code: public ItemImpl getItemByIdentifier(String identifier, boolean pool) throws RepositoryException
     {
        return getItemByIdentifier(identifier, pool, true);
     }
docs: Return item by identifier in this transient storage then in workspace container.
  
  @param identifier
  - identifier of searched item
  @param pool
  - indicates does the item fall in pool
  @return existed item data or null if not found
  @throws RepositoryException