Get Futures' IDs in Java

Question

I have the following code:

for (int i = 0; i < nComp; i++) {
    Callable<Long> worker = new WSCaller(compConns[i]);
    col.add(worker);
}
List<Future<Long>> results=null;
results = executor.invokeAll(col, timeout, TimeUnit.SECONDS);

for (Future<Long> future : results) {
    if ( !future.isDone() ) {
        // here I need to know which future timed-out ...               
    }
}

As pointed out in the code ... How can I know which Future timed-out ?

Thanks

possible duplicate of [Is there a way to access an iteration-counter in Java's for-each loop?](http://stackoverflow.com/questions/477550/is-there-a-way-to-access-an-iteration-counter-in-javas-for-each-loop) — Brian Roach, Apr 15 '11 at 18:48

score 0 · Answer 1 · edited May 23 '17 at 09:58

0

see the solution here

you have to implement your own counter to know what index your are up to.

edited May 23 '17 at 09:58

Community

1
1

answered Apr 15 '11 at 18:42

Naftali

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score 0 · Answer 2 · answered Apr 15 '11 at 18:53

The futures are returned in the same order as the submitted callables, so there is a one to one correspondence between the indices in the callables list and futures list.

You can either use a traditional for loop,

for (int i=0; i<results.size(); i++) {
   Future<Long> future = results.get(i);
   Callable<Long> callable = col.get(i);
}

or maintain an index,

int index = 0;
for (Future<Long> f: results) {
   Callable<Long> c = col.get(index++);
}

Get Futures' IDs in Java

2 Answers2