poll() — netty Function Reference

Architecture documentation for the poll() function in MpscIntQueue.java from the netty codebase.

Function java CommonUtil Concurrent called by 1

Entity Profile

CommonUtil→ Concurrent→ poll() — netty Function Reference

Dependency Diagram

graph TD
  6c53d641_1124_ccce_e265_4ede0841b9c5["poll()"]
  c00a7e8d_e19a_6d4a_6887_5d0634281bed["MpscAtomicIntegerArrayQueue"]
  6c53d641_1124_ccce_e265_4ede0841b9c5 -->|defined in| c00a7e8d_e19a_6d4a_6887_5d0634281bed
  fb7f0fff_a870_3ec4_c353_7341bc7fdd2e["offer()"]
  fb7f0fff_a870_3ec4_c353_7341bc7fdd2e -->|calls| 6c53d641_1124_ccce_e265_4ede0841b9c5
  style 6c53d641_1124_ccce_e265_4ede0841b9c5 fill:#6366f1,stroke:#818cf8,color:#fff

Relationship Graph

Source Code

common/src/main/java/io/netty/util/concurrent/MpscIntQueue.java lines 160–183

        @Override
        public int poll() {
            final long cIndex = consumerIndex;
            final int offset = (int) (cIndex & mask);
            // If we can't see the next available element we can't poll
            int value = get(offset);
            if (emptyValue == value) {
                /*
                 * NOTE: Queue may not actually be empty in the case of a producer (P1) being interrupted after
                 * winning the CAS on offer but before storing the element in the queue. Other producers may go on
                 * to fill up the queue after this element.
                 */
                if (cIndex != producerIndex) {
                    do {
                        value = get(offset);
                    } while (emptyValue == value);
                } else {
                    return emptyValue;
                }
            }
            lazySet(offset, emptyValue);
            CONSUMER_INDEX.lazySet(this, cIndex + 1);
            return value;
        }