Personal blog of Stein Magnus Jodal Zola 2011-03-15T00:00:00+00:00 https://jodal.dev/tags/scala/atom.xml 2011-03-15T00:00:00+00:00 2011-03-15T00:00:00+00:00 Unknown https://jodal.dev/2011/03/15/traits-in-python-using-multiple-inheritance/

<p>As you probably know, if a class needs to handle two mostly unrelated concerns, the class should probably be split into two. This way, your will achieve <a rel="external" href="http://en.wikipedia.org/wiki/Cohesion_(computer_science)">higher cohesion</a> in your code, which is generally considered a good thing. Though, there are times where you need to address two mostly unrelated concerns in a single class.</p> <p>The Scala programming language has a concept they call <a rel="external" href="http://www.scala-lang.org/node/126">traits</a>. Scala traits can be compared to Java interfaces, except that Scala traits may be partially or fully implemented, like abstract classes. As with Java interfaces, you can <em>mixin</em> multiple traits in a class. If any of the traits has colliding method signatures, the last trait mixed in overrides the earlier ones. Just as with regular inheritance and interfaces, the class <em>must</em> implement any methods that has not been implemented by the traits, and <em>may</em> override any methods that already has been implemented.</p>