public void start(long newDataWindowEndTimeMillis) {
    Utils.checkState(!started, "Already started");
    Utils.checkState(!stopped, "Already stopped");
    dataProvider.start(newDataWindowEndTimeMillis);
    started = true;
  }
public void start(long newDataWindowEndTimeMillis) {
    Utils.checkState(!started, "Already started");
    Utils.checkState(!stopped, "Already stopped");
    dataProvider.start(newDataWindowEndTimeMillis);
    started = true;
  }
public void start ( long newDataWindowEndTimeMillis ) { Utils . checkState ( ! started , "Already started" ) ; Utils . checkState ( ! stopped , "Already stopped" ) ; dataProvider . start ( newDataWindowEndTimeMillis ) ; started = true ; }
Starts the Aggregators instance.

@param newDataWindowEndTimeMillis ending time of the new DataWindow.
Starts the Aggregators instance .