private void restructure()

in ttl-core/src/main/java/com/alibaba/ttl3/internal/util/ConcurrentReferenceHashMap.java [611:668]
49 lines of code
14 McCabe index (conditional complexity)

        private void restructure(boolean allowResize, @Nullable Reference<K, V> ref) {
            boolean needsResize;
            lock();
            try {
                int countAfterRestructure = this.count.get();
                Set<Reference<K, V>> toPurge = Collections.emptySet();
                if (ref != null) {
                    toPurge = new HashSet<>();
                    while (ref != null) {
                        toPurge.add(ref);
                        ref = this.referenceManager.pollForPurge();
                    }
                }
                countAfterRestructure -= toPurge.size();

                // Recalculate taking into account count inside lock and items that
                // will be purged
                needsResize = (countAfterRestructure > 0 && countAfterRestructure >= this.resizeThreshold);
                boolean resizing = false;
                int restructureSize = this.references.length;
                if (allowResize && needsResize && restructureSize < MAXIMUM_SEGMENT_SIZE) {
                    restructureSize <<= 1;
                    resizing = true;
                }

                // Either create a new table or reuse the existing one
                Reference<K, V>[] restructured =
                        (resizing ? createReferenceArray(restructureSize) : this.references);

                // Restructure
                for (int i = 0; i < this.references.length; i++) {
                    ref = this.references[i];
                    if (!resizing) {
                        restructured[i] = null;
                    }
                    while (ref != null) {
                        if (!toPurge.contains(ref)) {
                            Entry<K, V> entry = ref.get();
                            if (entry != null) {
                                int index = getIndex(ref.getHash(), restructured);
                                restructured[index] = this.referenceManager.createReference(
                                        entry, ref.getHash(), restructured[index]);
                            }
                        }
                        ref = ref.getNext();
                    }
                }

                // Replace volatile members
                if (resizing) {
                    this.references = restructured;
                    this.resizeThreshold = (int) (this.references.length * getLoadFactor());
                }
                this.count.set(Math.max(countAfterRestructure, 0));
            } finally {
                unlock();
            }
        }