/**
   * @param key Key to add to read set.
   * @param val Value.
   * @param drVer Data center replication version.
   * @param skipStore Skip store flag.
   * @throws IgniteCheckedException If failed.
   * @return {@code True} if entry has been enlisted.
   */
  public boolean addEntry(
      GridCacheContext cacheCtx,
      IgniteTxKey key,
      GridCacheOperation op,
      CacheObject val,
      @Nullable GridCacheVersion drVer,
      boolean skipStore)
      throws IgniteCheckedException {
    checkInternal(key);

    GridNearCacheEntry cached = cacheCtx.near().peekExx(key.key());

    try {
      if (cached == null) {
        evicted.add(key);

        return false;
      } else {
        cached.unswap();

        CacheObject peek = cached.peek(true, false, false, null);

        if (peek == null && cached.evictInternal(false, xidVer, null)) {
          cached.context().cache().removeIfObsolete(key.key());

          evicted.add(key);

          return false;
        } else {
          IgniteTxEntry txEntry =
              new IgniteTxEntry(cacheCtx, this, op, val, -1L, -1L, cached, drVer, skipStore);

          writeMap.put(key, txEntry);

          return true;
        }
      }
    } catch (GridCacheEntryRemovedException ignore) {
      evicted.add(key);

      if (log.isDebugEnabled())
        log.debug(
            "Got removed entry when adding reads to remote transaction (will ignore): " + cached);

      return false;
    }
  }
  /**
   * @param entry Entry to enlist.
   * @throws IgniteCheckedException If failed.
   * @return {@code True} if entry was enlisted.
   */
  private boolean addEntry(IgniteTxEntry entry) throws IgniteCheckedException {
    checkInternal(entry.txKey());

    GridCacheContext cacheCtx = entry.context();

    if (!cacheCtx.isNear()) cacheCtx = cacheCtx.dht().near().context();

    GridNearCacheEntry cached = cacheCtx.near().peekExx(entry.key());

    if (cached == null) {
      evicted.add(entry.txKey());

      return false;
    } else {
      cached.unswap();

      try {
        CacheObject val = cached.peek(true, false, false, null);

        if (val == null && cached.evictInternal(false, xidVer, null)) {
          evicted.add(entry.txKey());

          return false;
        } else {
          // Initialize cache entry.
          entry.cached(cached);

          writeMap.put(entry.txKey(), entry);

          addExplicit(entry);

          return true;
        }
      } catch (GridCacheEntryRemovedException ignore) {
        evicted.add(entry.txKey());

        if (log.isDebugEnabled())
          log.debug("Got removed entry when adding to remote transaction (will ignore): " + cached);

        return false;
      }
    }
  }