public V put()

in src/main/java/org/apache/commons/collections4/trie/AbstractPatriciaTrie.java [2016:2071]
43 lines of code
11 McCabe index (conditional complexity)

    public V put(final K key, final V value) {
        Objects.requireNonNull(key, "key");

        final int lengthInBits = lengthInBits(key);

        // The only place to store a key with a length
        // of zero bits is the root node
        if (lengthInBits == 0) {
            if (root.isEmpty()) {
                incrementSize();
            } else {
                incrementModCount();
            }
            return root.setKeyValue(key, value);
        }

        final TrieEntry<K, V> found = getNearestEntryForKey(key, lengthInBits);
        if (compareKeys(key, found.key)) {
            if (found.isEmpty()) { // <- must be the root
                incrementSize();
            } else {
                incrementModCount();
            }
            return found.setKeyValue(key, value);
        }

        final int bitIndex = bitIndex(key, found.key);
        if (!KeyAnalyzer.isOutOfBoundsIndex(bitIndex)) {
            if (KeyAnalyzer.isValidBitIndex(bitIndex)) { // in 99.999...9% the case
                /* NEW KEY+VALUE TUPLE */
                final TrieEntry<K, V> t = new TrieEntry<>(key, value, bitIndex);
                addEntry(t, lengthInBits);
                incrementSize();
                return null;
            }
            if (KeyAnalyzer.isNullBitKey(bitIndex)) {
                // A bits of the Key are zero. The only place to
                // store such a Key is the root Node!

                /* NULL BIT KEY */
                if (root.isEmpty()) {
                    incrementSize();
                } else {
                    incrementModCount();
                }
                return root.setKeyValue(key, value);

            }
            if (KeyAnalyzer.isEqualBitKey(bitIndex) && found != root) { // NOPMD
                incrementModCount();
                return found.setKeyValue(key, value);
            }
        }

        throw new IllegalArgumentException("Failed to put: " + key + " -> " + value + ", " + bitIndex);
    }