/**
* Get the archive entries in classpath as an array of Path
*
* @param conf Configuration that contains the classpath setting
*/
public static Path[] getArchiveClassPaths(Configuration conf) {
String classpath = conf.get("mapred.job.classpath.archives");
if (classpath == null) return null;
ArrayList list =
Collections.list(new StringTokenizer(classpath, System.getProperty("path.separator")));
Path[] paths = new Path[list.size()];
for (int i = 0; i < list.size(); i++) {
paths[i] = new Path((String) list.get(i));
}
return paths;
}
private float mean(ArrayList<Integer> l) {
int t = l.size();
Integer sum = new Integer(0);
for (Integer i : l) {
sum += i;
}
return ((float) sum) / t;
}
private float standard_deviation(ArrayList<Integer> l) {
int t = l.size();
float ans = 0, mn = this.mean(l);
for (Integer i : l) {
ans += (i - mn) * (i - mn);
}
return (float) Math.sqrt(ans / (t - 1));
}
/**
* A TaskTracker wants to know the physical locations of completed, but not yet closed, tasks.
* This exists so the reduce task thread can locate map task outputs.
*/
public synchronized MapOutputLocation[] locateMapOutputs(
String taskId, String[][] mapTasksNeeded) {
ArrayList v = new ArrayList();
for (int i = 0; i < mapTasksNeeded.length; i++) {
for (int j = 0; j < mapTasksNeeded[i].length; j++) {
TaskInProgress tip = (TaskInProgress) taskidToTIPMap.get(mapTasksNeeded[i][j]);
if (tip != null && tip.isComplete(mapTasksNeeded[i][j])) {
String trackerId = (String) taskidToTrackerMap.get(mapTasksNeeded[i][j]);
TaskTrackerStatus tracker;
synchronized (taskTrackers) {
tracker = (TaskTrackerStatus) taskTrackers.get(trackerId);
}
v.add(new MapOutputLocation(mapTasksNeeded[i][j], tracker.getHost(), tracker.getPort()));
break;
}
}
}
// randomly shuffle results to load-balance map output requests
Collections.shuffle(v);
return (MapOutputLocation[]) v.toArray(new MapOutputLocation[v.size()]);
}
private int median(ArrayList<Integer> l) {
Collections.sort(l);
int t = l.size();
return l.get(t / 2);
}