code: public CmsAliasImportResult importRewriteAlias(
          CmsRequestContext requestContext,
          String siteRoot,
          String source,
          String target,
          CmsAliasMode mode)
      throws CmsException {
  
          CmsDbContext dbc = m_dbContextFactory.getDbContext(requestContext);
          try {
              return m_driverManager.importRewriteAlias(dbc, siteRoot, source, target, mode);
          } catch (Exception e) {
              dbc.report(null, Messages.get().container(Messages.ERR_DB_OPERATION_0), e);
              return null;
          } finally {
              dbc.clear();
          }
      }
docs: Imports a rewrite alias.<p>
  
  @param requestContext the current request context
  @param siteRoot the site root
  @param source the rewrite alias source
  @param target the rewrite alias target
  @param mode the alias mode
  @return the import result
  
  @throws CmsException if something goes wrong