OptVisitor.java

/**
 * Visitor interface for processing {@code Opt} instances.
 *
 * @param <T> the type of the contained value
 * @param <R> the return type of the visitor
 */
public interface OptVisitor<T, R> {
 /**
 * Processes a {@code Some} instance.
 *
 * @param some the {@code Some} instance
 * @return the result of processing
 */
 R visit(Opt.Some<T> some);

 /**
 * Processes a {@code None} instance.
 *
 * @param none the {@code None} instance
 * @return the result of processing
 */
 R visit(Opt.None<T> none);
}