Processing Streaming Data - Real-Time Analytics - page 172

PowerBolt()).shuffleGrouping("split");
builder.setBolt("return", new
ReturnResults()).shuffleGrouping("power");
The SplitBolt implementation splits the input comma-separated list into
two Double values. It also passes along the return-info element of the
tuple, which is used by ReturnResults to submit the result back to the
DRPC server:
public class SplitBolt extends BaseBasicBolt {
private static final long serialVersionUID =
-3681655596236684743L;
public void execute(Tuple input,
BasicOutputCollector collector) {
String[] p = input.getString(0).split(",");
collector.emit(
new Values(
Double. parseDouble (p[0]),
Double. parseDouble (p[1]),
input.getValue(1)
)
);
}
public void declareOutputFields(OutputFieldsDeclarer
declarer) {
declarer.declare( new
Fields("x","y","return-info"));
}
}
The PowerBolt implementation takes the x and y values and computes the
power function. It returns this value as a String as required by the DRPC
power and also makes sure to transfer the return-info object:
public class PowerBolt extends BaseBasicBolt {
private static final long serialVersionUID = 1L;
public void execute(Tuple input,
BasicOutputCollector collector) {
collector.emit(