code: public CmsAlias readAliasByPath(CmsRequestContext context, String siteRoot, String path) throws CmsException {
  
          CmsDbContext dbc = m_dbContextFactory.getDbContext(context);
          try {
              CmsAlias alias = m_driverManager.readAliasByPath(dbc, context.getCurrentProject(), siteRoot, path);
              return alias;
          } catch (Exception e) {
              dbc.report(null, Messages.get().container(Messages.ERR_DB_OPERATION_0), e);
              return null; // will never be executed
          } finally {
              dbc.clear();
          }
      }
docs: Reads the alias with a given path in a given site.<p>
  
  @param context the current request context
  @param siteRoot the site root
  @param path the site relative alias path
  @return the alias for the path, or null if no such alias exists
  
  @throws CmsException if something goes wrong