* returns <tt>Integer.MIN_VALUE</tt> if no such key exists.
*/
public int keyOf(final int value) {
final int[] foundKey = new int[1];
boolean notFound = forEachPair(
new IntIntProcedure() {
public boolean apply(int iterKey, int iterValue) {
boolean found = value == iterValue;
if (found) foundKey[0] = iterKey;
return !found;
}