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javaenumerationiterable

Why aren't Enumerations Iterable?

In Java 5 and above you have the foreach loop, which works magically on anything that implements Iterable:

for (Object o : list) {
  doStuff(o);
}

However, Enumerable still does not implement Iterable, meaning that to iterate over an Enumeration you must do the following:

for(; e.hasMoreElements() ;) {
  doStuff(e.nextElement());
}

Does anyone know if there is a reason why Enumeration still does not implement Iterable?

Edit: As a clarification, I'm not talking about the language concept of an enum, I'm talking a Java-specific class in the Java API called 'Enumeration'.

Solution

  • Enumeration hasn't been modified to support Iterable because it's an interface not a concrete class (like Vector, which was modifed to support the Collections interface).

    If Enumeration was changed to support Iterable it would break a bunch of people's code.