| Class | Description | 
|---|---|
| ConsoleIO | Print to console. | 
| ConsoleIO.Write | Write to console. | 
| ConsoleIO.Write.Unbound<T> | PTransformwritingPCollectionto the console. | 
| CreateStream<T> | Create an input stream from Queue. | 
| EmptyCheckpointMark | Passing null values to Spark's Java API may cause problems because of Guava preconditions. | 
| MicrobatchSource<T,CheckpointMarkT extends UnboundedSource.CheckpointMark> | A  Sourcethat accommodates Spark's micro-batch oriented nature and wraps anUnboundedSource. | 
| SourceRDD | Classes implementing Beam  SourceRDDs. | 
| SourceRDD.Bounded<T> | |
| SourceRDD.Unbounded<T,CheckpointMarkT extends UnboundedSource.CheckpointMark> | A  SourceRDD.Unboundedis the implementation of a micro-batch in aSourceDStream. | 
| SparkUnboundedSource | A "composite" InputDStream implementation for  UnboundedSources. | 
| SparkUnboundedSource.Metadata | A metadata holder for an input stream partition. |