Search code examples
javajfreechart

Chart with Fixed Second Time Interval on X Axis

I am trying to have a chart that is having an x chart with interval values from 0 to 120. The data will be updated every second. The type of chart is exactly like CPU Chart in windows task manager: this

I have checked the topics:

  1. Random errors when changing series using JFreeChart
  2. JFreechart series movement with fixed x-axis
  3. JFreeChart - How to show real-time on the X-Axis of a TimeSeries chart

Even though the answers to those topics were really helpful for me the understand yet I could not reach what I want to do.

Thank you in advance.

Solution

  • Since I had no answer, in the mean time I solved my problem like following. Though, I think that there is, -there should be-, easier way to do this.Since I was limited on time I came up with this solution. If you have anything better, or something you see to be improved, please share so.

    I add to my LinkedList until it gets as big as I want.(120 in this case). After that It removes the last entry, adds to the beginning. This method is called every second by another thread.

       private final LinkedList<XYDataItem> countHistory = new LinkedList<>();
   private static final int MAX_RANGE_IN_X_AXIS_FOR_XY_CHART = 121;
enter code here
   public void getDataAndRefresh( final DefaultTableXYDataset xySeriesCollection)
   {
      synchronized ( this.adsbItemMap )
      {
         int count = 0;

     if ( xySeriesCollection.getSeries( 0 ) != null )
     {
        final XYSeries xySeries = xySeriesCollection.getSeries( 0 );
        try
        {

           if ( this.counter == MAX_RANGE_IN_X_AXIS_FOR_XY_CHART )
           {
              xySeries.getItems().forEach( item -> {
                 final XYDataItem xyItem = ( XYDataItem ) item;
                 this.countHistory.addLast(
                       new XYDataItem( xyItem.getXValue()+1,xyItem.getYValue()));
              } );
              //xySeries.clear();
              this.countHistory.pollLast();
              this.countHistory.addFirst( new XYDataItem( 0, count ) );
              this.countHistory.forEach( xySeries::addOrUpdate );
              this.countHistory.clear();
           }
           else
           {
              xySeries.getItems().forEach( item -> {
                 final XYDataItem xyItem = ( XYDataItem ) item;
                 this.countHistory.addLast(
                       new XYDataItem( xyItem.getXValue() + 1, xyItem.getYValue() ) );
              } );
              final XYDataItem countItem = new XYDataItem( 0, count );
              this.countHistory.addFirst( countItem );
              this.countHistory.forEach( xySeries::addOrUpdate );
              this.countHistory.clear();
              this.counter++;
           }
        }
        catch ( final Exception e )
        {
           LOG.warn( "Something went wrong.", e );
        }
     }
     //clear
     total.setValue( count );
     this.adsbItemMap.clear();
  }
}