Partial updates in an immutable World

This post was prompted by a conversation with a good friend, who is an experienced Java developer taking their first, tentative, steps towards becoming a Scala programmer. Basically, the conversation went as follows:

“…Immutability seems good and like a goal I should aim for. How can I get this in my domain objects without having to provide a multiplicity of constructors to do partial updates ? Is it really that big a deal ? I’ve rarely had to worry about this stuff in Java at all !”

Both fair question, which I’ll try to address in the remainder of this post. Continue reading