code: public ItemImpl getItemByIdentifier(String identifier, boolean pool, boolean apiRead) throws RepositoryException
     {
        long start = 0;
        if (LOG.isDebugEnabled())
        {
           start = System.currentTimeMillis();
           LOG.debug("getItemByIdentifier(" + identifier + " ) >>>>>");
        }
  
        ItemImpl item = null;
        try
        {
           return item = readItem(getItemData(identifier), null, pool, apiRead);
        }
        finally
        {
           if (LOG.isDebugEnabled())
           {
              LOG.debug("getItemByIdentifier(" + identifier + ") --> " + (item != null ? item.getPath() : "null")
                 + "  <<<<< " + ((System.currentTimeMillis() - start) / 1000d) + "sec");
           }
        }
     }
docs: For internal use, required privileges. 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
  @param apiRead
  - if true will call postRead Action and check permissions
  @return existed item data or null if not found
  @throws RepositoryException