Java Scanner Input Helpers

InputHelpers.java

/**
 * Created: 7/19/2019
 * Updated: 10/9/2020
 * Uploaded: 10/5/2020
 * Author: Jared Moore
 * Gist: https://gist.github.com/intelliapps-io/3d9e0773586927b910379ca542a179f8
 */

import java.util.Scanner;

interface StringValidator {
  boolean test(String input);
}

interface IntValidator {
  boolean test(int input);
}

interface DoubleValidator {
  boolean test(double input);
}

public class InputHelpers {
  public static void log(String msg) {
    System.out.println(msg);
  }

  /**
   * Get Integer Input
   * 
   * @param validator    lambda (input) -> boolean
   * @param errorMessage String
   * @return int
   */
  public static int getIntInput(IntValidator validator, String errorMessage) {
    Scanner keyboard = new Scanner(System.in);
    int parsedInput = 0;
    boolean inputValidated = false;
    do {
      String input = keyboard.nextLine();
      try {
        parsedInput = Integer.parseInt(input);
        if (validator.test(parsedInput))
          inputValidated = true;
        else
          throw new Exception("");
      } catch (Exception error) {
        log("\nError, \"" + input + "\" is invalid.\n" + errorMessage);
      }
    } while (!inputValidated);
    return parsedInput;
  }

  public static int getIntInput() {
    Scanner keyboard = new Scanner(System.in);
    int parsedInput = 0;
    boolean inputValidated = false;
    do {
      String input = keyboard.nextLine();
      try {
        parsedInput = Integer.parseInt(input);
        inputValidated = true;
      } catch (Exception error) {
        log("\nError, \"" + input + "\" is not an integer.\n");
      }
    } while (!inputValidated);
    return parsedInput;
  }

  /**
   * Get Double Input
   * 
   * @param validator    lambda (input) -> boolean
   * @param errorMessage String
   * @return double
   */
  public static double getDoubleInput(DoubleValidator validator, String errorMessage) {
    Scanner keyboard = new Scanner(System.in);
    double parsedInput = 0;
    boolean inputValidated = false;
    do {
      String input = keyboard.nextLine();
      try {
        parsedInput = Double.parseDouble(input);
        if (validator.test(parsedInput))
          inputValidated = true;
        else
          throw new Exception("");
      } catch (Exception error) {
        log("\nError, \"" + input + "\" is invalid.\n" + errorMessage);
      }
    } while (!inputValidated);
    return parsedInput;
  }

  public static double getDoubleInput() {
    Scanner keyboard = new Scanner(System.in);
    double parsedInput = 0;
    boolean inputValidated = false;
    do {
      String input = keyboard.nextLine();
      try {
        parsedInput = Double.parseDouble(input);
        inputValidated = true;
      } catch (Exception error) {
        log("\nError, \"" + input + "\" is not a number.\n");
      }
    } while (!inputValidated);
    return parsedInput;
  }

  /**
   * Get String Input
   * 
   * @param validator    lambda (input) -> boolean
   * @param errorMessage String
   * @return String
   */
  public static String getStringInput(StringValidator validator, String errorMessage) {
    Scanner keyboard = new Scanner(System.in);
    String parsedInput = "";
    boolean inputValidated = false;
    do {
      String input = keyboard.nextLine();
      try {
        if (validator.test(input)) {
          inputValidated = true;
          parsedInput = input;
        }
        else
          throw new Exception("");
      } catch (Exception error) {
        log("\nError, \"" + input + "\" is invalid.\n" + errorMessage);
      }
    } while (!inputValidated);
    return parsedInput;
  }

  public static String getStringInput() {
    Scanner keyboard = new Scanner(System.in);
    return keyboard.nextLine();
  }

  /**
   * Get Boolean Input
   * 
   * @return boolean
   */
  public static boolean getBooleanInput(String errorMessage) {
    Scanner keyboard = new Scanner(System.in);
    boolean parsedInput = false;
    boolean inputValidated = false;
    do {
      String input = keyboard.nextLine().trim().toLowerCase();
      if (input.equals("true") || input.equals("t") || input.equals("yes") || input.equals("y")) {
        inputValidated = true;
        parsedInput = true;
      } else if (input.equals("false") || input.equals("f") || input.equals("no") || input.equals("n"))
        inputValidated = true;
      else
        log("\nError, \"" + input + "\" is invalid! Enter only \"true\" or \"false\"\n" + errorMessage);
    } while (!inputValidated);
    return parsedInput;
  }
}