java - Idiomatic way to use for-each loop given an iterator? -

when enhanced loop (foreach loop) added java, made work target of either array or iterable.

for ( t item : /*t[] or iterable<? extends t>*/ ) {     //use item } 

that works great collection classes implement 1 type of iteration, , have single iterator() method.

but find myself incredibly frustrated odd time want use non-standard iterator collection class. example, trying use deque lifo/stack print elements in fifo order. forced this:

for (iterator<t> = mydeque.descendingiterator(); it.hasnext(); ) {    t item = it.next();    //use item } 

i lose advantages of for-each loop. it's not keystrokes. don't exposing iterator if don't have to, since it's easy make mistake of calling it.next() twice, etc.

now ideally think for-each loop should have accepted iterator well. doesn't. there idiomatic way of using for-each loop in these circumstances? i'd love hear suggestions use common collections libraries guava.

the best can come in absense of helper method/class is:

for ( t item : new iterable<t>() { public iterator<t> iterator() { return mydeque.descendingiterator(); } } ) {     //use item } 

which isn't worth using.

i'd love see guava have iterables.wrap make idiomatic, didn't find that. roll own iterator wrapper via class or helper method. other ideas?

edit: side-note, can give valid reason why enhanced for-loop shouldn't have been able accept iterator? go long way making me live current design.

what i'd make utility class called deques support this, along other utilities if desired.

public class deques {   private deques() {}    public static <t> iterable<t> asdescendingiterable(final deque<t> deque) {     return new iterable<t>() {       public iterator<t> iterator() {         return deque.descendingiterator();       }     }   } } 

this case it's bad don't have lambdas , method references yet. in java 8, you'll able write given method reference descendingiterator() matches signature of iterable:

deque<string> deque = ... (string s : deque::descendingiterator) { ... }