public interface Transform
TransformSpec
. Transforms allow adding new fields to input rows. Each
one has a "name" (the name of the new field) which can be referred to by DimensionSpecs, AggregatorFactories, etc.
Each also has a "row function", which produces values for this new field based on looking at the entire input row.
If a transform has the same name as a field in an input row, then it will shadow the original field. Transforms
that shadow fields may still refer to the fields they shadow. This can be used to transform a field "in-place".
Transforms do have some limitations. They can only refer to fields present in the actual input rows; in particular,
they cannot refer to other transforms. And they cannot remove fields, only add them. However, they can shadow a
field with another field containing all nulls, which will act similarly to removing the field.Modifier and Type | Method and Description |
---|---|
String |
getName()
Returns the field name for this transform.
|
RowFunction |
getRowFunction()
Returns the function for this transform.
|
String getName()
RowFunction getRowFunction()
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