*
*/
public Row resolve(List<Message> responses) throws DigestMismatchException
{
long startTime = System.currentTimeMillis();
Row retRow = null;
List<Row> rowList = new ArrayList<Row>();
List<EndPoint> endPoints = new ArrayList<EndPoint>();
String key = null;
String table = null;
byte[] digest = new byte[0];
boolean isDigestQuery = false;
/*
* Populate the list of rows from each of the messages
* Check to see if there is a digest query. If a digest
* query exists then we need to compare the digest with
* the digest of the data that is received.
*/
DataInputBuffer bufIn = new DataInputBuffer();
for (Message response : responses)
{
byte[] body = response.getMessageBody();
bufIn.reset(body, body.length);
try
{
long start = System.currentTimeMillis();
ReadResponse result = ReadResponse.serializer().deserialize(bufIn);
if (logger_.isDebugEnabled())
logger_.debug( "Response deserialization time : " + (System.currentTimeMillis() - start) + " ms.");
if(!result.isDigestQuery())
{
rowList.add(result.row());
endPoints.add(response.getFrom());
key = result.row().key();
table = result.row().getTable();
}
else
{
digest = result.digest();
isDigestQuery = true;
}
}
catch( IOException ex )
{
logger_.info(LogUtil.throwableToString(ex));
}
}
// If there was a digest query compare it with all the data digests
// If there is a mismatch then throw an exception so that read repair can happen.
if(isDigestQuery)
{
for(Row row: rowList)
{
if( !Arrays.equals(row.digest(), digest) )
{
/* Wrap the key as the context in this exception */
throw new DigestMismatchException(row.key());
}
}
}
/* If the rowList is empty then we had some exception above. */
if ( rowList.size() == 0 )
{
return retRow;
}
/* Now calculate the resolved row */
retRow = new Row(table, key);
for (int i = 0 ; i < rowList.size(); i++)
{
retRow.repair(rowList.get(i));
}
// At this point we have the return row .
// Now we need to calculate the difference
// so that we can schedule read repairs
for (int i = 0 ; i < rowList.size(); i++)
{
// since retRow is the resolved row it can be used as the super set
Row diffRow = rowList.get(i).diff(retRow);
if(diffRow == null) // no repair needs to happen
continue;
// create the row mutation message based on the diff and schedule a read repair
RowMutation rowMutation = new RowMutation(table, key);
for (ColumnFamily cf : diffRow.getColumnFamilies())
{
rowMutation.add(cf);
}
RowMutationMessage rowMutationMessage = new RowMutationMessage(rowMutation);
ReadRepairManager.instance().schedule(endPoints.get(i),rowMutationMessage);