protected void checkTableModifiable(final MasterProcedureEnv env) throws IOException {
    // Checks whether the table exists
    if (!env.getMasterServices().getTableDescriptors().exists(getTableName())) {
      throw new TableNotFoundException(getTableName());
    }
  }
Check whether a table is modifiable - exists and either offline or online with config set
@param env MasterProcedureEnv
hbase-server/src/main/java/org/apache/hadoop/hbase/master/procedure/AbstractStateMachineTableProcedure.java