@Nullable
  @IsLocked (ELockType.READ)
  protected final INTERFACETYPE getAtIndex (@Nonnegative final int nIndex)
  {
    return m_aRWLock.readLocked ( () -> CollectionHelper.getAtIndex (m_aMap.values (), nIndex));
  }
@ Nullable @ IsLocked ( ELockType . READ ) protected final INTERFACETYPE getAtIndex ( @ Nonnegative final int nIndex ) { return m_aRWLock . readLocked ( ( ) -> CollectionHelper . getAtIndex ( m_aMap . values ( ) , nIndex ) ) ; }
Get the item at the specified index. This method only returns defined
results if an ordered map is used for data storage.

@param nIndex
The index to retrieve. Should be &ge; 0.
@return <code>null</code> if an invalid index was provided.