Enums With Default Throw Clause?

Posted by Tom Tresansky on Stack Overflow See other posts from Stack Overflow or by Tom Tresansky
Published on 2010-05-20T19:07:53Z Indexed on 2010/05/20 19:10 UTC
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java

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enums

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java5

I noticed the following in the Java Language spec in the section on enumerations here: link

switch(this) {
  case PLUS:   return x + y;
  case MINUS:  return x - y;
  case TIMES:  return x * y;
  case DIVIDE: return x / y;
}
throw new AssertionError("Unknown op: " + this);

However, looking at the switch statement definition section, I didn't notice this particular syntax (the associated throw statement) anywhere.

Can I use this sort of "default case is throw an exception" syntactic sugar outside of enum definitions? Does it have any special name? Is this considered a good/bad practice for short-cutting this behavior of "anything not in the list throws an exception"?

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