public synchronized void addRecord(Slice record, boolean force)
throws IOException
{
Preconditions.checkState(!closed.get(), "Log has been closed");
SliceInput sliceInput = record.input();
// used to track first, middle and last blocks
boolean begin = true;
// Fragment the record int chunks as necessary and write it. Note that if record
// is empty, we still want to iterate once to write a single
// zero-length chunk.
do {
int bytesRemainingInBlock = BLOCK_SIZE - blockOffset;
Preconditions.checkState(bytesRemainingInBlock >= 0);
// Switch to a new block if necessary
if (bytesRemainingInBlock < HEADER_SIZE) {
if (bytesRemainingInBlock > 0) {
// Fill the rest of the block with zeros
// todo lame... need a better way to write zeros
fileChannel.write(ByteBuffer.allocate(bytesRemainingInBlock));
}
blockOffset = 0;
bytesRemainingInBlock = BLOCK_SIZE - blockOffset;
}
// Invariant: we never leave less than HEADER_SIZE bytes available in a block
int bytesAvailableInBlock = bytesRemainingInBlock - HEADER_SIZE;
Preconditions.checkState(bytesAvailableInBlock >= 0);
// if there are more bytes in the record then there are available in the block,
// fragment the record; otherwise write to the end of the record
boolean end;
int fragmentLength;
if (sliceInput.available() > bytesAvailableInBlock) {
end = false;
fragmentLength = bytesAvailableInBlock;
}
else {
end = true;
fragmentLength = sliceInput.available();
}
// determine block type
LogChunkType type;
if (begin && end) {
type = LogChunkType.FULL;
}
else if (begin) {
type = LogChunkType.FIRST;
}
else if (end) {
type = LogChunkType.LAST;
}
else {
type = LogChunkType.MIDDLE;
}
// write the chunk
writeChunk(type, sliceInput.readSlice(fragmentLength));
// we are no longer on the first chunk
begin = false;
} while (sliceInput.isReadable());
if (force) {
fileChannel.force(false);
}
}