🚀 go-pugleaf

Russell,

probably the easiest solution is to put all passwords into a 
static set and check each new password. 
Declare the generatePassword method synchonized to handle 
multiple threads:

private static HashSet passwords = new HashSet();

public static synchonized String generatePassword() {
  StringBuffer strbuff = new StringBuffer();
  String result = null;
  do {
    for(int i = 0 ; i < 6 ; i++) {     
      strbuff.append(alphabets.charAt((int)(Math.random()*  
      (alphabets.length()- 1))));
    }
    result = strbuff.toString();
  } while (!passwords.add(result)); //will fail for duplicates
  return result;
}

Note that this is a transient solution, your password set will 
be lost when your app finishes. You could for instance 
serialize the set to get a persistent solution. Or you use a 
database table for that.

Torsten 

Russell <weetat@cesmainternational.com> wrote:
>
>  Hi all ,
>  I am using RedHat6.1 and jdk1.3.
>
>  I have code below :
>
>  public void generatePassword(){
>
>   StringBuffer strbuff = new StringBuffer();
>
>   for(int i = 0 ; i < 6 ; i++){
>     
>strbuff.append(alphabets.charAt((int)(Math.random()*(alphabets.length()
>- 1))));
>    }
>  }
>
>  As you all know ,the code below random generate password . However how
>i am going to check if the generate password is
>  unique if the code is run by two threads ??
>
>  Anybody have any ideas ?? Thanks wt.