/guava/guava/src/com/google/common/util/concurrent/AtomicLongMap.java
noValue.set ( true ) ; return newValue;
AtomicBoolean noValue = new AtomicBoolean(false); Long result = map.compute( key, (k, oldValue) -> { if (oldValue == null || oldValue == 0) { <extra_id_0> } else { return oldValue; } }); return noValue.get() ? 0L : requireNonNull(result).longValue(); }