public class BoundedReadFromUnboundedSource<T> extends PTransform<PBegin,PCollection<T>>
PTransform that reads a bounded amount of data from an UnboundedSource,
specified as one or both of a maximum number of elements or a maximum period of time to read.name| Modifier and Type | Method and Description |
|---|---|
PCollection<T> |
expand(PBegin input)
Override this method to specify how this
PTransform should be expanded
on the given InputT. |
BoundedSource<ValueWithRecordId<T>> |
getAdaptedSource()
Returns an adapted
BoundedSource wrapping the underlying UnboundedSource,
with the specified bounds on number of records and read time. |
protected Coder<T> |
getDefaultOutputCoder()
Returns the default
Coder to use for the output of this
single-output PTransform. |
java.lang.String |
getKindString()
Returns the name to use by default for this
PTransform
(not including the names of any enclosing PTransforms). |
void |
populateDisplayData(DisplayData.Builder builder)
Register display data for the given transform or component.
|
BoundedReadFromUnboundedSource<T> |
withMaxNumRecords(long maxNumRecords)
Returns a new
BoundedReadFromUnboundedSource that reads a bounded amount
of data from the given UnboundedSource. |
BoundedReadFromUnboundedSource<T> |
withMaxReadTime(Duration maxReadTime)
Returns a new
BoundedReadFromUnboundedSource that reads a bounded amount
of data from the given UnboundedSource. |
getAdditionalInputs, getDefaultOutputCoder, getDefaultOutputCoder, getName, toString, validatepublic BoundedReadFromUnboundedSource<T> withMaxNumRecords(long maxNumRecords)
BoundedReadFromUnboundedSource that reads a bounded amount
of data from the given UnboundedSource. The bound is specified as a number
of records to read.
This may take a long time to execute if the splits of this source are slow to read records.
public BoundedReadFromUnboundedSource<T> withMaxReadTime(Duration maxReadTime)
BoundedReadFromUnboundedSource that reads a bounded amount
of data from the given UnboundedSource. The bound is specified as an amount
of time to read for. Each split of the source will read for this much time.@Experimental public BoundedSource<ValueWithRecordId<T>> getAdaptedSource()
BoundedSource wrapping the underlying UnboundedSource,
with the specified bounds on number of records and read time.public PCollection<T> expand(PBegin input)
PTransformPTransform should be expanded
on the given InputT.
NOTE: This method should not be called directly. Instead apply the
PTransform should be applied to the InputT using the apply
method.
Composite transforms, which are defined in terms of other transforms, should return the output of one of the composed transforms. Non-composite transforms, which do not apply any transforms internally, should return a new unbound output and register evaluators (via backend-specific registration methods).
expand in class PTransform<PBegin,PCollection<T>>protected Coder<T> getDefaultOutputCoder()
PTransformCoder to use for the output of this
single-output PTransform.
By default, always throws
getDefaultOutputCoder in class PTransform<PBegin,PCollection<T>>public java.lang.String getKindString()
PTransformPTransform
(not including the names of any enclosing PTransforms).
By default, returns the base name of this PTransform's class.
The caller is responsible for ensuring that names of applied
PTransforms are unique, e.g., by adding a uniquifying
suffix when needed.
getKindString in class PTransform<PBegin,PCollection<T>>public void populateDisplayData(DisplayData.Builder builder)
PTransformpopulateDisplayData(DisplayData.Builder) is invoked by Pipeline runners to collect
display data via DisplayData.from(HasDisplayData). Implementations may call
super.populateDisplayData(builder) in order to register display data in the current
namespace, but should otherwise use subcomponent.populateDisplayData(builder) to use
the namespace of the subcomponent.
By default, does not register any display data. Implementors may override this method to provide their own display data.
populateDisplayData in interface HasDisplayDatapopulateDisplayData in class PTransform<PBegin,PCollection<T>>builder - The builder to populate with display data.HasDisplayData