64 lines
1.5 KiB
Go
64 lines
1.5 KiB
Go
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package collectors
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import . "github.com/go-func/stream"
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// PartitioningBy 按照指定的分区
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type PartitioningBy struct {
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Predicate func(interface{}) bool
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DownStream Collector
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}
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// Supplier 提供容器
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func (p *PartitioningBy) Supplier() func() interface{} {
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return func() interface{} {
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return make(map[bool][]interface{})
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}
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}
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// Accumulator 处理函数
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func (p *PartitioningBy) Accumulator() func(interface{}, interface{}) interface{} {
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return func(identity interface{}, element interface{}) interface{} {
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ret := identity.(map[bool][]interface{})
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k := p.Predicate(element)
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if value, ok := ret[k]; ok {
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ret[k] = append(value, element)
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} else {
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list := make([]interface{}, 1)
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list[0] = element
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ret[k] = list
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}
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return ret
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}
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}
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// Combiner 组装结果
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func (p *PartitioningBy) Combiner() func(interface{}, interface{}) interface{} {
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return func(a interface{}, b interface{}) interface{} {
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mapA := a.(map[bool][]interface{})
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mapB := b.(map[bool][]interface{})
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for k, v := range mapB {
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if value, ok := mapA[k]; ok {
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mapA[k] = append(value, v...)
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} else {
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mapA[k] = v
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}
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}
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return mapA
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}
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}
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// Finisher 收尾处理
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func (p *PartitioningBy) Finisher() func(interface{}) interface{} {
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return func(identity interface{}) interface{} {
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if p.DownStream != nil {
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result := identity.(map[bool][]interface{})
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downStreamResult := make(map[bool]interface{})
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for k, v := range result {
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downStreamResult[k] = NewStream(v).Collect(p.DownStream)
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}
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return downStreamResult
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}
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return identity
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}
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}
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