Package cz.o2.proxima.beam.core.transforms

Class BufferUntilCheckpoint<T>

  • Type Parameters:
    T - Element type
    All Implemented Interfaces:
    java.io.Serializable, org.apache.beam.sdk.transforms.display.HasDisplayData
    public class BufferUntilCheckpoint<T>
extends org.apache.beam.sdk.transforms.DoFn<T,​T>
    Identity transformation which ensures exactly-once output. Generally an input elements are buffered and are outputs only when checkpoint is stored successfully.

    Use this transformation when output is not stable (e.g. random values) or when transformation generates side effects which are not idempotent. For details @see Beam design document

    See Also:
    Serialized Form

    • Nested Class Summary

      • Nested classes/interfaces inherited from class org.apache.beam.sdk.transforms.DoFn

        org.apache.beam.sdk.transforms.DoFn.AlwaysFetched, org.apache.beam.sdk.transforms.DoFn.BoundedPerElement, org.apache.beam.sdk.transforms.DoFn.BundleFinalizer, org.apache.beam.sdk.transforms.DoFn.Element, org.apache.beam.sdk.transforms.DoFn.FieldAccess, org.apache.beam.sdk.transforms.DoFn.FinishBundle, org.apache.beam.sdk.transforms.DoFn.FinishBundleContext, org.apache.beam.sdk.transforms.DoFn.GetInitialRestriction, org.apache.beam.sdk.transforms.DoFn.GetInitialWatermarkEstimatorState, org.apache.beam.sdk.transforms.DoFn.GetRestrictionCoder, org.apache.beam.sdk.transforms.DoFn.GetSize, org.apache.beam.sdk.transforms.DoFn.GetWatermarkEstimatorStateCoder, org.apache.beam.sdk.transforms.DoFn.Key, org.apache.beam.sdk.transforms.DoFn.MultiOutputReceiver, org.apache.beam.sdk.transforms.DoFn.NewTracker, org.apache.beam.sdk.transforms.DoFn.NewWatermarkEstimator, org.apache.beam.sdk.transforms.DoFn.OnTimer, org.apache.beam.sdk.transforms.DoFn.OnTimerContext, org.apache.beam.sdk.transforms.DoFn.OnTimerFamily, org.apache.beam.sdk.transforms.DoFn.OnWindowExpiration, org.apache.beam.sdk.transforms.DoFn.OnWindowExpirationContext, org.apache.beam.sdk.transforms.DoFn.OutputReceiver<T extends java.lang.Object>, org.apache.beam.sdk.transforms.DoFn.ProcessContext, org.apache.beam.sdk.transforms.DoFn.ProcessContinuation, org.apache.beam.sdk.transforms.DoFn.ProcessElement, org.apache.beam.sdk.transforms.DoFn.RequiresStableInput, org.apache.beam.sdk.transforms.DoFn.RequiresTimeSortedInput, org.apache.beam.sdk.transforms.DoFn.Restriction, org.apache.beam.sdk.transforms.DoFn.Setup, org.apache.beam.sdk.transforms.DoFn.SideInput, org.apache.beam.sdk.transforms.DoFn.SplitRestriction, org.apache.beam.sdk.transforms.DoFn.StartBundle, org.apache.beam.sdk.transforms.DoFn.StartBundleContext, org.apache.beam.sdk.transforms.DoFn.StateId, org.apache.beam.sdk.transforms.DoFn.Teardown, org.apache.beam.sdk.transforms.DoFn.TimerFamily, org.apache.beam.sdk.transforms.DoFn.TimerId, org.apache.beam.sdk.transforms.DoFn.Timestamp, org.apache.beam.sdk.transforms.DoFn.TruncateRestriction, org.apache.beam.sdk.transforms.DoFn.UnboundedPerElement, org.apache.beam.sdk.transforms.DoFn.WatermarkEstimatorState, org.apache.beam.sdk.transforms.DoFn.WindowedContext

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      void processElement​(T input, org.apache.beam.sdk.transforms.DoFn.OutputReceiver<T> out)  

      • Methods inherited from class org.apache.beam.sdk.transforms.DoFn

        getAllowedTimestampSkew, getInputTypeDescriptor, getOutputTypeDescriptor, populateDisplayData, prepareForProcessing

      • Methods inherited from class java.lang.Object

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

    • Constructor Detail

      • BufferUntilCheckpoint

        public BufferUntilCheckpoint()

    • Method Detail

      • processElement

        @RequiresStableInput
@ProcessElement
public void processElement​(@Element
                           T input,
                           org.apache.beam.sdk.transforms.DoFn.OutputReceiver<T> out)