/** Delivers next (i.e., first undelivered) value from input key-value pairs */
public String next() throws NoSuchElementException {
if (!hasNext()) throw new NoSuchElementException("No more key-value pairs for this key");
String value = WmrReducerImpl.nextValue;
WmrReducerImpl.advance();
return value;
}
public boolean hasNext() {
return !WmrReducerImpl.endInput() && (WmrReducerImpl.nextKey.equals(myKey));
}