Question

For example:

getBooks(author, title)

• If allowing author to be null, would return all books with specific title
• If allowing title to be null, would return all books for the specific author
• If allowing both to be null, would return all books regardless of title or author

To eliminate this, have the following functions:

getBooks(author) 
getBooks(title)  
getBooks(author, title)  
getBooks()

In the new functions, there might be redundant codes or if we group those redundant codes into a function, we will still get into a function having null parameters. What’s a better way to handle this – no redundant code and no null parameters?

Answer 1

Don’t overload so much:

getBooksByAuthor(author) 
getBooksByTitle(title)  
getBooksByAuthorAndTitle(author, title)  
getBooks()

Note that this will not reduce code reuse: These methods could reuse/share whatever code they needed to in their implementations