/**
* Executes example.
*
* @param args Command line arguments, none required.
* @throws GridException If example execution failed.
*/
public static void main(String[] args) throws Exception {
Timer timer = new Timer("priceBars");
// Start grid.
final Grid g = GridGain.start("examples/config/example-streamer.xml");
System.out.println();
System.out.println(">>> Streaming price bars example started.");
try {
TimerTask task = scheduleQuery(g, timer);
streamData(g);
// Force one more run to get final results.
task.run();
timer.cancel();
// Reset all streamers on all nodes to make sure that
// consecutive executions start from scratch.
g.compute()
.broadcast(
new Runnable() {
@Override
public void run() {
if (!ExamplesUtils.hasStreamer(g, "priceBars"))
System.err.println(
"Default streamer not found (is example-streamer.xml "
+ "configuration used on all nodes?)");
else {
GridStreamer streamer = g.streamer("priceBars");
System.out.println("Clearing bars from streamer.");
streamer.reset();
}
}
})
.get();
} finally {
GridGain.stop(true);
}
}
/**
* Schedules the query to periodically output built bars to the console.
*
* @param g Grid.
* @param timer Timer.
* @return Scheduled task.
*/
private static TimerTask scheduleQuery(final Grid g, Timer timer) {
TimerTask task =
new TimerTask() {
@Override
public void run() {
final GridStreamer streamer = g.streamer("priceBars");
try {
Collection<Bar> bars =
streamer
.context()
.reduce(
// This closure will execute on remote nodes.
new GridClosure<GridStreamerContext, Collection<Bar>>() {
@Override
public Collection<Bar> apply(GridStreamerContext ctx) {
Collection<Bar> values = ctx.<String, Bar>localSpace().values();
Collection<Bar> res = new ArrayList<>(values.size());
for (Bar bar : values) res.add(bar.copy());
return res;
}
},
// The reducer will always execute locally, on the same node
// that submitted the query.
new GridReducer<Collection<Bar>, Collection<Bar>>() {
private final Collection<Bar> res = new ArrayList<>();
@Override
public boolean collect(@Nullable Collection<Bar> col) {
res.addAll(col);
return true;
}
@Override
public Collection<Bar> reduce() {
return res;
}
});
for (Bar bar : bars) System.out.println(bar.toString());
System.out.println("-----------------");
} catch (GridException e) {
e.printStackTrace();
}
}
};
timer.schedule(task, 2000, 2000);
return task;
}