public List<LineChart> LineChartGen(String filePath, String dataType, List<String> columns, List<String> columnNames)
			throws IllegalArgumentException {
		// TODO Auto-generated method stub
		//Read data from hdfs
		List<String> results = readAllData(filePath,true); //Only read limited line data(if the data length over max length)
		List<LineChart> lineCharts = new ArrayList<LineChart>();
		for(String  selectedCol : columnNames)
		{
			LineChart lineChart =  singleLineGen(results, dataType, columns, selectedCol);
			if(lineChart == null)
				continue;
			else
				lineCharts.add(lineChart);
		}
		return lineCharts;
	}
public List<LineChart> LineChartGen(String filePath, String dataType, List<String> columns, List<String> columnNames)
			throws IllegalArgumentException {
	
	
		List<String> results = readAllData(filePath,true);
		List<LineChart> lineCharts = new ArrayList<LineChart>();
		for(String  selectedCol : columnNames)
		{
			LineChart lineChart =  singleLineGen(results, dataType, columns, selectedCol);
			if(lineChart == null)
				continue;
			else
				lineCharts.add(lineChart);
		}
		return lineCharts;
	}
public list<linechart> linechartgen(string filepath, string datatype, list<string> columns, list<string> columnnames) throws illegalargumentexception { list<string> results = readalldata(filepath,true); list<linechart> linecharts = new arraylist<linechart>(); for(string selectedcol : columnnames) { linechart linechart = singlelinegen(results, datatype, columns, selectedcol); if(linechart == null) continue; else linecharts.add(linechart); } return linecharts; }