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         public static boolean askBoolean(final String prompt) {
  25
  26                 final BufferedReader br = new BufferedReader(new InputStreamReader(
  27                                 System.in));
  28
  29                 while (true)
  30                         try {
  31                                 System.out.print(prompt);
  32
  33                                 final String userInput = br.readLine().toLowerCase();
  34
  35                                 if ("y".equals(userInput) || "yes".equals(userInput)
  36                                                 || "true".equals(userInput))
  37                                         return true;
  38
  39                                 if ("n".equals(userInput) || "no".equals(userInput)
  40                                                 || "false".equals(userInput))
  41                                         return false;
  42
  43                                 System.out
  44                                                 .println("Invalid input. You shall enter y/yes/true or n/no/false.");
  45                         } catch (final IOException ioe) {
  46                                 ioe.printStackTrace();
  47                         }
  48         }
  49
  50         /**
  51          * Ask numerical long value from user on command-line.
  52          */
  53         public static long askLong(final String prompt) {
  54
  55                 final BufferedReader br = new BufferedReader(new InputStreamReader(
  56                                 System.in));
  57
  58                 while (true) {
  59                         System.out.print(prompt);
  60
  61                         try {
  62                                 final String userInput = br.readLine();
  63
  64                                 try {
  65                                         final long result = Long.parseLong(userInput);
  66                                         return result;
  67                                 } catch (final NumberFormatException e) {
  68                                         System.out.println("\nError: You shall enter an integer.");
  69                                 }
  70                         } catch (final IOException ioe) {
  71                                 ioe.printStackTrace();
  72                         }
  73
  74                 }
  75         }
  76
  77         /**
  78          * Ask string value from user on command-line.
  79          */
  80         public static String askString(final String prompt) {
  81
  82                 final BufferedReader br = new BufferedReader(new InputStreamReader(
  83                                 System.in));
  84
  85                 while (true) {
  86                         System.out.print(prompt);
  87
  88                         try {
  89                                 final String userInput = br.readLine();
  90
  91                                 return userInput;
  92                         } catch (final IOException ioe) {
  93                                 ioe.printStackTrace();
  94                         }
  95
  96                 }
  97         }
  98
  99 }