code: public void changeSequencerField( MappedAttributeDefinition defn,
                                        ModelNode newValue,
                                        String sequencerName ) throws RepositoryException, OperationFailedException {
          ModeShapeEngine engine = getEngine();
          String repositoryName = repositoryName();
  
          // Get a snapshot of the current configuration ...
          RepositoryConfiguration config = engine.getRepositoryConfiguration(repositoryName);
  
          // Now start to make changes ...
          Editor editor = config.edit();
  
          // Find the array of sequencer documents ...
          List<String> pathToContainer = defn.getPathToContainerOfField();
          EditableDocument sequencing = editor.getOrCreateDocument(pathToContainer.get(0));
          EditableDocument sequencers = sequencing.getOrCreateArray(pathToContainer.get(1));
  
          // The container should be an array ...
          for (String configuredSequencerName : sequencers.keySet()) {
              // Look for the entry with a name that matches our sequencer name ...
              if (sequencerName.equals(configuredSequencerName)) {
                  // All these entries should be nested documents ...
                  EditableDocument sequencer = (EditableDocument)sequencers.get(configuredSequencerName);
  
                  // Change the field ...
                  String fieldName = defn.getFieldName();
                  // Get the raw value from the model node ...
                  Object rawValue = defn.getTypedValue(newValue);
                  // And update the field ...
                  sequencer.set(fieldName, rawValue);
                  break;
              }
          }
  
          // Get and apply the changes to the current configuration. Note that the 'update' call asynchronously
          // updates the configuration, and returns a Future<JcrRepository> that we could use if we wanted to
          // wait for the changes to take place. But we don't want/need to wait, so we'll not use the Future ...
          Changes changes = editor.getChanges();
          engine.update(repositoryName, changes);
      }
docs: Immediately change and apply the specified sequencer field in the current repository configuration to the new value.
  
  @param defn the attribute definition for the value; may not be null
  @param newValue the new string value
  @param sequencerName the name of the sequencer
  @throws RepositoryException if there is a problem obtaining the repository configuration or applying the change
  @throws OperationFailedException if there is a problem obtaining the raw value from the supplied model node