Simple utility class to automatically generate long ids

LongId.java

import java.util.concurrent.atomic.AtomicLong;
import java.util.function.Predicate;

public class LongId {

  private final AtomicLong atomicLong = new AtomicLong(0);

  public long generateId(Predicate<Long> exists) {
    if(this.atomicLong.get() == Integer.MAX_VALUE) {
      this.atomicLong.set(0);
    }
    long id = this.atomicLong.incrementAndGet();
    if(exists.test(id)) {
      id = generateId(exists);
    }
    return id;
  }

}