SortSalaries.java

package test;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.LineNumberReader;
import java.util.Collections;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;

public class JavaTest
{
    public static void main(String[] args)
    {
        List salaries = readSalaries( "input.txt" );      
        Collections.sort( salaries );
        writeSalaries( salaries, "output.txt" );
    }

    private static List readSalaries(String fileName)
    {
        LineNumberReader lineReader = openInputFile(fileName);;
        String line;
        List salaries = new LinkedList();
        while ( (line = readLine(lineReader,fileName)) != null)
        {
            salaries.add(getSalary(split(line)));
        }
        return salaries;
    }

    private static String readLine(LineNumberReader lineReader, String fileName) 
    {
        String line = null;
        try
        {
            line = lineReader.readLine();
        } 
        catch (IOException e)
        {
            handleIOException("IOException wile reading from " + fileName + ".", e);
        }
        return line;
    }

    private static LineNumberReader openInputFile(String fileName)
    {
        File inputFile = new File( fileName);       
        FileReader fileReader = null;
        try
        {
            fileReader = new FileReader(inputFile);
        } 
        catch (FileNotFoundException e)
        {
            handleIOException("IOException wile opening " + fileName + ".", e);
        }        
        return new LineNumberReader(fileReader);
    }

    private static String getSalary(String[] records)
    {
        return records[2];
    }

    private static String[] split(String line)
    {
        return line.split(",");
    }

    private static void writeSalaries(List salaries, String fileName)
    {
        FileWriter outputFileWriter = open(fileName);      
        write("Salaries - Java \n", outputFileWriter, fileName);
        for (Iterator iterator = salaries.iterator(); iterator.hasNext();)
        {
            String salary = (String) iterator.next();
            write(salary, outputFileWriter, fileName);
        }            
        close(outputFileWriter, fileName);           
    }

    private static void write(String salary, FileWriter outputFileWriter, String fileName)
    {
        try
        {
            outputFileWriter.write(salary + "\n");
        }
        catch (IOException e)
        {
            handleIOException("IOException wile writing to " + fileName + ".", e);
        }
    }

    private static FileWriter open(String fileName)
    {
        FileWriter outputFileWriter = null;
        try
        {
            outputFileWriter = new FileWriter( new File( fileName ) );
        } 
        catch (IOException e)
        {
            handleIOException("IOException wile opening " + fileName + ".", e);
        }
        return outputFileWriter;
    }

    private static void close(FileWriter outputFileWriter, String fileName)
    {
        try
        {
            outputFileWriter.close();
        } 
        catch (IOException e)
        {
            handleIOException("IOException wile closing " + fileName + ".", e);
        }
    }

    private static void handleIOException(String message, IOException e)
    {
        e.printStackTrace();
        throw new RuntimeException(message);
    }
}