@Experimental public interface PushdownProjector<InputT extends PInput>
PTransform
that can execute a projection.
Typically this interface will be implemented by a reader PTransform
that is capable of
pushing down projection to an external source. For example, SchemaIO.buildReader()
may
return a PushdownProjector
to which a projection may be applied later.
Modifier and Type | Method and Description |
---|---|
boolean |
supportsFieldReordering()
Returns true if this instance can do a projection that returns fields in a different order than
the projection's inputs.
|
PTransform<InputT,PCollection<Row>> |
withProjectionPushdown(FieldAccessDescriptor fieldAccessDescriptor)
Returns a
PTransform that will execute the projection specified by the FieldAccessDescriptor . |
PTransform<InputT,PCollection<Row>> withProjectionPushdown(FieldAccessDescriptor fieldAccessDescriptor)
PTransform
that will execute the projection specified by the FieldAccessDescriptor
.boolean supportsFieldReordering()