Question

Number generation

Asked by: dlcnet

Hi Experts!

 I would like to generate a particular 10 digit number. The first 4 digits are related to userID and the rest 6 should be "random" or ordered but they must be synchronized since they are used as an unique identifiers. The ideea is to split the code in two. One who generates the 6 digits and later on I can add the 4 digits. How one can do that?

Thanks!

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Asked On
2008-03-07 at 03:53:01ID23222592
Tags

Java, J2EE, Struts

Topics

Java Programming Language

,

New to Java Programming

,

Jakarta Struts

Participating Experts
6
Points
500
Comments
9

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Answers

 

by: CEHJPosted on 2008-03-07 at 03:57:47ID: 21069145

You need to keep a record of numbers generated. You could use a Set, serialized if necessary

 

by: ksivananthPosted on 2008-03-07 at 03:59:55ID: 21069154

int first = ( int )( Math.random() * 1000000 ) ;
int second = ( int )( Math.random() * 10000 ) ;

String final = first + "" + second ;

 

by: CEHJPosted on 2008-03-07 at 04:11:12ID: 21069212

You need something like the following:

		Random r = new Random();
		int n = r.nextInt(899999) + 100000;
		String id = "ABCD";
		String uid = String.format("%s%d", id, n);
		System.out.printf("Generated id is %s\n", uid);

                                              
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by: krakatoaPosted on 2008-03-07 at 04:13:18ID: 21069219

Long time;
String partNumID;
time = new Long(System.currentTimeMillis());

partNumID = new Integer(Math.abs(time.hashCode())).toString().substring(0,6);

 

by: krakatoaPosted on 2008-03-07 at 04:59:49ID: 21069496

or rather :

Long time;
String partNumID;
StringBuffer reverse;

time = new Long(System.currentTimeMillis());
try{
Thread.sleep(100);
}catch(InterruptedException intex){}

reverse = new StringBuffer(new Integer(Math.abs(time.hashCode())).toString()).reverse();
partNumID = reverse.substring(0,6);

 

by: PascalHeraudPosted on 2008-03-07 at 06:50:00ID: 21070560

What is your problem ?
Generating the two different numbers 6 digit / 4 digit?
Generate the final number (10 digit ) giving the two first ?

What is the Java version you're using ?

 

by: neuromousePosted on 2008-03-14 at 03:15:29ID: 21124104

First: what kind of format should the number be in - can it be in String, or is it necessary for it to be an integer?


Regards,

neuromouse

 

by: dextPosted on 2008-03-14 at 20:57:43ID: 21131385

userID is unique, so, following code is enough....
you can test it.

    public static synchronized String getNumber(String id) {
        int rndNumber = ((int) (Math.random() * 1000000) ^ (int) System.currentTimeMillis()) % 1000000 + 1000000; // fill 0....
        String rndString = rndNumber + "";
        return id + rndString.substring(1);
    }

                                              
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by: krakatoaPosted on 2008-03-24 at 10:45:11ID: 21195209

I never did explain my code ...

It takes the hashcode of a string of the current system time in milliseconds, and reverses it (the extra milliseconds being evident at the right-hand end of the system time), using the first 6 of those positions as the unique result. If you put that code in a loop, you could generate about a quarter million values an hour. You can then iterate those values, prepending your UID complexion.

20120131-EE-VQP-002

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