code: private void ajaxSetFlowLock(final Project project,
        final HashMap<String, Object> ret, final HttpServletRequest req)
        throws ServletException {
      final String flowName = getParam(req, FLOW_NAME_PARAM);
      final Flow flow = project.getFlow(flowName);
      if (flow == null) {
        ret.put(ERROR_PARAM,
            "Flow " + flowName + " not found in project " + project.getName());
        return;
      }
  
      boolean isLocked = Boolean.parseBoolean(getParam(req, FLOW_IS_LOCKED_PARAM));
  
      // if there is a change in the locked value, then check to see if the project has a flow trigger
      // that needs to be paused/resumed.
      if (isLocked != flow.isLocked()) {
        try {
          if (projectManager.hasFlowTrigger(project, flow)) {
            if (isLocked) {
              if (this.scheduler.pauseFlowTriggerIfPresent(project.getId(), flow.getId())) {
                logger.info("Flow trigger for flow " + project.getName() + "." + flow.getId() +
                        " is paused");
              } else {
                logger.warn("Flow trigger for flow " + project.getName() + "." + flow.getId() +
                " doesn't exist");
              }
            } else {
              if (this.scheduler.resumeFlowTriggerIfPresent(project.getId(), flow.getId())) {
                logger.info("Flow trigger for flow " + project.getName() + "." + flow.getId() +
                    " is resumed");
              } else {
                logger.warn("Flow trigger for flow " + project.getName() + "." + flow.getId() +
                    " doesn't exist");
              }
            }
          }
        } catch (Exception e) {
          ret.put(ERROR_PARAM, e);
        }
      }
  
      flow.setLocked(isLocked);
      ret.put(FLOW_IS_LOCKED_PARAM, flow.isLocked());
      ret.put(FLOW_ID_PARAM, flow.getId());
      this.projectManager.updateFlow(project, flow);
    }
docs: Set if a flow is locked.
  
  @param project the project for the flow.
  @param ret the return value.
  @param req the http request.
  @throws ServletException