@Override public boolean contains(OIdentifiable identifiable) { if (newEntries.containsKey(identifiable)) return true; Change counter = changes.get(identifiable); if (counter != null) { AbsoluteChange absoluteValue = getAbsoluteValue(identifiable); if (counter.isUndefined()) { changes.put(identifiable, absoluteValue); } counter = absoluteValue; } else { counter = getAbsoluteValue(identifiable); } return counter.applyTo(0) > 0; }