A class for obtaining random numbers

Package com. Wen;

Import java. util .*;
Import java. Security. securerandom;
Import java. Security. nosuchalgorithmexception;
Import java. Security. nosuchproviderexception;

/**
* A class to obtain random numbers
* About use: We can get a random number in the 0-9 A-Z A-Z.
* Randomstr. setcharset ("0-9"); // range
* Randomstr. setlength ("8"); // Length
* Randomstr. generaterandomobject ();
* Random number (random type) = randomstr. getrandom ();
* <P> copyright: 2004 </P>
* @ Author assumerwg
* @ Version 1.1
*/

Public class randomstr {
Static string randomstr;
Static Boolean allchars = false;
// The missing string is an 8-Bit String.
Static integer length = new INTEGER (8 );
Static hashmap hmap;
Static arraylist lower = NULL;
Static arraylist upper = NULL;
Static char [] single = NULL;
Static int singlecount = 0;
Static Boolean singles = false;
Static string algorithm = NULL;
Static string provider = NULL;
Static Boolean secure = false;
Static random = NULL;
Static securerandom secrandom = NULL;

Private Static float getfloat (){
If (random = NULL ){
Return secrandom. nextfloat ();
}
Else {
Return random. nextfloat ();
}
}

Public static void generaterandomobject () throws exception {
// Check to see if the object is a securerandom object
If (secure ){
Try {
// Get an instance of a securerandom object
If (provider! = NULL ){

Random = securerandom. getinstance (algorithm, provider );
}
Else {
Random = securerandom. getinstance (algorithm );
}
}
Catch (nosuchalgorithmexception ne ){
Throw new exception (ne. getmessage ());
}
Catch (nosuchproviderexception PE ){
Throw new exception (PE. getmessage ());
}
}
Else {
Random = new random ();
}
}

/**
* Generate the random string
*/
Private Static void generaterandom (){
If (allchars ){
For (INT I = 0; I <length. intvalue (); I ++ ){
Randomstr = randomstr +
New character (char) (INT) 34 + (INT) (getfloat () * 93 )))).
Tostring ();
}
}
Else if (Singles ){
// Check if there are single chars to be encoded DED
If (upper. Size () = 3 ){
// Check for the number of ranges Max 3 uppercase lowercase digits build the random string
For (INT I = 0; I <length. intvalue (); I ++ ){
// You have four groups to choose a random number from, to make
// The choice a little more random select a number out of 100 get a random number even or odd
If (INT) (getfloat () * 100) % 2 = 0 ){
// The number was even get another number even or odd
If (INT) (getfloat () * 100) % 2 = 0 ){
// Choose a random char from the single char Group
Randomstr = randomstr + randomsingle (). tostring ();
}
Else {
// Get a random char from the first range
Randomstr = randomstr +
Randomchar (character) lower. Get (2), (character) Upper. Get (2 )).
Tostring ();
}
}
Else {
// The number was odd

If (INT) (getfloat () * 100) % 2 = 0 ){
// Choose a random char from the second range
Randomstr = randomstr +
Randomchar (character) lower. Get (1), (character) Upper. Get (1 )).
Tostring ();
}
Else {
// Choose a random char from the third range
Randomstr = randomstr +
Randomchar (character) lower. Get (0), (character) Upper. Get (0 )).
Tostring ();
}
}
}
}
Else if (upper. Size () = 2 ){
// Single chars are to be encoded ded choose a random char from
// Two different ranges build the random char from single chars and two ranges
For (INT I = 0; I <length. intvalue (); I ++ ){
// Select the single chars or a range to get each random charfrom

If (INT) (getfloat () * 100) % 2 = 0 ){
// Get random char from the single chars
Randomstr = randomstr + randomsingle (). tostring ();
}
Else if (INT) (getfloat () * 100) % 2 = 0 ){
// Get the random char from the first range
Randomstr = randomstr +
Randomchar (character) lower. Get (1), (character) Upper. Get (1 )).
Tostring ();
}
Else {
// Get the random char from the second range
Randomstr = randomstr +
Randomchar (character) lower. Get (0), (character) Upper. Get (0 )).
Tostring ();
}
}
}
Else if (upper. Size () = 1 ){
// Build the random string from single chars and one range
For (INT I = 0; I <length. intvalue (); I ++ ){
If (INT) getfloat () * 100) % 2 = 0 ){
// Get a random single char
Randomstr = randomstr + randomsingle (). tostring ();
}
Else {
// Get a random char from the range
Randomstr = randomstr +
Randomchar (character) lower. Get (0), (character) Upper. Get (0 )).
Tostring ();
}
}
}
Else {
// Build the Rand string from single chars
For (INT I = 0; I <length. intvalue (); I ++ ){
Randomstr = randomstr + randomsingle (). tostring ();
}
}
}
Else {
// No single chars are to be encoded in the random string
If (upper. Size () = 3 ){
// Build random strng from three ranges
For (INT I = 0; I <length. intvalue (); I ++ ){
If (INT) (getfloat () * 100) % 2 = 0 ){
// Get random char from first range
Randomstr = randomstr +
Randomchar (character) lower. Get (2), (character) Upper. Get (2 )).
Tostring ();
}
Else if (INT) (getfloat () * 100) % 2 = 0 ){
// Get random char form second range
Randomstr = randomstr +
Randomchar (character) lower. Get (1), (character) Upper. Get (1 )).
Tostring ();
}
Else {
// Get random char from third range
Randomstr = randomstr +
Randomchar (character) lower. Get (0), (character) Upper. Get (0 )).
Tostring ();
}
}
}
Else if (upper. Size () = 2 ){
// Build random string from two ranges
For (INT I = 0; I <length. intvalue (); I ++ ){
If (INT) (getfloat () * 100) % 2 = 0 ){
// Get random char from first range
Randomstr = randomstr +
Randomchar (character) lower. Get (1), (character) Upper. Get (1 )).
Tostring ();
}
Else {
// Get random char from second range
Randomstr = randomstr +
Randomchar (character) lower. Get (0), (character) Upper. Get (0 )).
Tostring ();
}
}
}
Else {
// Build random string
For (INT I = 0; I <length. intvalue (); I ++ ){
// Get random char from only range
Randomstr = randomstr +
Randomchar (character) lower. Get (0), (character) Upper. Get (0 )).
Tostring ();
}
}
}
}

/**
* Generate a random char from the single char list
*
* @ Returns-A randomly selscted character from the single char list
*
*/
Private Static character randomsingle (){
Return (new character (single [(INT) (getfloat () * singlecount)-1)]);
}

/**
* Generate a random character
*
* @ Param lower bound from which to get a random char
* @ Param upper bound from which to get a random char
*
* @ Returns-A randomly generated character
*
*/
Private Static character randomchar (character lower, character upper ){
Int tempval;
Char low = lower. charvalue ();
Char up = upper. charvalue ();

// Get a random number in the range lowlow-lowup
Tempval = (INT) Low + (getfloat () * (INT) (up-low ))));

// Return the random char
Return (new character (char) tempval ));
}

/**
* Get the randomly created string for use with
* & Lt; JSP: getproperty name = <I> "ID" </I> property = "randomstr"/& gt;
*
* @ Return-randomly created string
*
*/
Public static string getrandom (){
Randomstr = new string ();
Generaterandom (); // generate the first random string

If (hmap! = NULL ){

While (hmap. containskey (randomstr )){
// Random string has already been created generate a different one
Generaterandom ();
}

Hmap. Put (randomstr, null); // Add the new random string
}

Return randomstr;
}

/**
* Set the ranges from which to choose the characters for the random string
* @ Param low set of lower ranges
* @ Param up set of upper ranges
*
*/
Public static void setranges (arraylist low, arraylist up ){
Lower = low;
Upper = up;
}

/**
* Set the hashmap that is used to check the uniqueness of random strings
* @ Param map hashmap whose keys are used to insure uniqueness of random strgs
*/
Public static void sethmap (hashmap map ){
Hmap = map;
}

/**
* Set the length of the random string
* @ Param value length of the random string
*/
Public static void setlength (string value ){
Length = new INTEGER (value );
}
Public static void setlength (INT value ){
Length = new INTEGER (value );
}
/**
* Set the algorithm name
* @ Param Value Name of the algorithm to use for a securerandom object
*/
Public static void setalgorithm (string value ){
Algorithm = value;
Secure = true; // A securerandom object is to be used
}

/**
* Set the provider name
* @ Param Value Name of the package to check for the algorithm
*/
Public static void setprovider (string value ){
Provider = value;
}

/**
* Set the allchars flag
* @ Param value Boolean value of the allchars flag
*/
Public static void setallchars (Boolean value ){
Allchars = value;
}

/**
* Set the array of single chars to choose from for this random string and
* Number of chars in the array
* @ Param chars the array of single chars
* @ Param value the number of single chars
*
*/
Public static void setsingle (char [] chars, int value ){
Single = chars; // set the array of chars
Singlecount = value; // set the number of chars in array single
Singles = true; // set flag that single chars are in use
}

Public static void setcharset (string value ){
// Values tells the method whether or not to check for single chars
Boolean more = true;

// Create the arraylists to hold the upper and lower bounds for the char
// Ranges
Lower = new arraylist (3 );
Upper = new arraylist (3 );

// User has chosen to use all possible characters in the random string
If (value. compareto ("all") = 0 ){
Allchars = true; // set allchars flag
// All chars are to be used so there are no single chars to sort
// Through
More = false;
}
Else if (value. charat (1) = '-') & (value. charat (0 )! = '//')){
// Run through the ranges at most 3
While (more & (value. charat (1) = '-')){
// Check to make sure that the dash is not the single char
If (value. charat (0) = '//'){
Break;
}
Else {
// Add upper and lower ranges to there list
Lower. Add (new character (value. charat (0 )));
Upper. Add (new character (value. charat (2 )));
}

// Check to see if there is more to the charset
If (value. Length () <= 3 ){
More = false;
}
Else {
// Create a new string so that the next range if there is one
// Starts it
Value = value. substring (3 );
}
}
}

// If more = false there are no single chars in the charset
If (more ){
Single = new char [30]; // create single

// Create a set of tokens from the string of single chars
Stringtokenizer tokens = new stringtokenizer (value );

While (tokens. hasmoretokens ()){
// Get the next token from the string
String token = tokens. nexttoken ();

If (token. Length ()> 1 ){
// Char is a-add it to the list
Single [singlecount ++] = '-';
}

// Add the current char to the list
Single [singlecount ++] = token. charat (0 );
}
}
If (lower = NULL) & (single = NULL )){
Setcharset ("a-zA-Z0-9 ");
}
}
/*
Public static void main (string [] ARGs ){
Try {
// Randomstr. setallchars (true );
Randomstr. setcharset ("0-9 ");
Randomstr. setlength (12 );
Randomstr. generaterandomobject ();
System. Out. println (randomstr. getrandom ());
} Catch (exception ex ){
Ex. printstacktrace ();
}
}
*/
}