CSVWriter.java

package waelti.statistics.export;

import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.util.List;

import waelti.statistics.queries.AbstractQuery;
import waelti.statistics.queries.ResultMatrix;

public class CSVWriter {
	
	private static String delimiter = ";";
	
	public static File write(AbstractQuery query, String file) throws IOException{
		return CSVWriter.write(query, new File(file));
	}
	
	/**
	 * Writes the data to a csv file with ';' as a delimiter and returns the file. If writing fails,
	 * null will be returned.
	 * 
	 * @throws IOException
	 */
	public static File write(AbstractQuery query, File file) throws IOException{
		ResultMatrix matrix = query.getMatrix();
		return CSVWriter.writer(matrix, file);
	}
	
	public static File writer(ResultMatrix matrix, File file) throws IOException{
		
		FileWriter writer = new FileWriter(file);
		
		CSVWriter.writeHeading(writer, matrix.getHeadings());
		
		for (Object[] objects : matrix) {
			CSVWriter.writeRow(writer, objects);
		}
		
		writer.close();
		return file;
	}
	
	private static void writeHeading(FileWriter writer, List<String> headings) throws IOException{
		Object[] objects = headings.toArray();
		CSVWriter.writeRow(writer, objects);
	}
	
	private static void writeRow(FileWriter writer, Object[] objects) throws IOException{
		StringBuffer buf = new StringBuffer();
		for (Object obj : objects) {
			buf.append(obj.toString());
			buf.append(CSVWriter.delimiter);
		}
		buf.deleteCharAt(buf.length() - 1); // last delimiter not needed
		buf.append("\n");
		writer.write(buf.toString());
	}
	
}