本例使用STL标准模板库中的std::vector来组织责任链。
其他代码逻辑与手写责任链一致。
程序目录结构如下，
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(list_chain)
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/list_chain_test.cpp
#include "death_handler/death_handler.h"
#include <glog/logging.h>
#include "list_chain.hpp"
#include <gtest/gtest.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;
}
GTEST_TEST(ListChainTests, ListChainAllChain) {
Creature goblin {"Goblin", 1, 1};
CreatureModifierChain chain;
DoubleAttackModifier r1 {goblin};
DoubleAttackModifier r1_2 {goblin};
IncreaseDefenseModifer r2 {goblin};
chain.add(&r1);
chain.add(&r1_2);
chain.add(&r2);
chain.handle();
std::cout << goblin << "\n";
}
GTEST_TEST(ListChainTests, ListChainBreakChain) {
Creature goblin {"Goblin", 1, 1};
CreatureModifierChain chain;
NoBonusesModifier nm {goblin};
DoubleAttackModifier r1 {goblin};
DoubleAttackModifier r1_2 {goblin};
IncreaseDefenseModifer r2 {goblin};
chain.add(&nm);
chain.add(&r1);
chain.add(&r1_2);
chain.add(&r2);
chain.handle();
std::cout << goblin << "\n";
}
include/list_chain.hpp
#ifndef _FREDRIC_LIST_CHAIN_HPP_
#define _FREDRIC_LIST_CHAIN_HPP_
#include <string>
#include <iostream>
#include <sstream>
#include <vector>
#include <utility>
#include <type_traits>
#include <typeinfo>
struct Creature {
std::string name;
int attack, defense;
Creature(std::string const& name_, int attack_, int defense_): name{name_}, attack{attack_}, defense{defense_} {
}
friend std::ostream& operator<<(std::ostream& os, Creature const& c) {
os << "name: " << c.name << " attack: " << c.attack << " defense: " << c.defense;
return os;
}
};
class CreatureModifer {
protected:
Creature& creature;
public:
CreatureModifer(Creature& creature_): creature{creature_} {}
virtual void handle() = 0;
};
class DoubleAttackModifier: public CreatureModifer {
public:
DoubleAttackModifier(Creature& creature_): CreatureModifer(creature_) {}
void handle() override {
creature.attack *= 2;
}
};
class IncreaseDefenseModifer: public CreatureModifer {
public:
IncreaseDefenseModifer(Creature& creature_): CreatureModifer(creature_) {}
void handle() override {
if(creature.attack <= 2)
++ creature.defense;
}
};
class NoBonusesModifier: public CreatureModifer {
public:
NoBonusesModifier(Creature& creature_): CreatureModifer(creature_) {}
// 啥都不干，断开链接
void handle() override {
}
};
struct CreatureModifierChain{
std::vector<CreatureModifer*> modifiers{};
void add(CreatureModifer* modifier) {
modifiers.emplace_back(modifier);
}
void handle() {
for(auto&& modifier: modifiers) {
if(typeid(*modifier) == typeid(NoBonusesModifier)) {
break;
} else {
modifier->handle();
}
}
}
};
#endif
程序输出如下，
