code: public boolean isVisible(long version) {
      // either it was committed before or the change belongs to current tx
      return (version <= getReadPointer() && !isExcluded(version)) ||
          (isCurrentWrite(version) &&
              (visibilityLevel != VisibilityLevel.SNAPSHOT_EXCLUDE_CURRENT || writePointer != version));
    }
docs: Returns whether or not the given version should be visible to the current transaction.  A version will be visible
  if it was successfully committed prior to the current transaction starting, or was written by the current
  transaction (using either the current write pointer or the write pointer from a prior checkpoint).
  
  @param version the data version to check for visibility
  @return true if the version is visible, false if it should be hidden (filtered)
  
  @see #setVisibility(VisibilityLevel) to control whether the current write pointer is visible.