/**
* Create a new instance of WorkerThread
*
* @param node the FederationNode on which the WorkerMap will be executed
* @param wm the instance of WorkerMap to be executed
* @param tg the ThreadGroup to which this thread is attached
*/
public WorkerThread(FederationNode node, WorkerMap wm, ThreadGroup tg) {
super(tg, "WorkerThread for: " + node.toString());
this.node = node;
this.workerMap = wm;
this.resultList = new ArrayList<Serializable>();
}
/** Overridden run method */
@Override
public void run() {
taskData = getNextTaskData();
while (taskData != null) {
try {
// first initiate a federation request
ArrayList<Serializable> data = new ArrayList<Serializable>();
data.add(taskData);
FederationServiceMapReduceConsumer fsmrc =
new FederationServiceMapReduceConsumer(workerMap, data);
FederationRequest req = fsmrc.discover(node.getIpAddress());
// then start a "heart-beat" thread
startHeartBeatThread();
// consume the service
fsmrc.consume(req);
// get back the processed data
ArrayList<Serializable> results = fsmrc.getDataList();
for (Serializable result : results) resultList.add(result);
// stop the "heart-beat" thread
stopHeartBeatThread();
// and close the connections
req.closeIt();
} catch (FederationServiceDiscoveryFailed fe) {
System.err.println(
"Exception in Worker thread: " + fe.toString() + ", for node: " + node.toString());
fe.printStackTrace();
System.err.println("Will now try to use other free nodes...");
synchronized (MapReduceControllerFederationImpl.this.freeNodeList) {
// add to the end of the list
MapReduceControllerFederationImpl.this.freeNodeList.add(node);
System.out.println(MapReduceControllerFederationImpl.this.freeNodeList.size());
// and change to a new node from beginning of the list
// that is not the same as the current node, if none is
// found keep trying the same node
FederationNode newNode = null;
for (FederationNode fn : MapReduceControllerFederationImpl.this.freeNodeList) {
if (!fn.getIpAddress().equals(node.getIpAddress())) {
newNode = fn;
break;
} // end if
} // end for
if (newNode == null) {
node = MapReduceControllerFederationImpl.this.freeNodeList.get(0);
} else {
node = newNode;
} // end if
}
System.err.println("Will be using: " + node);
// there was some problem with processing
// this data, so save it for other nodes
pushBackTaskData(taskData);
} catch (Exception ex) {
System.err.println(
"Exception in Worker thread: " + ex.toString() + ", for node: " + node.toString());
ex.printStackTrace();
// there was some problem with processing
// this data, so save it for other nodes
pushBackTaskData(taskData);
try {
// sleep for quite some time
sleep(10000);
} catch (InterruptedException ignored) {
}
} // end of try .. catch block
taskData = getNextTaskData();
} // end while
// if we are done we add our selfs in the free node list
// so as to make us available at a later stage, if some node
// breaks down
synchronized (MapReduceControllerFederationImpl.this.freeNodeList) {
MapReduceControllerFederationImpl.this.freeNodeList.add(node);
}
}