.getFloat(), 0.001f);
    ioBuffer.rewind();
    ioBuffer.putFloat(2, -12.34f);
    assertEquals(-12.34f, ioBuffer.getFloat(2), 0.001f);
  }
}

@Test
public void testDouble() {
  for (ByteOrder bo : new ByteOrder[] { ByteOrder.BIG_ENDIAN, ByteOrder.LITTLE_ENDIAN }) {
    ByteBuffer bb = (ByteBuffer) ByteBuffer.allocate(9).order(bo).putDouble(Math.PI).rewind();
    IoBuffer ioBuffer = IoBuffer.wrap(bb).order(bo);
    assertEquals(9, ioBuffer.capacity());
    ioBuffer.extend(7);
    ioBuffer.position(8);
    assertEquals(16, ioBuffer.capacity());
    ioBuffer.putDouble(-Math.E);
    ioBuffer.rewind();
    assertEquals(Math.PI, ioBuffer.getDouble(), 1E-10);
    assertEquals(-Math.E, ioBuffer.getDouble(), 1E-10);
    ioBuffer.rewind();
    ioBuffer.putDouble(4, 12.34);
    assertEquals(12.34, ioBuffer.getDouble(4), 1E-10);
  }
}

@Test
public void testTruncatedValues() {
  for (int value : new int[] { 0, 1, 127, 128, 65536, 198649, Integer.MAX_VALUE }) {
    IoBuffer buffer = IoBuffer.wrap(encoder.encode(value));
    for (int i = 0; i < buffer.remaining(); i++) {
      IoBuffer partialBuffer = buffer.slice();
      partialBuffer.limit(partialBuffer.position() + i);
      try {
        assertNull(decoder.decode(partialBuffer));
      } catch (ProtocolDecoderException e) {
        fail("Should not throw exception");
      }
    }
  }
}

/**
 * Test the allocation of a new heap IoBuffer with 1024 bytes
 */
@Test
public void testAllocate1024() {
  IoBuffer ioBuffer = IoBuffer.allocate(1024);
  assertFalse(ioBuffer.isDirect());
  assertEquals(1024, ioBuffer.capacity());
  assertEquals(1024, ioBuffer.limit());
  assertEquals(0, ioBuffer.position());
  assertTrue(ioBuffer.hasRemaining());
}

/**
 * Test the allocation of a new direct IoBuffer with 1024 bytes
 */
@Test
public void testAllocateDirect1024() {
  IoBuffer ioBuffer = IoBuffer.allocateDirect(1024);
  assertTrue(ioBuffer.isDirect());
  assertEquals(1024, ioBuffer.capacity());
  assertEquals(1024, ioBuffer.limit());
  assertEquals(0, ioBuffer.position());
  assertTrue(ioBuffer.hasRemaining());
}

/**
 * Test the allocation of a new heap IoBuffer with no byte in it
 */
@Test
public void testAllocate0() {
  IoBuffer ioBuffer = IoBuffer.allocate(0);
  assertFalse(ioBuffer.isDirect());
  assertEquals(0, ioBuffer.capacity());
  assertEquals(0, ioBuffer.limit());
  assertEquals(0, ioBuffer.position());
  assertFalse(ioBuffer.hasRemaining());
}

/**
 * Test the allocation of a new direct IoBuffer with no byte in it
 */
@Test
public void testAllocateDirect0() {
  IoBuffer ioBuffer = IoBuffer.allocateDirect(0);
  assertTrue(ioBuffer.isDirect());
  assertEquals(0, ioBuffer.capacity());
  assertEquals(0, ioBuffer.limit());
  assertEquals(0, ioBuffer.position());
  assertFalse(ioBuffer.hasRemaining());
}