Example how an iterator can look like to use a BlockingQueue in java's foreach so this blocks if nothing in it.

Iterables.java

    public class Iterables {
		public static <Type> Iterable<Type> iterable(final BlockingQueue<Type> queue){
			return new Iterable<Type>() {
				@Override
				public Iterator<Type> iterator() {
					return new Iterator<Type>() {

						@Override
						public boolean hasNext() {
							return true;
						}

						@Override
						public Type next() {
							try {
								return queue.take();
							} catch (InterruptedException e) {
								throw new RuntimeException(e);
							}
						}

						@Override
						public void remove() {	
						}
					};
				}
			};
		}
	}