You have to use comment function to describe what each line does import java.io.BufferedReader; import java.io.FileNotFoundException; import java.io.FileReader; import java.io.IOException; import java.util.ArrayList; import java.util.Arrays; import java.util.List; public class PreferenceData { private final List students; private final List projects; private int[][] preferences; private static enum ReadState { STUDENT_MODE, PROJECT_MODE, PREFERENCE_MODE, UNKNOWN; }; public PreferenceData() { super(); this.students = new ArrayList(); this.projects = new ArrayList(); } public void addStudent(Student s) { this.students.add(s); } public void addStudent(String s) { this.addStudent(Student.createStudent(s)); } public void addProject(Project p) { this.projects.add(p); } public void addProject(String p) { this.addProject(Project.createProject(p)); } public void createPreferenceMatrix() { this.preferences = new int[this.students.size()][this.projects.size()]; } public void setPreference(Student s, Project p, int preference) { this.preferences[this.students.indexOf(s)][this.projects.indexOf(p)] = preference; } public void setPreference(int row, int column, int preference) { this.preferences[row][column] = preference; } public void setPreferenceRow(int row, String[] prefValues) { for (int j = 0; j < prefValues.length; j++) { this.preferences[row][j] = Integer.parseInt(prefValues[j]); } } public List getStudents() { return students; } public List getProjects() { return projects; } public int[][] getPreferences() { return preferences; } @Override public String toString() { return "PreferenceData [students=" + students + ", projects=" + projects + ", preferences=" + Arrays.toString(preferences) + "]"; } static PreferenceData readData(String inputFile) { PreferenceData prefs = new PreferenceData(); try(BufferedReader reader = new BufferedReader(new FileReader(inputFile))) { ReadState state = ReadState.UNKNOWN; int row = 0; while (reader.ready()) { String line = reader.readLine(); switch (line.trim()) { case "Students:": state = ReadState.STUDENT_MODE; break; case "Projects:": state = ReadState.PROJECT_MODE; break; case "Preferences:": prefs.createPreferenceMatrix(); state = ReadState.PREFERENCE_MODE; break; default: switch (state) { case STUDENT_MODE: prefs.addStudent(line); break; case PROJECT_MODE: prefs.addProject(line); break; case PREFERENCE_MODE: prefs.setPreferenceRow(row, line.split(",")); row++; break; default: throw new PreferenceFormatException(line); } } } reader.close(); } catch (FileNotFoundException e) { System.err.println("Error opening preferences file. File does not exist as specified."); e.printStackTrace(); } catch (IOException e) { System.err.println("Error reading from file."); e.printStackTrace(); } catch (PreferenceFormatException e) { System.err.println("Preference file in incorrect format. I can't tell which section I'm in."); System.err.println("Line being read: " + e.getCurrentLine()); e.printStackTrace(); } return prefs; } public int getPreference(int i, int j) { return this.preferences[i][j]; } public int numStudents() { return this.students.size(); } public int numProjects() { return this.projects.size(); } }
You have to use comment function to describe what each line does
import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
public class PreferenceData {
private final List<Student> students;
private final List<Project> projects;
private int[][] preferences;
private static enum ReadState {
STUDENT_MODE, PROJECT_MODE, PREFERENCE_MODE, UNKNOWN;
};
public PreferenceData() {
super();
this.students = new ArrayList<Student>();
this.projects = new ArrayList<Project>();
}
public void addStudent(Student s) {
this.students.add(s);
}
public void addStudent(String s) {
this.addStudent(Student.createStudent(s));
}
public void addProject(Project p) {
this.projects.add(p);
}
public void addProject(String p) {
this.addProject(Project.createProject(p));
}
public void createPreferenceMatrix() {
this.preferences = new int[this.students.size()][this.projects.size()];
}
public void setPreference(Student s, Project p, int preference) {
this.preferences[this.students.indexOf(s)][this.projects.indexOf(p)] = preference;
}
public void setPreference(int row, int column, int preference) {
this.preferences[row][column] = preference;
}
public void setPreferenceRow(int row, String[] prefValues) {
for (int j = 0; j < prefValues.length; j++) {
this.preferences[row][j] = Integer.parseInt(prefValues[j]);
}
}
public List<Student> getStudents() {
return students;
}
public List<Project> getProjects() {
return projects;
}
public int[][] getPreferences() {
return preferences;
}
@Override
public String toString() {
return "PreferenceData [students=" + students + ", projects=" + projects + ", preferences="
+ Arrays.toString(preferences) + "]";
}
static PreferenceData readData(String inputFile) {
PreferenceData prefs = new PreferenceData();
try(BufferedReader reader = new BufferedReader(new FileReader(inputFile))) {
ReadState state = ReadState.UNKNOWN;
int row = 0;
while (reader.ready()) {
String line = reader.readLine();
switch (line.trim()) {
case "Students:":
state = ReadState.STUDENT_MODE;
break;
case "Projects:":
state = ReadState.PROJECT_MODE;
break;
case "Preferences:":
prefs.createPreferenceMatrix();
state = ReadState.PREFERENCE_MODE;
break;
default:
switch (state) {
case STUDENT_MODE:
prefs.addStudent(line);
break;
case PROJECT_MODE:
prefs.addProject(line);
break;
case PREFERENCE_MODE:
prefs.setPreferenceRow(row, line.split(","));
row++;
break;
default:
throw new PreferenceFormatException(line);
}
}
}
reader.close();
} catch (FileNotFoundException e) {
System.err.println("Error opening preferences file. File does not exist as specified.");
e.printStackTrace();
} catch (IOException e) {
System.err.println("Error reading from file.");
e.printStackTrace();
} catch (PreferenceFormatException e) {
System.err.println("Preference file in incorrect format. I can't tell which section I'm in.");
System.err.println("Line being read: " + e.getCurrentLine());
e.printStackTrace();
}
return prefs;
}
public int getPreference(int i, int j) {
return this.preferences[i][j];
}
public int numStudents() {
return this.students.size();
}
public int numProjects() {
return this.projects.size();
}
}
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