src/main/java/eu/svjatoslav/commons/commandline/CLIHelper.java

   1 /*
   2  * Svjatoslav Commons - shared library of common functionality.
   3  * Copyright ©2012-2014, Svjatoslav Agejenko, svjatoslav@svjatoslav.eu
   4  *
   5  * This program is free software; you can redistribute it and/or
   6  * modify it under the terms of version 3 of the GNU Lesser General Public License
   7  * or later as published by the Free Software Foundation.
   8  */
   9
  10 package eu.svjatoslav.commons.commandline;
  11
  12 import java.io.BufferedReader;
  13 import java.io.IOException;
  14 import java.io.InputStreamReader;
  15
  16 /**
  17  * Command-line interface helper.
  18  */
  19 public class CLIHelper {
  20
  21         /**
  22          * Ask boolean value from user on command-line.
  23          *
  24          * @param prompt
  25          *            to show to the user
  26          * @return <code>true</code> is user answered affirmative.
  27          */
  28         public static boolean askBoolean(final String prompt) {
  29
  30                 final BufferedReader br = new BufferedReader(new InputStreamReader(
  31                                 System.in));
  32
  33                 while (true)
  34                         try {
  35                                 System.out.print(prompt);
  36
  37                                 final String userInput = br.readLine().toLowerCase();
  38
  39                                 if ("y".equals(userInput) || "yes".equals(userInput)
  40                                                 || "true".equals(userInput))
  41                                         return true;
  42
  43                                 if ("n".equals(userInput) || "no".equals(userInput)
  44                                                 || "false".equals(userInput))
  45                                         return false;
  46
  47                                 System.out
  48                                                 .println("Invalid input. You shall enter y/yes/true or n/no/false.");
  49                         } catch (final IOException ioe) {
  50                                 ioe.printStackTrace();
  51                         }
  52         }
  53
  54         /**
  55          * Ask numerical long value from user on command-line.
  56          *
  57          * @param prompt
  58          *            to show to the user
  59          * @return value given by user
  60          */
  61         public static long askLong(final String prompt) {
  62
  63                 final BufferedReader br = new BufferedReader(new InputStreamReader(
  64                                 System.in));
  65
  66                 while (true) {
  67                         System.out.print(prompt);
  68
  69                         try {
  70                                 final String userInput = br.readLine();
  71
  72                                 try {
  73                                         final long result = Long.parseLong(userInput);
  74                                         return result;
  75                                 } catch (final NumberFormatException e) {
  76                                         System.out.println("\nError: You shall enter an integer.");
  77                                 }
  78                         } catch (final IOException ioe) {
  79                                 ioe.printStackTrace();
  80                         }
  81
  82                 }
  83         }
  84
  85         /**
  86          * Ask string value from user on command-line.
  87          *
  88          * @param prompt
  89          *            to show to the user
  90          * @return value given by the user
  91          */
  92         public static String askString(final String prompt) {
  93
  94                 final BufferedReader br = new BufferedReader(new InputStreamReader(
  95                                 System.in));
  96
  97                 while (true) {
  98                         System.out.print(prompt);
  99
 100                         try {
 101                                 final String userInput = br.readLine();
 102
 103                                 return userInput;
 104                         } catch (final IOException ioe) {
 105                                 ioe.printStackTrace();
 106                         }
 107
 108                 }
 109         }
 110
 111 }