Programming 9. Design a Work Hours Calculator using Two-Dimensional Arrays

In this project, we are to design a Java program with which we can analyze hours worked by employees in a week. The program is a command line application. A user can request an analysis of the hours worked stored in a file based on the command line arguments.

File Structure

An input file to the file records the hours worked in a week. It is assumed that the organization has no more than 100 employees.

The structure of an input file is as follows:

  1. Each line is a record.
  2. The file begins with a header record.
  3. After the header, the file contain a list of employee records, each record consists of the employee ID, and the hours worked each day in the week.

The following is an example of the input file:

     ID Sun Mon Tue Wed Thu Fri Sat
N000001   8   4   5   6   4   5   4
N000002  10   4   9   5   5  10   4
N000003   9  10   6   8   6  10   7
N000004   8   4   1   9   1   8   2
N000005   8   6   5   9   6   6   6

Functionalities

The program has three functionalities.

Compute Hours Worked for Each Employee

When a user provides GetWeeklyHours, the path to an input file, and the path to an output file on the command line, the program shall

  1. load the data from the input file to arrays, a single-dimensional array for employee IDs and a two-dimensional array for hours worked daily by each employee in the week;
  2. compute the total hours worked in the week for each employee,
  3. and save the results to the output file that should be formatted similar to the input file except with an additional column for the total hours worked.

The following is a running example:

java WorkHoursCalculator GetWeeklyHours hours.txt weekly.txt
Wrote weekly.txt

where the content of the output file weekly.txt is as follows:

     ID Sun Mon Tue Wed Thu Fri Sat Total
N000001   8   4   5   6   4   5   4    36
N000002  10   4   9   5   5  10   4    47
N000003   9  10   6   8   6  10   7    56
N000004   8   4   1   9   1   8   2    33
N000005   8   6   5   9   6   6   6    46

which also exhibits the format of the output file.

Compute Daily Hours Worked

This functionality is to compute total hours worked by all employees daily. To request this functionality, the user shall enter GetDailyHours, the path to an input file, and the path to an output file as the command line arguments. The program shall

  1. load the data from the input file to arrays, a single-dimensional array for employee IDs and a two-dimensional array for hours worked daily by each employee in the week;
  2. compute the total hours worked in each day by all employees in the week;
  3. and save the results to the output file that should be formatted similar to the input file except with the last line as the total hours worked daily.

The following is a running example:

$ java WorkHoursCalculator GetDailyHours hours.txt daily.txt
Wrote daily.txt

where the content of the output file daily.txt is as follows:

     ID Sun Mon Tue Wed Thu Fri Sat
N000001   8   4   5   6   4   5   4
N000002  10   4   9   5   5  10   4
N000003   9  10   6   8   6  10   7
N000004   8   4   1   9   1   8   2
N000005   8   6   5   9   6   6   6
  Total  43  28  26  37  22  39  23

The example also shows what is required for the format of the output file.

Find Longest Work Day

To request this functionality, the user should give three command line arguments, GetLongestDay, the path to an input file, and the path to an output file, and the program should locate the first longest day worked by an employee. The program shall

  1. load the data from the input file to arrays, a single-dimensional array for employee IDs and a two-dimensional array for hours worked daily by each employee in the week;
  2. find the first occurrences of the longest work hours in a day by an employee;
  3. and save the results to the output file whose content is exhibited in the running example below.
$ java WorkHoursCalculator GetLongestDay hours.txt longest.txt
Wrote longest.txt

The output file longest.txt has the following content:

Longest Day Worked in the Week
 Employee ID: N000002
Hours worked: 10
         Day: Sunday

In the input file hours.txt, the longest hours worked in a day is 10 hours. Several employees worked 10 hours in several days. The program should always save the first occurrence to the file.

Divide-and-Conquer Strategy.

Although no sub-exercises given for this project, you should follow the divide-and-conquer strategy by designing the following methods:

public static int loadHours(String inFilePath, String[] ids, int[][] hours) throws FileNotFoundException

The method should be designed and used as follows. Since it is assumed that the organization has no more than 100 employees, you should create two arrays for employee IDs and hours worked. The arrays should be large enough to hold all data in the input file. The method should skip the header, read the employee IDs, and the hours worked to the two arrays. However, since the arrays may be bigger than actual records in the input file, the method should return an integer indicating the number of records read into the arrays. To process the arrays for the requested functionalities, you should use the return value to determine how many records there are in the arrays, which is the design purpose of the return value.

There are a variety of ways to read the data for an employee. If you wish to read the data one line at a time and wish to split the line into multiple parts, you should specify the delimiter as \\s+. Here, \\s+ defines the pattern of the String that separates the fields in the line, i.e., Strings consists of 1 or more spaces – \\s means white space character and + means the white space character repeats 1 or more times. However, you should use the way with which you are most comfortable.

public static int[] computeWeeklyHours(int size, int[][] hours)

This method is to compute total hours worked in the week by each employee. The hours should be returned as a single-dimensional array. Parameter size indicates the number of records in the arrays since some array elements may be unused due to the design of the loadHours method.

public static void saveWeeklyHours(int size, String[] ids, int[][] hours, int[] weeklyHours, String outFilePath) throws FileNotFoundException

Method saveWeeklyHours is to save the total hours worked in the week by each employee to the output file. Parameter size indicates the number of records in the arrays since some array elements may be unused due to the design of the loadHours method.

public static int[] computeDailyHours(int size, int[][] hours)

The computeDailyHours method computes the total hours worked in a day by all employees in the week. As before, parameter size indicates the number of records in the arrays since some array elements may be unused due to the design of the loadHours method. The total hours worked each week day is returned in a single-dimensional array.

public static void saveDailyHours(int size, String[] ids, int[][] hours, int[] dailyHours, String outFilePath) throws FileNotFoundException

This method save the total hours worked in a day by all employees in the week to the output file. Parameter size indicates the number of records in the arrays since some array elements may be unused due to the design of the loadHours method.

public static int[] getLongestDay(int size, int[][] hours)

Method getLongestDay is to determine the longest hours an employee worked in a day. The definition of parameter size is the same as before. The return value is an array of size 2. The array stores the array index of the two-dimensional array hours.

public static void saveLongestDay(String[] ids, int[][] hours, int[] longHourIndex, String outFilePath) throws FileNotFoundException

Method saveLongestDay saves the longest day data to the output file.