Creating Charts in JavaFX - JavaFX 8: A Definitive Guide to Building Desktop, Mobile, and Embedded Java Clients - page 359

Figure 8-6. The result of the naive implementation of the ScatterChart
Although the chart shows the required information, it is not very readable. We add a number of enhancements,
but first let's have a deeper look at the different parts of the code.
Similar to the PieChart example, we created a separate method for obtaining the data. One of the reasons for this
is that in real-world applications, it is unlikely to have static data. By isolating the data retrieval in a separate method,
it becomes easier to change the way data are obtained.
A single data point is defined by an instance of XYChart.Data<Integer , Double> , created with the constructor
XYChart.Data(Integer i, Double d) where the parameters have the following definitions.
i: Integer, representing a specific year (between 2011 and 2020)
d: Double, representing the hypothetical TIOBE index for the particular series in the year
specified by I
The local variables javaValue , cValue , and cppValue are used for keeping track of the scores for the different
programming languages. They are initialized with the real values from 2011. Each year, an individual score is
incremented or decremented by a random value between -2 and +2. Data points are stacked into a series. In our
examples, we have three series each containing 10 instances of XYChart.Data<Integer , Double> . Those series are of
type XYChart.Series<Integer, Double> .
The data entries are added to the respective series by calling
java.getData().add (...)
c.getData().add(...)
and
cpp.getData().add(...)
Finally, all series are added to the ObservableList<XYChart.Series<Integer, Double>>a nd returned.
The start() method of the application contains the functionality required for creating and rendering the
ScatterChart , and for populating it with the data obtained from the getChartData method.