Delivering Streaming Metrics - Real-Time Analytics - page 345

view.data({values:values}).update();
});
});
});
In this code, the dynamic data feature of Vega is also used. This method of
the view object takes an object with keys that correspond to tables defined
in the specification. The value of those keys overrides the corresponding
values key in the table definition of the view object. The end results are
charts like the examples in Figure 7.11 and implemented in dashboard/
public/javascripts/vega.js .
Figure 7.11
Mobile Streaming Applications
More and more of the world's application are becoming mobile in one sense
or another. Streaming data applications are no exception to this trend,
though they tend to be more useful on the larger tablet formats than the
smaller phone formats.
The infrastructure developed in this chapter has actually been developed
with mobile environments. For data transfer, the biggest killer of battery
life is applications that heavily use Wi-Fi or cellular radio activity. Polling
approaches seem to exercise the radios pretty heavily. SSEs and
WebSockets, empirically, appear to have relatively little effect on battery
life. In addition, both protocols automatically reconnect, making them good
choicesfortherelativelyunsureenvironmentthatismobilecommunication.