private ArrayList dataGenerator() { 
  double series1[] = new double[5];  
      for(int i=0; i<series1.length; i++) 
       series1[i] = (i*10) + 10; // a linear  
       series containing 10,20,30,40,50 
       
      double series2[] = new double[9];  
      series2[0] = 20; series2[1] = 150; series2[2] = 5; 
      series2[3] = 90; series2[4] = 35;  series2[5] = 20; 
                            series2[6] = 150; series2[7] = 5; series2[8] = 45; 
       
      double series3[] = new double[7];  
      for(int i=0; i<series3.length; i++) 
       series3[i] = (i*20) + 15; 
      
      seriesData.add(series1); 
      seriesData.add(series2); 
      seriesData.add(series3);  
                 return seriesData; 
 }