How to Troubleshoot Dynamic JFreeChart Series Updates Without a Time-Based Axis?

Troubleshooting Random Errors when Changing Series Using JFreeChart

Introduction
This discussion addresses issues encountered when attempting to dynamically update a JFreeChart dataset by adding and removing series. The goal is to visualize changing data points over time without relying on a time-based X-axis or using the DynamicTimeSeriesCollection.

Issues and Resolution

The provided code attempts to update the dataset by repeatedly adding and removing a series, but this approach is incorrect. Instead, the dataset should be updated within the process() method of a SwingWorker.

Additionally, to create a chart with a domain based on iteration count rather than time, use a NumberAxis instead of a DateAxis.

Example Code

The following code snippet demonstrates how to track the progress of a computation using a line chart:

private XYSeries series = new XYSeries("Result");
…
@Override
protected void process(List<double> chunks) {
    for (double d : chunks) {
        label.setText(df.format(d));
        series.add(++n, d);
    }
}</double>

The graph will automatically update as the computation progresses.

Additional Considerations

• Correct Synchronization: The dataset should only be modified from the process() method of a SwingWorker to ensure thread safety.
• NumberAxis: Use a NumberAxis for both the domain and range when using a line chart with a non-time-based X-axis.
• Shape Visibility: Set the shape visibility of the renderer to true to display data points as circles on the line.
• Progress Bar: Use a progress bar to provide visual feedback about the computation's progress.

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