code: public Object execute(final Map<Object, Object> iArgs) {
      if (attribute == null)
        throw new OCommandExecutionException("Cannot execute the command because it has not been parsed yet");
  
      final OCluster cluster = getCluster();
  
      if (cluster == null)
        throw new OCommandExecutionException("Cluster '" + clusterName + "' not found");
  
      if (clusterId > -1 && clusterName.equals(String.valueOf(clusterId))) {
        clusterName = cluster.getName();
      } else {
        clusterId = cluster.getId();
      }
  
      try {
        cluster.set(attribute, value);
      } catch (IOException ioe) {
        throw new OCommandExecutionException("Error altering cluster '" + clusterName + "'", ioe);
      }
  
      return null;
    }
docs: Execute the ALTER CLASS.