Method lockedGetOrLoad

output/java_guava/1.4.17/LocalCache.java:2294–2367

(K key, int hash, CacheLoader<? super K, V> loader)

    }

    V lockedGetOrLoad(K key, int hash, CacheLoader<? super K, V> loader) throws ExecutionException {
      ReferenceEntry<K, V> e;
      ValueReference<K, V> valueReference = null;
      LoadingValueReference<K, V> loadingValueReference = null;
      boolean createNewEntry = true;
      lock();
      try {
        // re-read ticker once inside the lock
        long now = map.ticker.read();
        preWriteCleanup(now);
        int newCount = this.count - 1;
        AtomicReferenceArray<ReferenceEntry<K, V>> table = this.table;
        int index = hash & (table.length() - 1);
        ReferenceEntry<K, V> first = table.get(index);
        for (e = first; e != null; e = e.getNext()) {
          K entryKey = e.getKey();
          if (e.getHash() == hash && entryKey != null
              && map.keyEquivalence.equivalent(key, entryKey)) {
            valueReference = e.getValueReference();
            if (valueReference.isLoading()) {
              createNewEntry = false;
            } else {
              V value = valueReference.get();
              if (value == null) {
                enqueueNotification(entryKey, hash, value, valueReference.getWeight(), RemovalCause.COLLECTED);
              } else if (map.isExpired(e, now)) {
                // This is a duplicate check, as preWriteCleanup already purged expired
                // entries, but let's accomodate an incorrect expiration queue.
                enqueueNotification(entryKey, hash, value, valueReference.getWeight(), RemovalCause.EXPIRED);
              } else {
                recordLockedRead(e, now);
                statsCounter.recordHits(1);
                // we were concurrent with loading; don't consider refresh
                return value;
              }

              // immediately reuse invalid entries
              writeQueue.remove(e);
              accessQueue.remove(e);
              this.count = newCount; // write-volatile
            }
            break;
          }
        }
        if (createNewEntry) {
          loadingValueReference = new LoadingValueReference<K, V>();
          if (e == null) {
            e = newEntry(key, hash, first);
            e.setValueReference(loadingValueReference);
            table.set(index, e);
          } else {
            e.setValueReference(loadingValueReference);
          }
        }
      } finally {
        unlock();
        postWriteCleanup();
      }