org.apache.beam.sdk.io

Class AvroIO.Read<T>

java.lang.Object

org.apache.beam.sdk.transforms.PTransform<PBegin,PCollection<T>>

org.apache.beam.sdk.io.AvroIO.Read<T>

All Implemented Interfaces:

java.io.Serializable, HasDisplayData

Enclosing class:

AvroIO

public abstract static class AvroIO.Read<T>
extends PTransform<PBegin,PCollection<T>>

Implementation of AvroIO.read(java.lang.Class<T>) and AvroIO.readGenericRecords(org.apache.avro.Schema).

See Also:

Serialized Form

Field Summary

Fields inherited from class org.apache.beam.sdk.transforms.PTransform

name

Constructor Summary

Constructors

Constructor and Description
Read()

Method Summary

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.
AvroIO.Read<T>	from(java.lang.String filepattern) Like from(ValueProvider).
AvroIO.Read<T>	from(ValueProvider<java.lang.String> filepattern) Reads from the given filename or filepattern.
void	populateDisplayData(DisplayData.Builder builder) Register display data for the given transform or component.
AvroIO.Read<T>	watchForNewFiles(Duration pollInterval, Watch.Growth.TerminationCondition<java.lang.String,?> terminationCondition) Continuously watches for new files matching the filepattern, polling it at the given interval, until the given termination condition is reached.
AvroIO.Read<T>	withEmptyMatchTreatment(EmptyMatchTreatment treatment) Configures whether or not a filepattern matching no files is allowed.
AvroIO.Read<T>	withHintMatchesManyFiles() Hints that the filepattern specified in from(String) matches a very large number of files.
AvroIO.Read<T>	withMatchConfiguration(FileIO.MatchConfiguration matchConfiguration) Sets the FileIO.MatchConfiguration.

Methods inherited from class org.apache.beam.sdk.transforms.PTransform

compose, getAdditionalInputs, getDefaultOutputCoder, getDefaultOutputCoder, getDefaultOutputCoder, getKindString, getName, toString, validate

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

Read

public Read()

Method Detail

from

public AvroIO.Read<T> from(ValueProvider<java.lang.String> filepattern)

Reads from the given filename or filepattern.

If it is known that the filepattern will match a very large number of files (at least tens of thousands), use withHintMatchesManyFiles() for better performance and scalability.

from

public AvroIO.Read<T> from(java.lang.String filepattern)

Like from(ValueProvider).

withMatchConfiguration

public AvroIO.Read<T> withMatchConfiguration(FileIO.MatchConfiguration matchConfiguration)

Sets the FileIO.MatchConfiguration.

withEmptyMatchTreatment

public AvroIO.Read<T> withEmptyMatchTreatment(EmptyMatchTreatment treatment)

Configures whether or not a filepattern matching no files is allowed.

watchForNewFiles

@Experimental(value=SPLITTABLE_DO_FN)
public AvroIO.Read<T> watchForNewFiles(Duration pollInterval,
                                                                             Watch.Growth.TerminationCondition<java.lang.String,?> terminationCondition)

Continuously watches for new files matching the filepattern, polling it at the given interval, until the given termination condition is reached. The returned PCollection is unbounded.

This works only in runners supporting Experimental.Kind.SPLITTABLE_DO_FN.

withHintMatchesManyFiles

public AvroIO.Read<T> withHintMatchesManyFiles()

Hints that the filepattern specified in from(String) matches a very large number of files.

This hint may cause a runner to execute the transform differently, in a way that improves performance for this case, but it may worsen performance if the filepattern matches only a small number of files (e.g., in a runner that supports dynamic work rebalancing, it will happen less efficiently within individual files).

expand

public PCollection<T> expand(PBegin input)

Description copied from class: PTransform

Override this method to specify how this PTransform 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).

Specified by:

expand in class PTransform<PBegin,PCollection<T>>

populateDisplayData

public void populateDisplayData(DisplayData.Builder builder)

Description copied from class: PTransform

Register display data for the given transform or component.

populateDisplayData(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.

Specified by:

populateDisplayData in interface HasDisplayData

Overrides:

populateDisplayData in class PTransform<PBegin,PCollection<T>>

Parameters:

builder - The builder to populate with display data.

See Also:

HasDisplayData