/**
* Constructor
* @param node local node
* @param state RPC related state.
* @param task map-reduce task.
* @param args arguments to the map reduce task.
*/
public MapReduceComputation(Node node, object state,
MapReduceTask task,
MapReduceArgs args)
{
_node = node;
_rpc = node.Rpc;
_mr_request_state = state;
_mr_task = task;
_mr_args = args;
//Here is our state variable:
_state = new State();
_result = State.DEFAULT_OBJ;
}
/**
* Allows subscribing new map-reduce tasks to the handler.
* @param task an object representing the map-reduce task.
*/
public void SubscribeTask(MapReduceTask task) {
lock(_sync) {
if (_name_to_task.ContainsKey(task.TaskName)) {
throw new Exception(String.Format("Map reduce task name: {0} already registered.", task.TaskName));
}
_name_to_task[task.TaskName] = task;
}
}
/**
* Constructor
* @param n local node
*/
public MapReduceHandler(Node n) {
_node = n;
_rpc = n.Rpc;
_name_to_task = new Dictionary<string, MapReduceTask>();
_sync = new object();
//Set up some basic tasks:
var basetasks = new MapReduceTask[]{
new MapReduceBoundedBroadcast(_node),
new MapReduceGreedy(_node),
new MapReduceListConcat(_node),
};
foreach(MapReduceTask mrt in basetasks) {
SubscribeTask(mrt);
}
}
/**
* Constructor
* @param node local node
* @param state RPC related state.
* @param task map-reduce task.
* @param args arguments to the map reduce task.
*/
public MapReduceComputation(Node node, object state,
MapReduceTask task,
MapReduceArgs args)
{
_node = node;
_rpc = RpcManager.GetInstance(node);
_mr_request_state = state;
_mr_task = task;
_mr_args = args;
_queue_to_child = new Hashtable();
_sync = new object();
_finished = false;
}
/**
* Starts a map-reduce computation.
* @param task map reduce task to start.
* @param args arguments for the map-reduce task.
* @param req_state RPC related state for the invocation.
*/
protected void Start(MapReduceTask task, MapReduceArgs args, object req_state) {
MapReduceComputation mr = new MapReduceComputation(_node, req_state, task, args);
mr.Start();
}
/**
* Constructor
* @param node local node
* @param state RPC related state.
* @param task map-reduce task.
* @param args arguments to the map reduce task.
*/
public MapReduceComputation(Node node, object state,
MapReduceTask task,
MapReduceArgs args)
{
_node = node;
_rpc = RpcManager.GetInstance(node);
_mr_request_state = state;
_mr_task = task;
_mr_args = args;
_queue_to_child = new Hashtable();
_sync = new object();
_finished = false;
_start_time = DateTime.UtcNow;
//register with the node hearbeat to for computation to finish.
lock(_sync) {
_node.HeartBeatEvent += new EventHandler(this.CheckTimeout);
}
}
