parameter_handler.hpp

// Copyright (c) 2025 Maurice Alexander Purnawan
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
 
#ifndef NAV2_UTIL__PARAMETER_HANDLER_HPP_
#define NAV2_UTIL__PARAMETER_HANDLER_HPP_
 
#include <string>
#include <vector>
#include <memory>
#include <algorithm>
#include <mutex>
 
#include "nav2_ros_common/lifecycle_node.hpp"
#include "nav2_ros_common/node_utils.hpp"
 
namespace nav2_util
{
 
template<typename ParamsT>
class ParameterHandler
{
public:
  ParameterHandler(
    const nav2::LifecycleNode::SharedPtr & node,
    const rclcpp::Logger & logger)
  : node_(node), logger_(logger) {}
 
  virtual ~ParameterHandler() = default;
 
  std::mutex & getMutex() {return mutex_;}
 
  ParamsT * getParams() {return &params_;}
 
  void activate()
  {
    auto node = node_.lock();
    post_set_params_handler_ = node->add_post_set_parameters_callback(
      std::bind(&ParameterHandler::updateParametersCallback, this, std::placeholders::_1));
    on_set_params_handler_ = node->add_on_set_parameters_callback(
      std::bind(&ParameterHandler::validateParameterUpdatesCallback, this, std::placeholders::_1));
  }
 
  void deactivate()
  {
    auto node = node_.lock();
    if (post_set_params_handler_ && node) {
      node->remove_post_set_parameters_callback(post_set_params_handler_.get());
    }
    if (on_set_params_handler_ && node) {
      node->remove_on_set_parameters_callback(on_set_params_handler_.get());
    }
    post_set_params_handler_.reset();
    on_set_params_handler_.reset();
  }
 
protected:
  nav2::LifecycleNode::WeakPtr node_;
  std::mutex mutex_;
  ParamsT params_;
  rclcpp::Logger logger_;
  rclcpp::node_interfaces::PostSetParametersCallbackHandle::SharedPtr post_set_params_handler_;
  rclcpp::node_interfaces::OnSetParametersCallbackHandle::SharedPtr on_set_params_handler_;
 
  virtual rcl_interfaces::msg::SetParametersResult validateParameterUpdatesCallback(
    const std::vector<rclcpp::Parameter> & parameters) = 0;
 
  virtual void updateParametersCallback(const std::vector<rclcpp::Parameter> & parameters) = 0;
};
 
}  // namespace nav2_util
 
#endif  // NAV2_UTIL__PARAMETER_HANDLER_HPP_