Golang语言情怀-第26期 Go 语言设计模式 职责链

ackage ChainofResponsibilityPattern

const (
    INFO = iota + 1
    DEBUG
    ERROR
)

type Logger interface {
    LogMessage(level int, message string, logger Logger)
    write(message string)
}

type AbstractLogger struct {
    level      int
    nextLogger Logger
}

func (s *AbstractLogger) write(message string) {

}

func (s *AbstractLogger) SetNextLogger(logger Logger) {
    s.nextLogger = logger
}

func (s *AbstractLogger) LogMessage(level int, message string, logger Logger) {
    if s.level <= level {
        logger.write(message)
    } else {
        if s.nextLogger != nil {
            s.nextLogger.LogMessage(level, message, s.nextLogger)
        }
    }
}

package ChainofResponsibilityPattern

import "fmt"

type ConsoleLogger struct {
    abstractLogger AbstractLogger
}

func (c *ConsoleLogger) write(message string) {
    fmt.Println("Standard Console::Logger: " + message)
}

func (c *ConsoleLogger) LogMessage(level int, message string, logger Logger) {
    c.abstractLogger.LogMessage(level, message, c)
}

package ChainofResponsibilityPattern

import "fmt"

type ErrorLogger struct {
    abstractLogger AbstractLogger
}

func (e *ErrorLogger) write(message string) {
    fmt.Println("Error Console::Logger: " + message)
}

func (e *ErrorLogger) LogMessage(level int, message string, logger Logger) {
    e.abstractLogger.LogMessage(level, message, e)
}

package ChainofResponsibilityPattern

import "fmt"

type FileLogger struct {
    abstractLogger AbstractLogger
}

func (f *FileLogger) write(message string) {
    fmt.Println("File::Logger: " + message)
}

func (f *FileLogger) LogMessage(level int, message string, logger Logger) {
    f.abstractLogger.LogMessage(level, message, f)
}

package ChainofResponsibilityPattern

func TestChainofResponsibilityPattern() Logger {
    errorLogger := new(ErrorLogger)
    errorLogger.abstractLogger.level = ERROR

    fileLogger := new(FileLogger)
    fileLogger.abstractLogger.level = DEBUG

    consoleLogger := new(ConsoleLogger)
    consoleLogger.abstractLogger.level = INFO

    errorLogger.abstractLogger.SetNextLogger(fileLogger)
    fileLogger.abstractLogger.SetNextLogger(consoleLogger)

    return errorLogger
}

func testChainofResponsibilityPattern() {
    logger := ChainofResponsibilityPattern.TestChainofResponsibilityPattern()

    logger.LogMessage(ChainofResponsibilityPattern.INFO, "This is an information.", nil)

    logger.LogMessage(ChainofResponsibilityPattern.DEBUG, "This is a debug level information.", nil)

    logger.LogMessage(ChainofResponsibilityPattern.ERROR, "This is an error information.", nil)
}

Standard Console::Logger: This is an information.
File::Logger: This is a debug level information.
Error Console::Logger: This is an error information.

package chainofresponsibility

import "fmt"

type Request struct {
    RequestType    string
    RequestContent string
    Number         int
}

type Manager interface {
    SetNext(next Manager)
    RequestHandler(request Request)
}

type CommonManager struct {
    Manager
    Name string
}

func (cm *CommonManager) SetNext(next Manager) {
    cm.Manager = next
}

func (cm *CommonManager) RequestHandler(request Request) {
    if request.RequestType == "请假" && request.Number <= 2 {
        fmt.Printf("%s: %s 数量 %d 已批准\n", cm.Name, request.RequestContent, request.Number)
    } else {
        if cm.Manager != nil {
            cm.Manager.RequestHandler(request)
        }
    }
}

type MajorManager struct {
    Manager
    Name string
}

func (mm *MajorManager) SetNext(next Manager) {
    mm.Manager = next
}

func (mm *MajorManager) RequestHandler(request Request) {
    if request.RequestType == "请假" && request.Number <= 5 {
        fmt.Printf("%s: %s 数量 %d 已批准\n", mm.Name, request.RequestContent, request.Number)
    } else {
        if mm.Manager != nil {
            mm.Manager.RequestHandler(request)
        }
    }
}

type GeneralManager struct {
    Manager
    Name string
}

func (gm *GeneralManager) SetNext(next Manager) {
    gm.Manager = next
}

func (gm *GeneralManager) RequestHandler(request Request) {
    if request.RequestType == "请假" {
        fmt.Printf("%s: %s 数量 %d 已批准\n", gm.Name, request.RequestContent, request.Number)
    } else if request.RequestType == "加薪" && request.Number <= 500 {
        fmt.Printf("%s: %s 数量 %d 已批准\n", gm.Name, request.RequestContent, request.Number)
    } else if request.RequestType == "加薪" && request.Number > 500 {
        fmt.Printf("%s: %s 数量 %d 再说吧\n", gm.Name, request.RequestContent, request.Number)
    }
}

func main() {
    wenxiang := &chainofresponsibility.CommonManager{
        Name: "文祥",
    }
    xiaoyun := &chainofresponsibility.MajorManager{
        Name: "晓云",
    }
    yuanlei := &chainofresponsibility.GeneralManager{
        Name: "苑磊",
    }
    wenxiang.SetNext(xiaoyun)
    xiaoyun.SetNext(yuanlei)

    request := chainofresponsibility.Request{
        RequestType:    "请假",
        RequestContent: "小菜请假",
        Number:         2,
    }
    wenxiang.RequestHandler(request)

    request = chainofresponsibility.Request{
        RequestType:    "请假",
        RequestContent: "小菜请假",
        Number:         5,
    }
    wenxiang.RequestHandler(request)

    request = chainofresponsibility.Request{
        RequestType:    "加薪",
        RequestContent: "小菜请求加薪",
        Number:         500,
    }
    wenxiang.RequestHandler(request)

    request = chainofresponsibility.Request{
        RequestType:    "加薪",
        RequestContent: "小菜请求加薪",
        Number:         1000,
    }
    wenxiang.RequestHandler(request)
}