Notes

Code

There are two seprate files

Stundent class that implements Comprable interface

package guistudentsort;
public class Student implements Comparable<Student>
{
private int id;
private String name;
/**
* @param id
* @param name
*/
public Student(int id, String name) {
this.id = id;
this.name = name;
}
/**
* @return the id
*/
public int getId() {
return id;
}
/**
* @param id the id to set
*/
public void setId(int id) {
this.id = id;
}
/**
* @return the name
*/
public String getName() {
return name;
}
/**
* @param name the name to set
*/
public void setName(String name) {
this.name = name;
}

@Override
public String toString() {
return id + "t" + name+"n";
}

@Override
public int compareTo(Student o) {
if(id<o.getId())
return -1;
else if(id>o.getId())
return 1;
return 0;
}
}

For GUI

/*
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*/
package guistudentsort;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileWriter;
import java.io.IOException;
import java.io.PrintWriter;
import javafx.application.Application;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.layout.GridPane;
import javafx.scene.layout.StackPane;
import javafx.stage.Stage;
import java.util.*;
import java.util.logging.Level;
import java.util.logging.Logger;
import javafx.scene.control.Alert;
import javafx.scene.control.Alert.AlertType;
/**
*
* @author JOSEE
*/
public class GUIStudentSort extends Application {
private Button btnLoad = new Button("Load");
private Button btnSort = new Button("Sort");
private Button btnSave = new Button("Save");
@Override
public void start(Stage primaryStage) {

ArrayList<Student>students=new ArrayList<>();
btnLoad.setMaxSize(100, 200);
btnSort.setMaxSize(100, 200);
btnSave.setMaxSize(100, 200);
GridPane gridPane = new GridPane();
gridPane.setHgap(5);
gridPane.setVgap(20);
Alert a = new Alert(AlertType.NONE);
gridPane.add(btnLoad,0,0);
gridPane.add(btnSort,0,1);
gridPane.add(btnSave,0,2);
gridPane.setAlignment(Pos.CENTER);

btnLoad.setOnAction((event) -> {
Scanner scan;
try
{
scan = new Scanner(new File("unsortedStudents.txt"));
int id;
String name;
while(scan.hasNext())
{
students.add(new Student(scan.nextInt(),scan.next()));
}
scan.close();
a.setAlertType(AlertType.CONFIRMATION);
a.setContentText("All student data have been recorded.");
a.show();
}
catch (FileNotFoundException ex) {
a.setAlertType(AlertType.WARNING);
a.setContentText("unsortedStudents.txt file not found.");
a.show();
}

});

btnSort.setOnAction((event) -> {

if(students.isEmpty())
{
a.setAlertType(AlertType.WARNING);
a.setContentText("List is empty. Please load the student data..");
a.show();
}
else
{
Collections.sort(students);
a.setAlertType(AlertType.CONFIRMATION);
a.setContentText("Student data has been sorted by student id.");
a.show();
}
});
btnSave.setOnAction((event) -> {

if(students.isEmpty())
{
a.setAlertType(AlertType.WARNING);
a.setContentText("List is empty. Please load the student data..");
a.show();
}
else
{
FileWriter fileWriter;
try {
fileWriter = new FileWriter("StudentsSortedById.txt");
PrintWriter printWriter = new PrintWriter(fileWriter);
for(Student s:students)
printWriter.write(s.toString());
printWriter.close();
fileWriter.close();
a.setAlertType(AlertType.CONFIRMATION);
a.setContentText("Student data saved to "StudentsSortedById.txt" successfully.");
a.show();
}
catch (IOException ex)
{
a.setAlertType(AlertType.WARNING);
a.setContentText("unsortedStudents.txt file not found.");
a.show();
}


}
});
Scene scene = new Scene(gridPane, 300, 150);
primaryStage.setTitle("Investment Calculator"); // Set title
primaryStage.setScene(scene); // Place the scene in the stage
primaryStage.show(); // Display the stage
}

/**
* @param args the command line arguments
*/
public static void main(String[] args) {
launch(args);
}

}