手撸golang spring ioc/aop 之2
缘起
最近阅读 [Offer来了：Java面试核心知识点精讲（框架篇）] (王磊 , 2020.6)
本系列笔记拟采用golang练习之
Talk is cheap, show me the code.
Spring
Spring基于J2EE技术实现了一套轻量级的
Java Web Service系统应用框架。
它有很多优秀的特性，很多公司都选择把
Spring作为产品或项目的基础开发架构。
Spring的特性包括轻量、控制反转
（Inversion of Control, IoC）、
面向容器、面向切面（AspectOriented
Programming, AOP）和框架灵活等。
源码gitee地址：
https://gitee.com/ioly/learning.gooop
原文链接：
https://my.oschina.net/ioly
目标
- 参考spring常用注解，使用golang编写“基于注解的静态代码增强器/生成器”
配置： ComponentScan，Configuration, Bean
Bean声明：Component, Service, Controller
Bean注入：Autowried
AOP注解：Before, After, Around, PointCut
子目标（Day 2）
- 构思app的运行模式：
- 本地standlone模式运行
- 提供基于cli的命令行实时交互
- 生成旁路代码：只扫描源代码，不修改源代码，增强后的代码加统一后缀
- 设计cli交互指令集：
- config save：保存配置
- config saveas <name>：另存配置
- watch add <dir>：添加代码扫描目录
- watch del <dir>：移除代码扫描目录
- watch list：显示当前扫描的代码目录集合
- gen：生成增强代码，也就是扫描所有注解，并生成增强类和增强方法
设计
- config/IConfiguration：配置接口
- command/ICmd：指令接口
- command/ICmdBuilder：指令构建器接口
- command/ICmdContext：指令执行上下文接口
- config_cmd/SaveCmd: 保存配置
- config_cmd/SaveASCmd: 另存配置
- watch_cmd/AddCmd: 添加监视
- watch_cmd/DelCmd: 移除监视
- watch_cmd/ListCmd: 显示已监视目录的列表
- gen_cmd/GenCmd: 生成增强类和增强方法
- model/IEventDrivenModel：“事件驱动”的逻辑编排模型
- logger: 日志接口，略
config/IConfiguration.go
配置接口
package config
// IConfiguration defines system configuration interface
type IConfiguration interface {
GetProjectName() string
SetProjectName(string)
GetWatchPaths() []string
AddWatchPath(string)
DelWatchPath(string)
Save() error
SaveAS(string) error
}
command/ICmd.go
指令接口
package command
import "fmt"
// ICmd defines cli command interface
type ICmd interface {
fmt.Stringer
// Apply apply current command into use
Apply(ICmdContext) error
}
command/ICmdBuilder.go
指令构建器接口
package command
// ICmdBuilder parse input string and create an ICmd instance
type ICmdBuilder interface {
Build(string) (error, ICmd)
}
command/ICmdContext.go
指令执行上下文接口
package command
import "learning/gooop/spring/autogen/config"
// ICmdContext provides context info for all commands
type ICmdContext interface {
GetConfiguration() config.IConfiguration
}
config_cmd/SaveCmd.go
保存配置
package config_cmd
import (
"learning/gooop/spring/autogen/command"
)
// SaveCmd calls service.Save() to save current configuration, in JSON format
type SaveCmd int
// SaveCmdBuilder parse cli input and build a SaveCmd instance
type SaveCmdBuilder int
const gSaveCmdString = "config save"
var gSaveCmdInstance = new(SaveCmd)
func (me *SaveCmd) String() string {
return gSaveCmdString
}
func (me *SaveCmd) Apply(c command.ICmdContext) error {
// todo: fixme
panic("implements me")
}
func (me *SaveCmdBuilder) Build(line string) (error, command.ICmd) {
if line != gSaveCmdString {
return nil, nil
}
return nil, gSaveCmdInstance
}
config_cmd/SaveASCmd.go
另存配置
package config_cmd
import (
"errors"
"learning/gooop/spring/autogen/command"
"strings"
)
// SaveASCmd calls service.SaveAS() to save current config into specific file, in JSON format
type SaveASCmd struct {
file string
}
// SaveASCmdBuilder parse cli input and returns a SaveASCmd instance
type SaveASCmdBuilder int
const gSaveASCmdPrefix = "config saveas "
func (me *SaveASCmd) String() string {
return gSaveASCmdPrefix + me.file
}
func (me *SaveASCmd) Apply(c command.ICmdContext) error {
// todo: fixme
panic("implements me")
}
func (me *SaveASCmdBuilder) Build(line string) (error, command.ICmd) {
if !strings.HasPrefix(line, gSaveASCmdPrefix) {
return nil, nil
}
file := strings.TrimSpace(line[len(gSaveASCmdPrefix):])
if len(file) <= 0 {
return errors.New("empty file path"), nil
}
return nil, &SaveASCmd{file }
}
watch_cmd/AddCmd.go
添加监视
package watch_cmd
import (
"learning/gooop/spring/autogen/command"
"os"
"strings"
)
// AddCmd calls service.WatchAdd() to add dir to watch list
type AddCmd struct {
dir string
}
type AddCmdBuilder int
var gAddCmdPrefix = "watch add "
func (me *AddCmd) String() string {
return gAddCmdPrefix + me.dir
}
func (me *AddCmd) Apply(c command.ICmdContext) error {
// todo: fixme
panic("implements me")
}
func (me *AddCmdBuilder) Build(line string) (error, command.ICmd) {
// check prefix
if !strings.HasPrefix(line, gAddCmdPrefix) {
return nil, nil
}
// get dir
dir := strings.TrimSpace(line[len(gAddCmdPrefix):])
// check dir
_,e := os.Stat(dir)
if e != nil {
return e, nil
}
// ok
return nil, &AddCmd{dir }
}
watch_cmd/DelCmd.go
移除监视
package watch_cmd
import (
"learning/gooop/spring/autogen/command"
"os"
"strings"
)
// DelCmd calls service.WatchDel() to remove dir from watch list
type DelCmd struct {
dir string
}
type DelCmdBuilder int
var gDelCmdPrefix = "watch del "
func (me *DelCmd) String() string {
return gDelCmdPrefix + me.dir
}
func (me *DelCmd) Apply(c command.ICmdContext) error {
// todo: fixme
panic("implements me")
}
func (me *DelCmdBuilder) Build(line string) (error, command.ICmd) {
// check prefix
if !strings.HasPrefix(line, gDelCmdPrefix) {
return nil, nil
}
// get dir
dir := strings.TrimSpace(line[len(gAddCmdPrefix):])
// check dir
_,e := os.Stat(dir)
if e != nil {
return e, nil
}
// ok
return nil, &DelCmd{ dir }
}
watch_cmd/ListCmd.go
显示已监视目录的列表
package watch_cmd
import (
"learning/gooop/spring/autogen/command"
)
// ListCmd calls service.WatchList
type ListCmd int
// ListCmdBuilder parse cli input and try to build a ListCmd instance
type ListCmdBuilder int
const gListCmdString1 = "watch list"
const gListCmdString2 = "watch ls"
var gListCmdSingleton = new(ListCmd)
func (me *ListCmd) String() string {
return gListCmdString1
}
func (me *ListCmd) Apply(c command.ICmdContext) error {
// todo:
panic("implements me")
}
func (me *ListCmdBuilder) Build(line string) (error, command.ICmd) {
if line != gListCmdString1 && line != gListCmdString2 {
return nil, nil
}
return nil, gListCmdSingleton
}
gen_cmd/GenCmd.go
生成增强类和增强方法
package gen_cmd
import (
"learning/gooop/spring/autogen/command"
)
// GenCmd calls service.Gen() to generate enhanced code files at once
type GenCmd int
// GenCmdBuilder parse cli input and try to build a GenCmd instance
type GenCmdBuilder int
const gGenCmdString = "gen"
var gGenCmdSingleton = new(GenCmd)
func (me *GenCmd) String() string {
return gGenCmdString
}
func (me *GenCmd) Apply(c command.ICmdContext) error {
panic("implements me")
}
func (me *GenCmdBuilder) Build(line string) (error, command.ICmd) {
if line != gGenCmdString {
return nil, nil
}
return nil, gGenCmdSingleton
}
model/IEventDrivenModel.go
“事件驱动”的逻辑编排模型
package model
// IEventDrivenModel defines an event driven model for code arrangement
type IEventDrivenModel interface {
Hook(e string, handleFunc TEventHandleFunc)
Fire(e string, args ...interface{})
FireAsync(e string, args ...interface{})
}
type TEventHandleFunc func(e string, args ...interface{})
type TEventDrivenModel struct {
items map[string][]TEventHandleFunc
}
func (me *TEventDrivenModel) Hook(e string, handler TEventHandleFunc) {
if me.items == nil {
me.items = make(map[string][]TEventHandleFunc)
}
arr, ok := me.items[e]
if ok {
me.items[e] = append(arr, handler)
} else {
me.items[e] = []TEventHandleFunc{handler}
}
}
func (me *TEventDrivenModel) Fire(e string, args ...interface{}) {
if handlers, ok := me.items[e]; ok {
for _, it := range handlers {
it(e, args...)
}
}
}
func (me *TEventDrivenModel) FireAsync(e string, args ...interface{}) {
go me.Fire(e, args...)
}
（未完待续）
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