import java.io.BufferedReader;
import java.io.File;
import java.io.FileOutputStream;
import java.io.FileReader;
import java.io.IOException;
import java.util.ArrayList;

import org.apache.poi.ss.usermodel.CellStyle;
import org.apache.poi.xssf.streaming.SXSSFCell;
import org.apache.poi.xssf.streaming.SXSSFRow;
import org.apache.poi.xssf.streaming.SXSSFSheet;
import org.apache.poi.xssf.streaming.SXSSFWorkbook;
import org.apache.poi.xssf.usermodel.XSSFCellStyle;

public class Sample {
	public static void main(String[] args) throws IOException{

		createSampleExcelDocumentFromFile();
		checkRowFormatting();
	}

	public static void createSampleExcelDocumentFromFile() throws IOException{
		int rowCount = 0;
		ArrayList<String> rowList = new ArrayList<String>();


		rowList = getRowInputFromFile();

		//Create workbook and worksheet
		SXSSFWorkbook wb = new SXSSFWorkbook();
		SXSSFSheet worksheet = (SXSSFSheet) wb.createSheet("sample");

		System.out.println("Running...");
		//Loop through and add all values from array list
		for(int i=0; i<rowList.size(); i++){
			//Create new row
			SXSSFRow row = (SXSSFRow) worksheet.createRow(rowCount++);

			//Create cell style
			CellStyle style = wb.createCellStyle();
			style.setAlignment(XSSFCellStyle.ALIGN_RIGHT);

			//Create cell
			SXSSFCell cell = (SXSSFCell) row.createCell(0);

			//Set cell style
			cell.setCellStyle(style);

			//Set cell value
			if(rowList.get(i).matches("\\d+(\\.\\d{1,2})?")){
				double value = Double.parseDouble(rowList.get(i));
				cell.setCellValue(value);
			}
			else{
				cell.setCellValue(rowList.get(i));
			}

		}
		//add column width for appearance sake
		worksheet.setColumnWidth(0, 5000);
		
		// Write the output to a file		
		System.out.println("Writing...");
		FileOutputStream fileOut = new FileOutputStream("sample.xlsx");
		wb.write(fileOut);
		fileOut.close();
		
		System.out.println("Done");
	}
	
	public static ArrayList<String> getRowInputFromFile() throws IOException{
		File fileIn = new File("sample.txt");
		BufferedReader br = new BufferedReader(new FileReader(fileIn));

		String line = null;
		ArrayList<String> rowList = new ArrayList<String>();

		while ((line = br.readLine()) != null) {
			rowList.add(line);
		}
		br.close();
		return rowList;
	}
	
	public static void checkRowFormatting(){
		//Add code here
	}
}