private IColumn validateAndGetColumn(List<Row> rows, ByteBuffer columnName)
throws NotFoundException {
if (rows.isEmpty()) throw new NotFoundException();
if (rows.size() > 1) throw new RuntimeException("Block id returned more than one row");
Row row = rows.get(0);
if (row.cf == null) throw new NotFoundException();
IColumn col = row.cf.getColumn(columnName);
if (col == null || !col.isLive()) throw new NotFoundException();
return col;
}
private LocalOrRemoteBlock getRemoteSubBlock(
ByteBuffer blockId, ByteBuffer sblockId, int offset, ColumnParent subBlockDataPath)
throws TimedOutException, UnavailableException, InvalidRequestException, NotFoundException {
// The column name is the SubBlock id (UUID)
ReadCommand rc =
new SliceByNamesReadCommand(
cfsKeyspace, blockId, subBlockDataPath, Arrays.asList(sblockId));
try {
// CL=ONE as there are NOT multiple versions of the blocks.
List<Row> rows = StorageProxy.read(Arrays.asList(rc), ConsistencyLevel.ONE);
IColumn col = null;
try {
col = validateAndGetColumn(rows, sblockId);
} catch (NotFoundException e) {
// This is a best effort to get the value. Sometimes due to the size of
// the sublocks, the normal replication may time out leaving a replicate without
// the piece of data. Hence we re try with higher CL.
rows = StorageProxy.read(Arrays.asList(rc), ConsistencyLevel.QUORUM);
}
col = validateAndGetColumn(rows, sblockId);
ByteBuffer value = col.value();
if (value.remaining() < offset)
throw new InvalidRequestException("Invalid offset for block of size: " + value.remaining());
LocalOrRemoteBlock block = new LocalOrRemoteBlock();
if (offset > 0) {
ByteBuffer offsetBlock = value.duplicate();
offsetBlock.position(offsetBlock.position() + offset);
block.setRemote_block(offsetBlock);
} else {
block.setRemote_block(value);
}
return block;
} catch (IOException e) {
throw new RuntimeException(e);
} catch (TimeoutException e) {
throw new TimedOutException();
}
}