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    <p>I guess most of the above answers are valid, but I'm not sure any are correct.</p> <p>The correct answer is, you very rarely switch in an OO language, it indicates you are doing your OO wrong. In this case, it's a perfect indication that your Enum class has problems.</p> <p>You should just be calling Console.WriteLine(mood.moodMessage()), and defining moodMessage for each of the states.</p> <p>If a new state is added--All Your Code Should Adapt Automatically, nothing should fail, throw an exception or need changes.</p> <p>Edit: response to comment.</p> <p>In your example, to be "Good OO" the functionality of the file mode would be controlled by the FileMode object. It could contain a delegate object with "open, read, write..." operations that are different for each FileMode, so File.open("name", FileMode.Create) could be implemented as (sorry about the lack of familiarity with the API):</p> <pre><code>open(String name, FileMode mode) { // May throw an exception if, for instance, mode is Open and file doesn't exist // May also create the file depending on Mode FileHandle fh = mode.getHandle(name); ... code to actually open fh here... // Let Truncate and append do their special handling mode.setPosition(fh); } </code></pre> <p>This is much neater than trying to do it with switches... (by the way, the methods would be both package-private and possibly delegated to "Mode" classes)</p> <p>When OO is done well, every single method looks like a few lines of really understandable, simple code--TOO simple. You always get the feeling that there is some big messy "Cheese Nucleus" holding together all the little nacho objects, but you can't ever find it--it's nachos all the way down...</p>
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    1. POWhat is the preferred method for handling unexpected enum values?
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    1. COJust like everything else, enums are good when they are used correctly. For example, if I am designing an API for file handling, I'd make `File.Open(string filename, FileMode mode)` where FileMode is a simple value enum, with no behavior attached to it. I don't see this "doing OO wrong".
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    2. COWoah, I didn't say anything about enums being bad! I LOVE typesafe enumerations!--and the use you specified there is great. It's the switch statement that's problematic. That indicates that a behavior should be moved into the enum.
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    3. COSorry if I misunderstood, but the question still remains: how do you implement `File.Open` without a switch statement? Talking about myself, I wouldn't give FileMode objects a method to open a file, because it simply doesn't belong there. What do you suggest as an alternative?
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