Package org.apache.beam.sdk.transforms

Class LogElements<T>

java.lang.Object
org.apache.beam.sdk.transforms.PTransform<PCollection<T>,PCollection<T>>
org.apache.beam.sdk.transforms.LogElements<T>
Type Parameters:
T - the element type of the input PCollection
All Implemented Interfaces:
Serializable, HasDisplayData
public class LogElements<T> extends PTransform<PCollection<T>,PCollection<T>>
PTransform for logging elements of a PCollection.

Each element is logged and then emitted unchanged. 


 PCollection<String> words = ...;
 PCollection<String> loggedWords = words.apply(LogElements.info().withPrefix("word: "));
See Also:

  • Method Details

    • trace

      public static <T> LogElements<T> trace()
      Returns a LogElements transform that logs elements at Level.TRACE.

    • debug

      public static <T> LogElements<T> debug()
      Returns a LogElements transform that logs elements at Level.DEBUG.

    • info

      public static <T> LogElements<T> info()
      Returns a LogElements transform that logs elements at Level.INFO.

    • warn

      public static <T> LogElements<T> warn()
      Returns a LogElements transform that logs elements at Level.WARN.

    • error

      public static <T> LogElements<T> error()
      Returns a LogElements transform that logs elements at Level.ERROR.

    • of

      public static <T> LogElements<T> of(Level level)
      Returns a LogElements transform that logs elements at the given level.

    • withPrefix

      public LogElements<T> withPrefix(String prefix)
      Returns a new LogElements transform with the given prefix before each element.

    • withTimestamp

      public LogElements<T> withTimestamp()
      Returns a new LogElements transform that logs each element's timestamp.

    • withWindow

      public LogElements<T> withWindow()
      Returns a new LogElements transform that logs each element's window.

    • withPaneInfo

      public LogElements<T> withPaneInfo()
      Returns a new LogElements transform that logs each element's pane info.

    • expand

      public PCollection<T> expand(PCollection<T> 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<PCollection<T>,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<PCollection<T>,PCollection<T>>
      Parameters:
      builder - The builder to populate with display data.
      See Also: