private void ensureUpToDate()

in geronimo-metrics-common/src/main/java/org/apache/geronimo/microprofile/metrics/common/HistogramImpl.java [156:185]

• 29 lines of code
• 4 McCabe index (conditional complexity)

    private void ensureUpToDate() {
        final long next = nextRefreshTime.get();
        final long now = System.nanoTime();
        if (now < next) {
            return;
        }

        final Lock lock = this.lock.writeLock();
        lock.lock();
        try {
            if (nextRefreshTime.compareAndSet(next, now + REFRESH_INTERVAL)) {
                final long oldStartTime = startTime;
                startTime = nowSec();
                final double updateFactor = Math.exp(-ALPHA * (startTime - oldStartTime));
                if (updateFactor != 0.) {
                    bucket.putAll(new ArrayList<>(bucket.keySet()).stream()
                            .collect(toMap(k -> k * updateFactor, k -> {
                                final Value previous = bucket.remove(k);
                                return new Value(previous.value, previous.weight * updateFactor);
                            })));
                    count.set(bucket.size()); // N keys can lead to the same key so we must update it
                } else {
                    bucket.clear();
                    count.set(0);
                }
            }
        } finally {
            lock.unlock();
        }
    }