public void Map(PlatformMemoryStream stream)
{
IList <IClusterNode> subgrid;
ClusterGroupImpl prj = (ClusterGroupImpl)_compute.ClusterGroup;
var ignite = (Ignite)prj.Ignite;
// 1. Unmarshal topology info if topology changed.
var reader = prj.Marshaller.StartUnmarshal(stream);
if (reader.ReadBoolean())
{
long topVer = reader.ReadLong();
List <IClusterNode> nodes = new List <IClusterNode>(reader.ReadInt());
int nodesCnt = reader.ReadInt();
subgrid = new List <IClusterNode>(nodesCnt);
for (int i = 0; i < nodesCnt; i++)
{
IClusterNode node = ignite.GetNode(reader.ReadGuid());
nodes.Add(node);
if (reader.ReadBoolean())
{
subgrid.Add(node);
}
}
// Update parent projection to help other task callers avoid this overhead.
// Note that there is a chance that topology changed even further and this update fails.
// It means that some of subgrid nodes could have left the Grid. This is not critical
// for us, because Java will handle it gracefully.
prj.UpdateTopology(topVer, nodes);
}
else
{
IList <IClusterNode> nodes = prj.NodesNoRefresh();
Debug.Assert(nodes != null, "At least one topology update should have occurred.");
subgrid = IgniteUtils.Shuffle(nodes);
}
// 2. Perform map.
IDictionary <IComputeJob <T>, IClusterNode> map;
Exception err;
try
{
map = _task.Map(subgrid, _arg);
err = null;
}
catch (Exception e)
{
map = null;
err = e;
// Java can receive another exception in case of marshalling failure but it is not important.
Finish(default(TR), e);
}
// 3. Write map result to the output stream.
stream.Reset();
BinaryWriter writer = prj.Marshaller.StartMarshal(stream);
try
{
if (err == null)
{
writer.WriteBoolean(true); // Success flag.
if (map == null)
{
writer.WriteBoolean(false); // Map produced no result.
}
else
{
writer.WriteBoolean(true); // Map produced result.
_jobHandles = WriteJobs(writer, map);
}
}
else
{
writer.WriteBoolean(false); // Map failed.
// Write error as string because it is not important for Java, we need only to print
// a message in the log.
writer.WriteString("Map step failed [errType=" + err.GetType().Name +
", errMsg=" + err.Message + ']');
}
}
catch (Exception e)
{
// Something went wrong during marshaling.
Finish(default(TR), e);
stream.Reset();
writer.WriteBoolean(false); // Map failed.
writer.WriteString(e.Message); // Write error message.
}
finally
{
prj.Marshaller.FinishMarshal(writer);
}
}
