use*_*186 5 c++ go template-method-pattern
在Go中实现模板方法模式是否有一种优雅的规范方法?在C++中,它看起来像这样:
#include <iostream>
#include <memory>
class Runner {
public:
void Start() {
// some prepare stuff...
Run();
}
private:
virtual void Run() = 0;
};
class Logger : public Runner {
private:
virtual void Run() override {
std::cout << "Running..." << std::endl;
}
};
int main() {
std::unique_ptr<Runner> l = std::make_unique<Logger>();
l->Start();
return 0;
}
在golang我写了这样的东西:
package main
import (
"fmt"
"time"
)
type Runner struct {
doRun func()
needStop bool
}
func (r *Runner) Start() {
go r.doRun()
}
func NewRunner(f func()) *Runner {
return &Runner{f, false}
}
type Logger struct {
*Runner
i int
}
func NewLogger() *Logger {
l := &Logger{}
l.doRun = l.doRunImpl
return l
}
func (l *Logger) doRunImpl() {
time.Sleep(1 * time.Second)
fmt.Println("Running")
}
func main() {
l := NewLogger()
l.Start()
fmt.Println("Hello, playground")
}
但是此代码因运行时空指针错误而失败.基本思想是将一些功能从派生类(结构化)混合到基类例程,其方式是从这个混合派生例程中获得基类状态.