public IntersectionResult apply()

in src/main/java/org/apache/commons/text/similarity/IntersectionSimilarity.java [168:204]
25 lines of code
8 McCabe index (conditional complexity)

    public IntersectionResult apply(final CharSequence left, final CharSequence right) {
        if (left == null || right == null) {
            throw new IllegalArgumentException("Input cannot be null");
        }

        // Create the elements from the sequences
        final Collection<T> objectsA = converter.apply(left);
        final Collection<T> objectsB = converter.apply(right);
        final int sizeA = objectsA.size();
        final int sizeB = objectsB.size();

        // Short-cut if either collection is empty
        if (Math.min(sizeA, sizeB) == 0) {
            // No intersection
            return new IntersectionResult(sizeA, sizeB, 0);
        }

        // Intersection = count the number of shared elements
        final int intersection;
        if (objectsA instanceof Set && objectsB instanceof Set) {
            // If a Set then the elements will only have a count of 1.
            // Iterate over the smaller set.
            intersection = sizeA < sizeB
                    ? getIntersection((Set<T>) objectsA, (Set<T>) objectsB)
                    : getIntersection((Set<T>) objectsB, (Set<T>) objectsA);
        } else  {
            // Create a bag for each collection
            final TinyBag bagA = toBag(objectsA);
            final TinyBag bagB = toBag(objectsB);
            // Iterate over the smaller number of unique elements
            intersection = bagA.uniqueElementSize() < bagB.uniqueElementSize()
                    ? getIntersection(bagA, bagB)
                    : getIntersection(bagB, bagA);
        }

        return new IntersectionResult(sizeA, sizeB, intersection);
    }