[英]Go: Dynamic type cast/assertion of struct's with interface (to call methods and use struct commons)
我试图让我的代码变得更简洁,更清洁。 问题在于一个函数,它使用不同的structs
, implements
一个interface
。
在某些情况下,我需要model
变量来实现结构(rowModel的切片)([] rowModel),有时我需要使用接口中的方法。 代码并不简短,对不起。 所以我把主要评论放在下面的代码中。
这是界面:
type StatModel interface {
FilterData(Filter)
ClusterData(Filter)
CountDataForChart(string)[]ChartElement
GroupByTreeGroups(Filter)[]OrgPack
}
type StatRow interface {
Count( name string) float64
}
此接口是为方法调用创建的,并且可以缩短代码。 但是接口不能在OOP中将字段或结构作为Abstruct类。 其中一个模型在这里:
type NoaggModel []NoaggRow
type NoaggRow struct {
Date string
Hour int
Id_user int
Id_line float64
Id_region int
Id_tree_devision int
N_inb float64
N_out float64
N_hold float64
N_abandon float64
N_transfer float64
T_inb float64
T_out float64
T_hold float64
T_ring float64
T_acw float64
T_wait float64
}
type FcrModel []FcrRow
type FcrRow struct {
Date string
Hour int
Id_user int
Id_line float64
Id_region int
Id_tree_devision int
N_irr float64
N_inb float64
}
所以,我正在阅读频道,获得不同的结构,并尝试正确计算所有内容。 在这种情况下如何正确地进行类型断言和方法调用?
func receiveLightWork(org <-chan models.OrgPack, request ChartOptions) interface{} {
modelClusters := make(map[string][]models.OrgPack)
// here I fill data into modelClusters
output := make(map[string][]OrgStat)
// here I begin loop over clusters of different model types
for modelName, slice := range modelClusters {
//here I can't choose what to write
// model must be convertable to NoaggModel, that is []NoaggRow{}
// as others AcsiModel, FcrModel ...etc.
// Also model.ClusterData(customFilter) must be callable as it is in interface of common model
var model []interface{}
var rowModel interface{}
switch modelName {
case "noagg":
model = model.(models.NoaggModel)
rowModel = rowModel.(models.NoaggRow{})
case "acsi":
model = model.(models.AcsiModel)
rowModel = rowModel.(models.AcsiRow)
case "fcr24":
model = model.(models.FcrModel)
rowModel = rowModel.(models.FcrRow)
case "aic":
model = model.(models.AicModel)
rowModel = rowModel.(models.AicRow)
}
for _, el := range slice {
modelFields := reflect.ValueOf(&rowModel).Elem()
sliceFields := reflect.ValueOf(&el.SummorisedData).Elem()
fieldsTypes := modelFields.Type()
for i := 6; i < modelFields.NumField(); i++ {
fmt.Println(" model_field ", fieldsTypes.Field(i).Name )
modelField := modelFields.Field(i);
sliceField := sliceFields.Index(i-6) ;
modelField.Set(reflect.Value(sliceField));
}
id_line := sliceFields.Index(len(el.SummorisedData) - 1) ;
date := sliceFields.FieldByName("PackName");
modelFields.FieldByName("Id_line").Set(id_line)
modelFields.FieldByName("Date").Set(date)
// here append not works, because model is []interface{} and not []NoaggRow or others.
// Writes [non-interface type []interface {} on left]
model = append(model, rowModel)
}
// here I need to call interface method for model
model.ClusterData(customFilter) // now here is unresolved Reference 'ClusterData'
for _, mod := range model {
// here some common logick for creating data for chart output
}
}
return output
}
非常感谢所有帮助。 如有必要,我会回答有关此主题的每个问题。
修改了一些动态生成结构的东西。 现在所有人都在正确编译,直到我需要获取struct实例的地方。 它只看到界面..评论和代码更新在这里:
func typeSwitch(model string) (interface{}, interface{}){
switch model{
case "noagg":
fmt.Println("Model type:", model)
return &models.NoaggModel{}, &models.NoaggRow{}
case "acsi":
fmt.Println("Model type:", model)
return &models.AcsiModel{}, &models.AcsiRow{}
case "fcr24":
fmt.Println("Model type:", model)
return &models.FcrModel{}, &models.FcrRow{}
case "aic":
fmt.Println("Model type:", model)
return &models.AicModel{}, &models.AicRow{}
default:
fmt.Println("Unknown")
return false,false
}
}
func receiveLightWork(org <-chan models.OrgPack, request ChartOptions) interface{} {
modelClusters := make(map[string][]models.OrgPack)
for orgPack := range org {
// here I fill data into clusters
}
output := make(map[string][]OrgStat)
// here I need common code to put data from clusters in correct structures and call interface methods
for modelName, slice := range modelClusters {
model, rowModel := typeSwitch(modelName)
var data_slice []interface{}
for _, el := range slice {
modelFields := reflect.ValueOf(rowModel).Elem()
fieldsCounter := modelFields.NumField()
sliceFields := reflect.ValueOf(&el.SummorisedData).Elem()
sliceObjFields := reflect.ValueOf(&el).Elem()
fieldsTypes := modelFields.Type()
for i := 6; i < fieldsCounter; i++ {
fmt.Println(" model_field ", fieldsTypes.Field(i).Name )
modelField := modelFields.Field(i);
sliceField := sliceFields.Index(i-6) ;
modelField.Set(reflect.Value(sliceField));
}
id_line := sliceFields.Index(len(el.SummorisedData) - 1) ;
date := sliceObjFields.FieldByName("PackName");
modelFields.FieldByName("Id_line").Set(id_line)
modelFields.FieldByName("Date").Set(date)
fmt.Println("row_data : ", rowModel)
data_slice = append(data_slice, rowModel)
}
// here comes : invalid type assertion: data_slice.(model) (non-interface type []interface {} on left
dataModel := data_slice.(model)
// here I need correctly created instance of model
// (NoaggModel or FcrModel) with data inside its struct
// to work with it and call interface methods that are shown in interface above
}
return output
}
根据你如何跳过newItem
函数的前六个字段,看起来像这些属性:
type BaseModel struct {
Date string
Hour int
Id_user int
Id_line float64
Id_region int
Id_tree_devision int
}
对所有型号都很常见。 为什么不嵌入这些值?
有没有什么理由你的OrgPack
结构不能只保存nextIdLine int
值或者那些行? 我认为这可能会导致代码比使用反射和切片长度来计算行id值更清晰。
如果你做了以上两件事,你也可以轻松更换
func newItem(modelName string, el models.OrgPack) interface{}
同
func (el OrgPack) NewNoagg() Noagg
func (el OrgPack) NewFcr() Fcr
也许
type RowFactory interface { New(el OrgPack) StatRow }
type NoaggFactory struct{}
func (_ NoaggFactory) New(el OrgPack) StatRow
在后一种情况下,您可以将RowFactory
属性附加到OrgPack
而不是ModelName
,或者除了ModelName
之外,还可以生成正确的StatRow
值,而无需切换字符串值。
正如您所指出的那样,您在receiveLightWork
每个开关都基本相同:您创建一个新元素片段,以某种方式“集群”它们,格式化输出并返回它。
如上所述,可以通过类似Factory
的接口来创建切片。 ClusterData
已经是一种接口方法。 FormatOutput
可能应该是。
如果移动取决于数据与您合作为这些类型的方法类型的逻辑,我想应该是可以实现receiveLightWork
,看起来像这样 :
func receiveLightWork(org <-chan models.OrgPack, request ChartOptions) map[string][]OrgStat {
modelClusters := make(map[string][]models.OrgPack)
for orgPack := range org {
if model, ok := modelClusters[orgPack.ModelName]; ok {
modelClusters[orgPack.ModelName] = append(model, orgPack)
} else {
modelClusters[orgPack.ModelName] = []models.OrgPack{orgPack}
}
}
customFilter := request.Filters
customFilter.Cluster = "clusterDay"
output := make(map[string][]OrgStat)
for modelName, slice := range modelClusters {
if len(slice) == 0 {
continue
}
model := slice[0].ModelFactory.New()
for _, el := range slice {
model.Add(el.RowFactory.New(el))
}
model.ClusterData(customFilter)
for sourceName, charts := range request.Charts {
output = model.FormatOutput(output, sourceName, charts)
}
}
return output
}
也许这是愚蠢的方式,因为我不知道更好的方法。
这里是您可以使用的示例代码(仅此草稿)。
首先创建新函数将[] interface {}转换为模型:
func GetModel(modelName string, data []interface{}) interface{} {
switch modelName {
case "noagg" :
m := make(NoaggModel, len(data))
for i, v := range data {
m[i] = v.(NoaggRow)
}
return m
case .....
//and case so on
}
}
你的代码“dataModel:= data_slice。(model)”替换如下:
dataModel := GetModel(modelName, data_slice)
//now your dataModel is ready to convert to StatModel
if statModel, ok := dataModel.(StatModel); ok {
statModel.FilterData(?) //just example
}
也许这可以给你一些想法。
我相信你已经知道了,但是使用这么多interface{}
实体会使代码变得难以阅读,并且失去了使用类型安全语言的许多优点。
如果有时间稍微重新设计一下,我会质疑接口类型的通道真的是必要的假设。 也许您可以使用多个渠道。
然后,当你从你的频道中读到时,你会写:
for !done {
select {
case model := <- noaggModelChan:
doThingsWithNoaggModel(model)
case model := <- fcrModelChan:
doThingsWithFcrModel(model)
case done = <- doneChan:
continue
}
}
Stackoverflow
站点上的2个答案以及Gophers对Slack
聊天的许多帮助和支持。 正如我在晚上与更熟练的开发人员的会谈中所认识到的那样,我试图创建在OOP语言中常用的“泛型”(例如php的最新版本)。
我想(并且仍然想要)创建一个紧凑的方法,它可以通过其类型的名称与任何模型结构很好地协作。 但即使使用reflection
我也没有找到解决方案,因为有可能不能输入确切的struct type
来进行断言。
所以..我的代码变短了,但我没有达到主要目标:
“方法的代码不应该取决于可能出现的模型结构的数量。”
这是我自己的目标,我不是在做一些人的任务。 只有我自己的优化。 但失败的事实令人悲伤。 所以我的,不是最终的,但最后一个版本是这样的:
func newItem(modelName string, el models.OrgPack) interface{} {
var item models.StatRow
switch modelName {
case "noagg":
item = &models.NoaggRow{}
case "fcr24":
item = &models.FcrRow{}
case "acsi":
item = &models.AcsiRow{}
case "aic":
item = &models.AicRow{}
case "aux":
item = &models.AuxRow{}
case "cti":
item = &models.CtiRow{}
case "srv":
item = &models.SrvRow{}
case "sale":
item = &models.SaleRow{}
case "pds":
item = &models.PdsRow{}
case "wfm":
item = &models.WfmRow{}
}
modelFields := reflect.ValueOf(item).Elem()
fieldsCounter := modelFields.NumField()
sliceFields := reflect.ValueOf(&el.SummorisedData).Elem()
sliceObjFields := reflect.ValueOf(&el).Elem()
fieldsTypes := modelFields.Type()
for i := 6; i < fieldsCounter; i++ {
fmt.Println(" model_field ", fieldsTypes.Field(i).Name)
modelField := modelFields.Field(i);
sliceField := sliceFields.Index(i - 6);
modelField.Set(reflect.Value(sliceField));
}
id_line := sliceFields.Index(len(el.SummorisedData) - 1);
date := sliceObjFields.FieldByName("PackName");
modelFields.FieldByName("Id_line").Set(id_line)
modelFields.FieldByName("Date").Set(date)
return item
}
func formatOutput(output map[string][]OrgStat, sourceName string, modelName string, charts []Chart, mod models.StatRow, cluster string) map[string][]OrgStat {
if sourceName == modelName {
var stats []OrgStat
for _, chart := range charts {
stats = append(stats, OrgStat{Name:chart.Name, Value: mod.Count(chart.Name)})
}
_, group_exist := output[cluster]
if group_exist {
inserted_stat := output[cluster]
output[cluster] = append(stats, inserted_stat...)
}else {
output[cluster] = stats
}
}
return output
}
func receiveLightWork(org <-chan models.OrgPack, request ChartOptions) interface{} {
modelClusters := make(map[string][]models.OrgPack)
for orgPack := range org {
_, ok := modelClusters[orgPack.ModelName]
if ok {
model := modelClusters[orgPack.ModelName]
model = append(model, orgPack)
modelClusters[orgPack.ModelName] = model
}else {
var modelSlice []models.OrgPack
modelSlice = append(modelSlice, orgPack)
modelClusters[orgPack.ModelName] = modelSlice
}
}
output := make(map[string][]OrgStat)
for modelName, slice := range modelClusters {
switch modelName {
case "noagg":
model := models.NoaggModel{}
for _, el := range slice {
newElement := newItem(modelName, el)
model = append(model, *(newElement.(*models.NoaggRow)))
}
customFilter := request.Filters
customFilter.Cluster = "clusterDay"
model.ClusterData(customFilter)
for _, mod := range model {
for sourceName, charts := range request.Charts {
output = formatOutput(output, sourceName, modelName, charts, mod, mod.Date)
}
}
case "acsi":
model := models.AcsiModel{}
for _, el := range slice {
newElement := newItem(modelName, el)
model = append(model, *(newElement.(*models.AcsiRow)))
}
customFilter := request.Filters
customFilter.Cluster = "clusterDay"
model.ClusterData(customFilter)
for _, mod := range model {
for sourceName, charts := range request.Charts {
output = formatOutput(output, sourceName, modelName, charts, mod, mod.Date)
}
}
case "fcr24":
model := models.FcrModel{}
for _, el := range slice {
newElement := newItem(modelName, el)
model = append(model, *(newElement.(*models.FcrRow)))
}
customFilter := request.Filters
customFilter.Cluster = "clusterDay"
model.ClusterData(customFilter)
for _, mod := range model {
for sourceName, charts := range request.Charts {
output = formatOutput(output, sourceName, modelName, charts, mod, mod.Date)
}
}
case "aic":
model := models.AicModel{}
for _, el := range slice {
newElement := newItem(modelName, el)
model = append(model, *(newElement.(*models.AicRow)))
}
customFilter := request.Filters
customFilter.Cluster = "clusterDay"
model.ClusterData(customFilter)
for _, mod := range model {
for sourceName, charts := range request.Charts {
output = formatOutput(output, sourceName, modelName, charts, mod, mod.Date)
}
}
case "aux":
model := models.AuxModel{}
for _, el := range slice {
newElement := newItem(modelName, el)
model = append(model, *(newElement.(*models.AuxRow)))
}
customFilter := request.Filters
customFilter.Cluster = "clusterDay"
model.ClusterData(customFilter)
for _, mod := range model {
for sourceName, charts := range request.Charts {
output = formatOutput(output, sourceName, modelName, charts, mod, mod.Date)
}
}
case "cti":
model := models.CtiModel{}
for _, el := range slice {
newElement := newItem(modelName, el)
model = append(model, *(newElement.(*models.CtiRow)))
}
customFilter := request.Filters
customFilter.Cluster = "clusterDay"
model.ClusterData(customFilter)
for _, mod := range model {
for sourceName, charts := range request.Charts {
output = formatOutput(output, sourceName, modelName, charts, mod, mod.Date)
}
}
case "srv":
model := models.SrvModel{}
for _, el := range slice {
newElement := newItem(modelName, el)
model = append(model, *(newElement.(*models.SrvRow)))
}
customFilter := request.Filters
customFilter.Cluster = "clusterDay"
model.ClusterData(customFilter)
for _, mod := range model {
for sourceName, charts := range request.Charts {
output = formatOutput(output, sourceName, modelName, charts, mod, mod.Date)
}
}
case "sale":
model := models.SaleModel{}
for _, el := range slice {
newElement := newItem(modelName, el)
model = append(model, *(newElement.(*models.SaleRow)))
}
customFilter := request.Filters
customFilter.Cluster = "clusterDay"
model.ClusterData(customFilter)
for _, mod := range model {
for sourceName, charts := range request.Charts {
output = formatOutput(output, sourceName, modelName, charts, mod, mod.Date)
}
}
case "pds":
model := models.PdsModel{}
for _, el := range slice {
newElement := newItem(modelName, el)
model = append(model, *(newElement.(*models.PdsRow)))
}
customFilter := request.Filters
customFilter.Cluster = "clusterDay"
model.ClusterData(customFilter)
for _, mod := range model {
for sourceName, charts := range request.Charts {
output = formatOutput(output, sourceName, modelName, charts, mod, mod.Date)
}
}
case "wfm":
model := models.WfmModel{}
for _, el := range slice {
newElement := newItem(modelName, el)
model = append(model, *(newElement.(*models.WfmRow)))
}
customFilter := request.Filters
customFilter.Cluster = "clusterDay"
model.ClusterData(customFilter)
for _, mod := range model {
for sourceName, charts := range request.Charts {
output = formatOutput(output, sourceName, modelName, charts, mod, mod.Date)
}
}
}
}
return output
}
正如您所看到的,这些方法的长度直接取决于模型的数量,我无法将此代码放入模型中,因为它是为类型转换而创建的,以便为以后的数学创建正确的结构。
如果有人有任何想法,如何达到这最后的目标( receiveLightWork
方法的代码不依赖于模型数量),我会很高兴听到它!
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