手擼golang 仿spring ioc/aop 之3

手擼golang 仿spring ioc/aop 之3

緣起

最近閱讀 [Offer來了：Java面試核心知識點精講（框架篇）] (王磊 , 2020.6)
本系列筆記擬採用golang練習之
Talk is cheap, show me the code.

Spring

Spring基於J2EE技術實現了一套輕量級的
Java Web Service系統應用框架。
它有不少優秀的特性，不少公司都選擇把
Spring做爲產品或項目的基礎開發架構。

Spring的主要特性包括：
1. 輕量
2. 控制反轉（Inversion of Control, IoC）
3. 面向容器
4. 面向切面（AspectOriented Programming, AOP）
5. 框架靈活

源碼gitee地址：
https://gitee.com/ioly/learning.gooop

原文連接：
https://my.oschina.net/ioly

目標

• 參考spring經常使用註解，使用golang編寫「基於註解的靜態代碼加強器/生成器」

  • 配置： ComponentScan，Configuration, Bean
  • Bean聲明：Component, Service, Controller
  • Bean注入：Autowried
  • AOP註解：Before, After, Around, PointCut

子目標（Day 3）

• 添加ProjectCmd以支持項目定義
• 添加文本掃描的輔助類：Chars.go, Tokens.go
• 定義代碼生成服務接口ICodingService及其支撐接口

設計

• command/ProjectCmd: 項目定義指令
• common/Chars: 字符識別輔助類
• common/Tokens: 組合文本識別輔助類
• service/ICodingService: 代碼生成服務接口
• service/iCodingContext: 代碼生成上下文
• service/iCodingState：狀態模式下的服務狀態
• service/iCmdRunner：定義指令執行器接口，具體執行擬走責任鏈模式以便擴展
• service/tInitialState：默認的服務狀態

command/ProjectCmd.go

項目定義指令

package project_cmd

import (
    "errors"
    "fmt"
    "learning/gooop/spring/autogen/command"
    "learning/gooop/spring/autogen/common"
    "os"
    "strings"
)

// ProjectCmd defines a project with name and dir
type ProjectCmd struct {
    name string
    dir string
}

// ProjectCmdBuilder parses cli input and creates a ProjectCmd instance
type ProjectCmdBuilder int

const gProjectCmdPrefix = "project "
var gErrorInvalidProjectCmd = errors.New("invalid project cmd")

func (me *ProjectCmd) String() string {
    return fmt.Sprintf("project %s %s", me.name, me.dir)
}

func (me *ProjectCmd) Apply(ctx command.ICmdContext) error {
    panic("implements me")
}

func (me *ProjectCmdBuilder) Build(line string) (error, command.ICmd) {
    if !common.Tokens.MatchString(line, gProjectCmdPrefix) {
        return nil, nil
    }

    line = strings.TrimSpace(line[len(gProjectCmdPrefix):])
    b,name := common.Tokens.MatchIdentifier(line)
    if !b {
        return gErrorInvalidProjectCmd, nil
    }

    line = line[len(name):]
    b, spaces := common.Tokens.MatchSpaces(line)
    if !b {
        return gErrorInvalidProjectCmd, nil
    }

    line = line[len(spaces):]
    b, dir := common.Tokens.MatchDir(line)
    if !b {
        return gErrorInvalidProjectCmd, nil
    }
    _,e := os.Stat(dir)
    if e != nil {
        return e, nil
    }

    return nil, &ProjectCmd{ name, dir }
}

common/Chars.go

字符識別輔助類

package common


type tChars int

var Chars = new(tChars)

func (me *tChars) IsSpace(it rune) bool {
    switch it {
    case ' ':
        return true
    case '\t':
        return true
    case '\r':
        return true
    case '\n':
        return true
    }

    return false
}


func (me *tChars) Is09(it rune) bool {
    return it >= '0' && it <= '9'
}

func (me *tChars) Is19(it rune) bool {
    return it >= '1' && it <= '9'
}

func (me *tChars) IsLetter(it rune) bool {
    return (it >= 'a' && it <= 'z') || (it >= 'A' && it <= 'Z')
}

func (me *tChars) IsUnderscore(it rune) bool {
    return it == '_'
}

func (me *tChars) IsLB(it rune) bool {
    return it == '('
}

func (me *tChars) IsRB(it rune) bool {
    return it == ')'
}

func (me *tChars) IsChar(it rune, args... rune) bool {
    for _,v := range args {
        if v == it {
            return true
        }
    }
    return false
}

func (me *tChars) IsSQuote(it rune) bool {
    return me.IsChar(it, '\'')
}

func (me *tChars) IsDQuote(it rune) bool {
    return me.IsChar(it, '"')
}

func (me *tChars) IsRSplash(it rune) bool {
    return me.IsChar(it, '\\')
}

func (me *tChars) IsLSplash(it rune) bool {
    return me.IsChar(it, '/')
}

common/Tokens.go

組合文本識別輔助類

package common

import (
    "regexp"
    "strings"
    "sync"
)

type tTokens struct {
    cache map[string]*regexp.Regexp
    rwmutex *sync.RWMutex
}

var Tokens = newTokensLib()

func newTokensLib() *tTokens {
    it := new(tTokens)
    it.init()
    return it
}

func (me *tTokens) init() {
    me.cache = make(map[string]*regexp.Regexp)
    me.rwmutex = new(sync.RWMutex)
}

func (me *tTokens) MatchString(s string, p string) bool {
    return strings.HasPrefix(s, p)
}

func (me *tTokens) MatchRegexp(s string, p string) (bool, string) {
    me.rwmutex.RLock()
    r,ok := me.cache[p]
    me.rwmutex.RUnlock()

    if !ok {
        me.rwmutex.Lock()
        if r,ok = me.cache[p];!ok {
            r,_ = regexp.Compile(p)
        }
        me.rwmutex.Unlock()
    }

    if r == nil {
        return false, ""
    }

    if !r.MatchString(s) {
        return false, ""
    }

    return true, r.FindString(s)
}

func (me *tTokens) MatchIdentifier(s string) (bool, string) {
    return me.MatchRegexp(s, "^[_a-zA-Z]\\w{0,99}}")
}

func (me *tTokens) MatchSpaces(s string) (bool, string) {
    return me.MatchRegexp(s, "^\\s+")
}

func (me *tTokens) MatchDir(s string) (bool, string) {
    b,s := me.MatchRegexp(s, "^([a-zA-Z]\\:)?([\\\\/][^\\s/:*?<>|\\\"\\\\]+)+[\\/]?")
    if b {
        return b,s
    }

    b,s = me.MatchRegexp(s, "^\\\"([a-zA-Z]\\:)?([\\\\/][^/:*?<>|\\\"\\\\]+)+[\\/]?\\\"")
    if b {
        return b,s
    }

    b,s = me.MatchRegexp(s, "^'([a-zA-Z]\\:)?([\\\\/][^'/:*?<>|\\\"\\\\]+)+[\\/]?'")
    if b {
        return b,s
    }

    return false, ""
}

service/ICodingService.go

代碼生成服務接口

package service

type ICodingService interface {
    iCmdRunner

    State() iCodingState
    Start()
}

service/iCodingContext.go

代碼生成上下文

package service

// iCodingContext provides context info for iCodingState instance
type iCodingContext interface {
    HandleStateChanged(state iCodingState)
}

service/iCodingState.go

狀態模式下的服務狀態

package service

type iCodingState interface {
    iCmdRunner
}

service/iCmdRunner.go

定義指令執行器接口，具體執行擬走責任鏈模式以便擴展

package service

import "learning/gooop/spring/autogen/command"

// iCmdRunner runs a user cmd
type iCmdRunner interface {
    Run(cmd command.ICmd) error
}

service/tInitialState.go

默認的服務狀態

package service

import (
    "errors"
    "learning/gooop/spring/autogen/command"
)

// tInitialState is the default state for a coding service
// it will only accept ProjectCmd
type tInitialState struct {
    context iCodingContext
}

func newInitialState(c iCodingContext) iCodingState {
    it := new(tInitialState)
    it.init(c)
    return it
}

func (me *tInitialState) init(c iCodingContext) {
    me.context = c
}

var gErrorProjectDefineRequired = errors.New("project not defined: project <name> <dir>")


func (me *tInitialState) Run(cmd command.ICmd) error {
    panic("implement me")
}

（未完待續）