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Renders bar and line charts as PNG images using JFreeChart, and builds regression-based forecasts and anomaly detectors from time series data. Registered as the chartManager service and reached from JS via services.chartManager. Use newChartBuilder() to configure and render a chart as PNG bytes, or newRegressionBuilder() to accumulate date-value observations ahead of forecasting or anomaly detection.
Group: Managers
Methods
newChartBuilder()
Returns: ChartBuilder
Creates a new, empty chart builder for configuring and rendering a chart.
renderChart(String specJson)
Returns: byte[]
Renders a chart from a declarative JSON specification, as PNG bytes. The builder above is the API to use from Java. This one exists for callers that are handed a whole chart to draw rather than building one up - an agent tool, most obviously, where the specification arrives as JSON already and every builder call in between is a chance for a number to be coerced into something else on its way across Nashorn.
| Parameter | Description |
|---|---|
specJson | {@code {chartType, title, xLabel, yLabel, width, height, categories:[..], series:[{name, values:[..]}]}}. chartType is one of bar, horizontalBar, stackedBar, line or pie, and defaults to bar; only categories and series are required |
newRegressionBuilder()
Returns: RegressionBuilder
Creates a new regression builder named "default", for accumulating date-value observations ahead of forecasting or anomaly detection.
newRegressionBuilder(String name)
Returns: RegressionBuilder
Creates a new, named regression builder for accumulating date-value observations ahead of forecasting or anomaly detection.
| Parameter | Description |
|---|---|
name | identifies the resulting model in log messages; has no effect on the data |
toBase64(byte[] data)
Returns: String
Encodes the given bytes as a base64 string, for embedding a chart's image bytes directly in HTML or JSON.
| Parameter | Description |
|---|---|
data | the bytes to encode |
buildBarChart(ChartBuilder b)
Returns: byte[]
Renders the data points added to the given builder as a JFreeChart bar chart and returns the PNG image bytes. Only CategoryDataPoint entries in the builder's data are plotted; other data point types are ignored.
| Parameter | Description |
|---|---|
b | the builder holding the chart's title, axis labels, dimensions and data |
buildXYLineChart(ChartBuilder b)
Returns: byte[]
Renders the data points added to the given builder as a JFreeChart XY line chart and returns the PNG image bytes. Only XYDataPoint entries in the builder's data are plotted; other data point types are ignored. If the builder's date range flag is set, the x-axis is rendered with date-formatted tick units.
| Parameter | Description |
|---|---|
b | the builder holding the chart's title, axis labels, dimensions and data |
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