48 lines
1.1 KiB
Go
48 lines
1.1 KiB
Go
package collectors
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// AveragingFloat64 统计结果集平均值
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type AveragingFloat64 struct {
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Mapper func(interface{}) float64
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}
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type aveMidResult struct {
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Sum float64
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Count int
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}
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// Supplier 提供容器
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func (ave *AveragingFloat64) Supplier() func() interface{} {
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return func() interface{} {
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return aveMidResult{Sum: 0, Count: 0}
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}
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}
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// Accumulator 处理函数
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func (ave *AveragingFloat64) Accumulator() func(interface{}, interface{}) interface{} {
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return func(identity interface{}, element interface{}) interface{} {
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mid := identity.(aveMidResult)
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mid.Count++
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mid.Sum += ave.Mapper(element)
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return mid
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}
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}
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// Combiner 组装结果
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func (ave *AveragingFloat64) Combiner() func(interface{}, interface{}) interface{} {
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return func(a interface{}, b interface{}) interface{} {
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midA := a.(aveMidResult)
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midB := b.(aveMidResult)
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midA.Sum += midB.Sum
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midA.Count += midB.Count
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return midA
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}
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}
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// Finisher 收尾处理
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func (ave *AveragingFloat64) Finisher() func(interface{}) interface{} {
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return func(identity interface{}) interface{} {
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mid := identity.(aveMidResult)
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return mid.Sum / float64(mid.Count)
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}
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}
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