I want to create unique user id

Question

I just create unique id but with random number. but I want to create that id like jason-001,smith-002,etc.

Integer user_id= new Random().nextInt();

//implementation
reference_uploaded_by.getRef().setValue(name.getText().toString() + "-" + user_id);

If this ID is for _identification_, why not use a UUID? like `id = UUID.randomUUID().toString();` — Martin Marconcini, Sep 15 '19 at 16:28
Are you asking how to best to create a unique user id? Or are you asking specifically how to create a string consisting of name plus a sequence number? Work to make your Question narrowly-focused and very specific. — Basil Bourque, Sep 15 '19 at 18:12

Miha_x64 · Accepted Answer · 2019-09-16T08:55:14.660

You can use AtomicLong#incrementAndGet as a counter. The “Atomic” means the class is thread-safe.

AtomicLong userIdIncrementor = new AtomicLong(previouslyUsedNumber);

Use that object to get incrementing numbers for each new user.

long number = userIdIncrementor.incrementAndGet();
String userId = userName + String.format("%03d", number);

This code assumes you will never have more than a thousand users, with only three digits for the number as you specified in your Question.

For details on formatting an integer, see this Answer.

1 Answers1