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package operator
import (
"context"
"fmt"
"goflink/core"
)
// MapFunc is business logic for user implement
type MapFunc[IN, OUT any] func(in IN) (OUT, error)
type MapOperator[IN, OUT any] struct {
userFunc MapFunc[IN, OUT]
}
func NewMapOperator[IN, OUT any](fn MapFunc[IN, OUT]) *MapOperator[IN, OUT] {
return &MapOperator[IN, OUT]{
userFunc: fn,
}
}
func (fo *MapOperator[IN, OUT]) Open(ctx context.Context) error {
return nil
}
func (fo *MapOperator[IN, OUT]) Process(ctx context.Context, record core.StreamRecord[IN], out Emitter[OUT]) error {
if record.Type != core.RecordData {
// watermark and barrier
return out.Emit(ctx, core.StreamRecord[OUT]{
Type: record.Type,
Key: record.Key,
Timestamp: record.Timestamp,
BarrierID: record.BarrierID,
})
}
outValue, err := fo.userFunc(record.Value)
if err != nil {
return fmt.Errorf("cannot process value %v: %w", record.Value, err)
}
return out.Emit(ctx, core.StreamRecord[OUT]{
Type: core.RecordData,
Key: record.Key,
Timestamp: record.Timestamp,
Value: outValue,
})
}
func (fo *MapOperator[IN, OUT]) Close(ctx context.Context) error {
return nil
}
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