diff --git a/demo_nodes_cpp/CMakeLists.txt b/demo_nodes_cpp/CMakeLists.txt index 867425d30..0a1832e63 100644 --- a/demo_nodes_cpp/CMakeLists.txt +++ b/demo_nodes_cpp/CMakeLists.txt @@ -48,6 +48,7 @@ custom_executable(parameters list_parameters_async) custom_executable(parameters parameter_events) custom_executable(parameters parameter_events_async) custom_executable(parameters parameter_node) +custom_executable(parameters even_parameters_node) custom_executable(parameters set_and_get_parameters) custom_executable(parameters set_and_get_parameters_async) diff --git a/demo_nodes_cpp/src/parameters/even_parameters_node.cpp b/demo_nodes_cpp/src/parameters/even_parameters_node.cpp new file mode 100644 index 000000000..fab5bc157 --- /dev/null +++ b/demo_nodes_cpp/src/parameters/even_parameters_node.cpp @@ -0,0 +1,86 @@ +// Copyright 2018 Open Source Robotics Foundation, Inc. +// +// 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. + +#include +#include + +#include "rclcpp/rclcpp.hpp" + +class EvenParameterNode : public rclcpp::Node +{ +public: + EvenParameterNode() + : Node("even_parameters_node") + { + // Declare a parameter change request callback + // This function will enforce that only setting even integer parameters is allowed + // any other change will be discarded + auto param_change_callback = + [this](std::vector parameters) -> rcl_interfaces::msg::SetParametersResult + { + auto result = rcl_interfaces::msg::SetParametersResult(); + result.successful = true; + for (auto parameter : parameters) { + rclcpp::ParameterType parameter_type = parameter.get_type(); + if (rclcpp::ParameterType::PARAMETER_NOT_SET == parameter_type) { + RCLCPP_INFO(this->get_logger(), + "parameter '%s' deleted successfully", + parameter.get_name().c_str() + ); + result.successful &= true; + } else if (rclcpp::ParameterType::PARAMETER_INTEGER == parameter_type) { + if (parameter.as_int() % 2 != 0) { + RCLCPP_INFO(this->get_logger(), + "Requested value '%d' for parameter '%s' is not an even number:" + " rejecting change...", + parameter.as_int(), + parameter.get_name().c_str() + ); + result.successful = false; + } else { + RCLCPP_INFO(this->get_logger(), + "parameter '%s' has changed and is now: %s", + parameter.get_name().c_str(), + parameter.value_to_string().c_str() + ); + result.successful &= true; + } + } else { + RCLCPP_INFO(this->get_logger(), + "only integer parameters can be set\n" + "requested value for parameter '%s' is not an even number, rejecting change...", + parameter.get_name().c_str() + ); + result.successful = false; + } + } + return result; + }; + this->register_param_change_callback(param_change_callback); + } +}; + +int main(int argc, char ** argv) +{ + // Force flush of the stdout buffer. + setvbuf(stdout, NULL, _IONBF, BUFSIZ); + + rclcpp::init(argc, argv); + + auto node = std::make_shared(); + + rclcpp::spin(node); + rclcpp::shutdown(); + return 0; +}