phw.util
Class Ask

java.lang.Object
  |
  +--phw.util.Ask

public class Ask

extends java.lang.Object

This Ask class contains a set of static methods for safe interactive input of individual primitive types. They will not return until an acceptable answer has been entered. The implementation techniques draw on those in the `Java Gently' textbook by Judy Bishop.

Author:

P.H.Welch

Method Summary

static boolean	Boolean(java.lang.String prompt) Ask.Boolean issues the prompt and returns a boolean depending on the first non-white-space character typed.
static byte	Byte(java.lang.String prompt, byte min, byte max) Ask.Byte issues the prompt and returns a byte between min and max inclusive.
static char	Char(java.lang.String prompt, char[] valid) Ask.Char issues the prompt and returns a char depending on the first non-white-space character typed.
static double	Double(java.lang.String prompt, double min, double max) Ask.Double issues the prompt and returns a double between min and max inclusive.
static float	Float(java.lang.String prompt, float min, float max) Ask.Float issues the prompt and returns a float between min and max inclusive.
static boolean	getOneTokenReply() Ask.getOneTokenReply returns whether multiple response tokens will be rejected.
static int	Int(java.lang.String prompt, int min, int max) Ask.Int issues the prompt and returns an int between min and max inclusive.
static long	Long(java.lang.String prompt, long min, long max) Ask.Long issues the prompt and returns an long between min and max inclusive.
static void	setOneTokenReply(boolean b) Ask.setOneTokenReply (true) specifies that more than one token in the user reply will be rejected, even if the first token is valid.
static short	Short(java.lang.String prompt, short min, short max) Ask.Short issues the prompt and returns a short between min and max inclusive.
static java.lang.String	string(java.lang.String prompt) Ask.string issues the prompt and returns the String that is typed.
static void	Void(java.lang.String prompt) Ask.Void issues the prompt and returns when is pressed.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

Int

public static int Int(java.lang.String prompt,
                      int min,
                      int max)

Ask.Int issues the prompt and returns an int between min and max inclusive. Keyboard errors in typing the reply are all trapped. The method will not return until a valid int has been entered in the indicated range.

Parameters:

prompt - the string used to prompt for input.

min - user input must have a value >= min.

max - user input must have a value <= max.

Returns:

user input complying with the rules.

Long

public static long Long(java.lang.String prompt,
                        long min,
                        long max)

Ask.Long issues the prompt and returns an long between min and max inclusive. Keyboard errors in typing the reply are all trapped. The method will not return until a valid long has been entered in the indicated range.

Parameters:

prompt - the string used to prompt for input.

min - user input must have a value >= min.

max - user input must have a value <= max.

Returns:

user input complying with the rules.

Byte

public static byte Byte(java.lang.String prompt,
                        byte min,
                        byte max)

Ask.Byte issues the prompt and returns a byte between min and max inclusive. Keyboard errors in typing the reply are all trapped. The method will not return until a valid byte has been entered in the indicated range.

Parameters:

prompt - the string used to prompt for input.

min - user input must have a value >= min.

max - user input must have a value <= max.

Returns:

user input complying with the rules.

Short

public static short Short(java.lang.String prompt,
                          short min,
                          short max)

Ask.Short issues the prompt and returns a short between min and max inclusive. Keyboard errors in typing the reply are all trapped. The method will not return until a valid short has been entered in the indicated range.

Parameters:

prompt - the string used to prompt for input.

min - user input must have a value >= min.

max - user input must have a value <= max.

Returns:

user input complying with the rules.

Float

public static float Float(java.lang.String prompt,
                          float min,
                          float max)

Ask.Float issues the prompt and returns a float between min and max inclusive. Keyboard errors in typing the reply are all trapped. The method will not return until a valid float has been entered in the indicated range.

Parameters:

prompt - the string used to prompt for input.

min - user input must have a value >= min.

max - user input must have a value <= max.

Returns:

user input complying with the rules.

Double

public static double Double(java.lang.String prompt,
                            double min,
                            double max)

Ask.Double issues the prompt and returns a double between min and max inclusive. Keyboard errors in typing the reply are all trapped. The method will not return until a valid double has been entered in the indicated range.

Parameters:

prompt - the string used to prompt for input.

min - user input must have a value >= min.

max - user input must have a value <= max.

Returns:

user input complying with the rules.

Boolean

public static boolean Boolean(java.lang.String prompt)

Ask.Boolean issues the prompt and returns a boolean depending on the first non-white-space character typed. 'y' or 'Y' cause true to be returned, while 'n' or 'N' cause false to be returned. Anything else is rejected.

Parameters:

prompt - the string used to prompt for input.

Returns:

whether the user typed yes or no (according to the above rules).

Char

public static char Char(java.lang.String prompt,
                        char[] valid)

Ask.Char issues the prompt and returns a char depending on the first non-white-space character typed. This character must be one in the valid character array. Anything else is rejected.

Parameters:

prompt - the string used to prompt for input.

valid - the array of characters defining valid user responses.

Returns:

user input complying with the rules.

Void

public static void Void(java.lang.String prompt)

Ask.Void issues the prompt and returns when is pressed.

Parameters:

prompt - the string used to prompt for a .

string

public static java.lang.String string(java.lang.String prompt)

Ask.string issues the prompt and returns the String that is typed.

Parameters:

prompt - the string used to prompt for input.

Returns:

whatever the user inputs.

setOneTokenReply

public static void setOneTokenReply(boolean b)

Ask.setOneTokenReply (true) specifies that more than one token in the user reply will be rejected, even if the first token is valid. This is the default condition for this class.

Ask.setOneTokenReply (false) specifies that multiple tokens are allowed, but that only the first will be processed.

The false allows user input to be documented with comments (in the second and following tokens) explaining the meaning of the first token, which contains the actual data. This is useful when preparing user input as a file, from which the standard input stream will later be redirected, so that each line of input can be documented.

Parameters:

b - if true, the response must consist of a single token - otherwise, multiple tokens are allowed but only the first will be processed.

getOneTokenReply

public static boolean getOneTokenReply()

Ask.getOneTokenReply returns whether multiple response tokens will be rejected.

Returns:

whether multiple response tokens will be rejected.