Method GetNext

pkg/database/iterators.go:62–87

GetNext returns the next unique Tuple from the two TupleIterators.

()

// GetNext returns the next unique Tuple from the two TupleIterators.
func (i *UniqueTupleIterator) GetNext() (*base.Tuple, bool) {
	// Check the first iterator for any next Tuples
	for i.iterator1.HasNext() {
		tup := i.iterator1.GetNext() // Get the next Tuple
		key := tuple.ToString(tup)
		// If the Tuple hasn't been visited yet, mark it as visited and return it
		if _, found := i.visited[key]; !found {
			i.visited[key] = true
			return tup, true
		}
	}

	// If no more unique Tuples are in the first iterator, check the second one
	for i.iterator2.HasNext() {
		tup := i.iterator2.GetNext() // Get the next Tuple
		key := tuple.ToString(tup)
		// If the Tuple hasn't been visited yet, mark it as visited and return it
		if _, found := i.visited[key]; !found {
			i.visited[key] = true
			return tup, true
		}
	}

	// If no more unique Tuples are in either of the iterators, return nil
	return &base.Tuple{}, false
}

// UniqueAttributeIterator combines two AttributeIterators and ensures that only unique Attributes are returned.
// Uniqueness is based on the Attribute's pointer address.