private AVLNode removeSelf()

in src/main/java/org/apache/commons/collections4/list/TreeList.java [535:584]
45 lines of code
13 McCabe index (conditional complexity)

        private AVLNode<E> removeSelf() {
            if (getRightSubTree() == null && getLeftSubTree() == null) {
                return null;
            }
            if (getRightSubTree() == null) {
                if (relativePosition > 0) {
                    left.relativePosition += relativePosition;
                }
                left.max().setRight(null, right);
                return left;
            }
            if (getLeftSubTree() == null) {
                right.relativePosition += relativePosition - (relativePosition < 0 ? 0 : 1);
                right.min().setLeft(null, left);
                return right;
            }

            if (heightRightMinusLeft() > 0) {
                // more on the right, so delete from the right
                final AVLNode<E> rightMin = right.min();
                value = rightMin.value;
                if (leftIsPrevious) {
                    left = rightMin.left;
                }
                right = right.removeMin();
                if (relativePosition < 0) {
                    relativePosition++;
                }
            } else {
                // more on the left or equal, so delete from the left
                final AVLNode<E> leftMax = left.max();
                value = leftMax.value;
                if (rightIsNext) {
                    right = leftMax.right;
                }
                final AVLNode<E> leftPrevious = left.left;
                left = left.removeMax();
                if (left == null) {
                    // special case where left that was deleted was a double link
                    // only occurs when height difference is equal
                    left = leftPrevious;
                    leftIsPrevious = true;
                }
                if (relativePosition > 0) {
                    relativePosition--;
                }
            }
            recalcHeight();
            return this;
        }