本例使用boost::signals2库实现中介者模式。
其中Game是各个player持有的中介者。Coach负责连接Game和各个player的事件。
程序结构如下，
test/CMakeLists.txt
cmake_minimum_required(VERSION 2.6)
if(APPLE)
message(STATUS "This is Apple, do nothing.")
set(CMAKE_MACOSX_RPATH 1)
set(CMAKE_PREFIX_PATH /Users/aabjfzhu/software/vcpkg/ports/cppwork/vcpkg_installed/x64-osx/share )
elseif(UNIX)
message(STATUS "This is linux, set CMAKE_PREFIX_PATH.")
set(CMAKE_PREFIX_PATH /vcpkg/ports/cppwork/vcpkg_installed/x64-linux/share)
endif(APPLE)
project(event_broker)
set(CMAKE_CXX_STANDARD 20)
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wno-narrowing")
add_definitions(-g)
find_package(ZLIB)
find_package(OpenCV REQUIRED )
find_package(Arrow CONFIG REQUIRED)
find_package(unofficial-brotli REQUIRED)
find_package(unofficial-utf8proc CONFIG REQUIRED)
find_package(Thrift CONFIG REQUIRED)
find_package(glog REQUIRED)
find_package(OpenSSL REQUIRED)
find_package(Boost REQUIRED COMPONENTS
system
filesystem
serialization
program_options
thread
)
find_package(DataFrame REQUIRED)
if(APPLE)
MESSAGE(STATUS "This is APPLE, set INCLUDE_DIRS")
set(INCLUDE_DIRS ${Boost_INCLUDE_DIRS} /usr/local/include /usr/local/iODBC/include /opt/snowflake/snowflakeodbc/include/ ${CMAKE_CURRENT_SOURCE_DIR}/../include/ ${CMAKE_CURRENT_SOURCE_DIR}/../../../include)
elseif(UNIX)
MESSAGE(STATUS "This is linux, set INCLUDE_DIRS")
set(INCLUDE_DIRS ${Boost_INCLUDE_DIRS} /usr/local/include ${CMAKE_CURRENT_SOURCE_DIR}/../include/ ${CMAKE_CURRENT_SOURCE_DIR}/../../../include/)
endif(APPLE)
if(APPLE)
MESSAGE(STATUS "This is APPLE, set LINK_DIRS")
set(LINK_DIRS /usr/local/lib /usr/local/iODBC/lib /opt/snowflake/snowflakeodbc/lib/universal)
elseif(UNIX)
MESSAGE(STATUS "This is linux, set LINK_DIRS")
set(LINK_DIRS ${Boost_INCLUDE_DIRS} /usr/local/lib /vcpkg/ports/cppwork/vcpkg_installed/x64-linux/lib)
endif(APPLE)
if(APPLE)
MESSAGE(STATUS "This is APPLE, set ODBC_LIBS")
set(ODBC_LIBS iodbc iodbcinst)
elseif(UNIX)
MESSAGE(STATUS "This is linux, set LINK_DIRS")
set(ODBC_LIBS odbc odbcinst ltdl)
endif(APPLE)
include_directories(${INCLUDE_DIRS})
LINK_DIRECTORIES(${LINK_DIRS})
file( GLOB test_file_list ${CMAKE_CURRENT_SOURCE_DIR}/*.cpp)
file( GLOB APP_SOURCES ${CMAKE_CURRENT_SOURCE_DIR}/../impl/*.cpp ${CMAKE_CURRENT_SOURCE_DIR}/../include/*.h ${CMAKE_CURRENT_SOURCE_DIR}/../include/*.cpp ${CMAKE_CURRENT_SOURCE_DIR}/../../../include/arr_/impl/*.cpp ${CMAKE_CURRENT_SOURCE_DIR}/../../../include/http/impl/*.cpp ${CMAKE_CURRENT_SOURCE_DIR}/../../../include/yaml/impl/*.cpp ${CMAKE_CURRENT_SOURCE_DIR}/../../../include/df/impl/*.cpp ${CMAKE_CURRENT_SOURCE_DIR}/../../../include/death_handler/impl/*.cpp)
add_library(${PROJECT_NAME}_lib SHARED ${APP_SOURCES} ${test_file})
target_link_libraries(${PROJECT_NAME}_lib ${Boost_LIBRARIES} ZLIB::ZLIB glog::glog DataFrame::DataFrame ${OpenCV_LIBS})
target_link_libraries(${PROJECT_NAME}_lib OpenSSL::SSL OpenSSL::Crypto libgtest.a pystring libyaml-cpp.a libgmock.a ${ODBC_LIBS} libnanodbc.a pthread dl backtrace libzstd.a libbz2.a libsnappy.a re2::re2 parquet lz4 unofficial::brotli::brotlidec-static unofficial::brotli::brotlienc-static unofficial::brotli::brotlicommon-static utf8proc thrift::thrift arrow arrow_dataset)
foreach( test_file ${test_file_list} )
file(RELATIVE_PATH filename ${CMAKE_CURRENT_SOURCE_DIR} ${test_file})
string(REPLACE ".cpp" "" file ${filename})
add_executable(${file} ${test_file})
target_link_libraries(${file} ${PROJECT_NAME}_lib)
endforeach( test_file ${test_file_list})
test/event_broker_test.cpp
#include "soccer.hpp"
#include <glog/logging.h>
#include <gtest/gtest.h>
#include <fstream>
#include <memory>
#include <algorithm>
#include "death_handler/death_handler.h"
int main(int argc, char** argv) {
FLAGS_log_dir = "./";
FLAGS_alsologtostderr = true;
// 日志级别 INFO, WARNING, ERROR, FATAL 的值分别为0、1、2、3
FLAGS_minloglevel = 0;
Debug::DeathHandler dh;
google::InitGoogleLogging("./logs.log");
testing::InitGoogleTest(&argc, argv);
int ret = RUN_ALL_TESTS();
return ret;
}
// 使用boost::signals2 库实现 教练向所有队员说话
// 其中game是中介者，被所有player持有，负责向所有player发消息
GTEST_TEST(EventBrokerTests, EventBroker) {
Game game;
Player player {"sam", game};
Coach coach {game};
player.score();
player.score();
player.score();
player.score();
}
include/soccer.hpp
#ifndef _FREDRIC_SOCCER_HPP_
#define _FREDRIC_SOCCER_HPP_
#include <boost/signals2.hpp>
#include <iostream>
namespace sig = boost::signals2;
struct EventData {
virtual ~EventData() = default;
virtual void print() const = 0;
};
struct PlayerScoredData: EventData {
std::string player_name;
int goals_scored_so_far;
PlayerScoredData(std::string const& player_name_, int const goals_scored_so_far_): player_name{player_name_}, goals_scored_so_far{goals_scored_so_far_} {
}
void print() const override {
std::cout << player_name << " has scored! (their " <<
goals_scored_so_far << " goal)" << "\n";
}
};
// 观察者
struct Game {
sig::signal<void(EventData*)> events;
};
struct Player {
std::string name;
int goals_scored{0};
Game& game;
Player(std::string const& name_, Game& game_): name{name_}, game{game_} {
}
void score() {
++ goals_scored;
PlayerScoredData ps {name, goals_scored};
// Send events once scored
game.events(&ps);
}
};
struct Coach {
Game& game;
explicit Coach(Game& game_): game{game_} {
// Celebrate if player has scored < 3 goals
game.events.connect([](EventData* e){
PlayerScoredData* ps = dynamic_cast<PlayerScoredData*>(e);
ps->print();
if(ps && ps->goals_scored_so_far < 3) {
std::cout << "coach says: well done, " << ps->player_name << "\n";
}
});
}
};
#endif
程序输出如下，
