How to Use AtomicInteger for Generating Limited Sequences in Java

How can I implement AtomicInteger to generate a limited sequence in Java?

AtomicInteger sequence = new AtomicInteger(0);

int getNextSequence() {
    return sequence.getAndUpdate(n -> (n + 1) % maxLimit);
}

AtomicInteger is a part of the java.util.concurrent package, providing an integer value that may be updated atomically. It's ideal for generating sequence numbers in multithreaded environments without the need for synchronized methods or blocks. By leveraging its atomic operations, you can easily create limited sequences by wrapping the increment logic and applying a modulus operator to enforce limits.

import java.util.concurrent.atomic.AtomicInteger;

public class LimitedSequenceGenerator {
    private final AtomicInteger sequence = new AtomicInteger(0);
    private final int maxLimit;

    public LimitedSequenceGenerator(int maxLimit) {
        this.maxLimit = maxLimit;
    }

    public int getNextSequence() {
        return sequence.getAndUpdate(n -> (n + 1) % maxLimit);
    }
}

Causes

• Concurrency issues when generating sequences across multiple threads.
• Potential sequence overflows if not implemented carefully.

Solutions

• Wrap the increment operation within an AtomicInteger to avoid race conditions.
• Use a modulus operation to ensure the sequence stays within defined limits.

Mistake: Not handling the maximum limit properly which can cause negative sequences.

Solution: Always ensure to apply the modulus operator to maintain the value within bounds.

Mistake: Neglecting to initialize AtomicInteger correctly in a multithreaded environment.

Solution: Always initialize AtomicInteger with a starting value before using it.