private void swapPosition()

in src/main/java/org/apache/commons/collections4/bidimap/TreeBidiMap.java [2080:2169]
72 lines of code
17 McCabe index (conditional complexity)

    private void swapPosition(final Node<K, V> x, final Node<K, V> y, final DataElement dataElement) {
        // Save initial values.
        final Node<K, V> xFormerParent = x.getParent(dataElement);
        final Node<K, V> xFormerLeftChild = x.getLeft(dataElement);
        final Node<K, V> xFormerRightChild = x.getRight(dataElement);
        final Node<K, V> yFormerParent = y.getParent(dataElement);
        final Node<K, V> yFormerLeftChild = y.getLeft(dataElement);
        final Node<K, V> yFormerRightChild = y.getRight(dataElement);
        final boolean xWasLeftChild =
                x.getParent(dataElement) != null && x == x.getParent(dataElement).getLeft(dataElement);
        final boolean yWasLeftChild =
                y.getParent(dataElement) != null && y == y.getParent(dataElement).getLeft(dataElement);

        // Swap, handling special cases of one being the other's parent.
        if (x == yFormerParent) { // x was y's parent
            x.setParent(y, dataElement);

            if (yWasLeftChild) {
                y.setLeft(x, dataElement);
                y.setRight(xFormerRightChild, dataElement);
            } else {
                y.setRight(x, dataElement);
                y.setLeft(xFormerLeftChild, dataElement);
            }
        } else {
            x.setParent(yFormerParent, dataElement);

            if (yFormerParent != null) {
                if (yWasLeftChild) {
                    yFormerParent.setLeft(x, dataElement);
                } else {
                    yFormerParent.setRight(x, dataElement);
                }
            }

            y.setLeft(xFormerLeftChild, dataElement);
            y.setRight(xFormerRightChild, dataElement);
        }

        if (y == xFormerParent) { // y was x's parent
            y.setParent(x, dataElement);

            if (xWasLeftChild) {
                x.setLeft(y, dataElement);
                x.setRight(yFormerRightChild, dataElement);
            } else {
                x.setRight(y, dataElement);
                x.setLeft(yFormerLeftChild, dataElement);
            }
        } else {
            y.setParent(xFormerParent, dataElement);

            if (xFormerParent != null) {
                if (xWasLeftChild) {
                    xFormerParent.setLeft(y, dataElement);
                } else {
                    xFormerParent.setRight(y, dataElement);
                }
            }

            x.setLeft(yFormerLeftChild, dataElement);
            x.setRight(yFormerRightChild, dataElement);
        }

        // Fix children's parent pointers
        if (x.getLeft(dataElement) != null) {
            x.getLeft(dataElement).setParent(x, dataElement);
        }

        if (x.getRight(dataElement) != null) {
            x.getRight(dataElement).setParent(x, dataElement);
        }

        if (y.getLeft(dataElement) != null) {
            y.getLeft(dataElement).setParent(y, dataElement);
        }

        if (y.getRight(dataElement) != null) {
            y.getRight(dataElement).setParent(y, dataElement);
        }

        x.swapColors(y, dataElement);

        // Check if root changed
        if (rootNode[dataElement.ordinal()] == x) {
            rootNode[dataElement.ordinal()] = y;
        } else if (rootNode[dataElement.ordinal()] == y) {
            rootNode[dataElement.ordinal()] = x;
        }
    }