What are helper objects in java?

Question

I come across few of the times called helper objects... can anybody elaborate what are those helper objects and why do we need them?

Answer 1

import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Scanner;

public class Helpers {
public static String getDate() {
    SimpleDateFormat dateFormat = new SimpleDateFormat("dd-MM-yyyy");
        return dateFormat.format(new Date());
    }

    public static boolean isTimeABeforeTimeB(String timeA, String timeB) {
        try {
            SimpleDateFormat dateFormat = new SimpleDateFormat("dd-MM-yyyy hh:mm aa");
            Date dA = dateFormat.parse(timeA);
            Date dB = dateFormat.parse(timeB);
            if (dA.getTime() < dB.getTime()) {
                return true;
            } else {
                return false;
            }
        } catch (Exception e) {
            //
        }
        return false;
    }

    public static String getDateAndTimeInput(String prompt) {
        Scanner input = new Scanner(System.in);
        String ans;
        SimpleDateFormat dateFormat = new SimpleDateFormat("dd-MM-yyyy hh:mm aa");
        dateFormat.setLenient(false);
        boolean dateValid;
        do {
            System.out.print(prompt);
            ans = input.nextLine();
            ans = ans.trim();
            dateValid = true;
            try {
                Date d = dateFormat.parse(ans);
            } catch (Exception e) {
                dateValid = false;
            }
        } while (!dateValid);
        return ans;
    }


    public static String getStringInput(String prompt) {
        Scanner input = new Scanner(System.in);
        String ans;

        do {
            System.out.print(prompt);
            ans = input.nextLine();
            ans = ans.trim();
        } while (ans.length() == 0);
        return ans;
    }

    public static double getDoubleInput(String prompt) {
        Scanner input = new Scanner(System.in);
        double ans = 0;
        boolean inputValid;
        do {
            System.out.print(prompt);
            String s = input.nextLine();
            //Convert string input to integer
            try {
                ans = Double.parseDouble(s);
                inputValid = true;
            } catch (Exception e) {
                 inputValid = false;
            }
        } while (!inputValid);
        return ans;
    }

    public static int getIntegerInput(String prompt) {
        Scanner input = new Scanner(System.in);
        int ans = 0;
        boolean inputValid;
        do {
            System.out.print(prompt);
            String s = input.nextLine();
            // Convert string input to integer
            try {
                ans = Integer.parseInt(s);
                inputValid = true;
            } catch (Exception e) {
                inputValid = false;
            }
        } while (!inputValid);
        return ans;
    }

    public static int getIntegerInput(String prompt, int lowerBound, int upperBound) {
        Scanner input = new Scanner(System.in);
        int ans = 0;
        boolean inputValid;
        do {
            System.out.print(prompt);
            String s = input.nextLine();
            // Convert string input to integer
            try {
                ans = Integer.parseInt(s);
                if (ans >= lowerBound && ans <= upperBound) {
                    inputValid = true;
                } else {
                     inputValid = false;
                }
            } catch (Exception e) {
                inputValid = false;
            }
       } while (!inputValid);
       return ans;
   }
}

that is an example of of a Helper Class. It contains method which of are common use of the other classes in the project.

Example if someone wants to enter an Integer number from a class hew ill have to type in this: String num = Helpers.getIntegerInput("input your number");

The prompt is the output that is show to the user. Other examples to input a String, double, date and time etc.