Package org.apache.beam.sdk.transforms.join

Class UnionCoder

java.lang.Object
org.apache.beam.sdk.coders.Coder<RawUnionValue>
org.apache.beam.sdk.coders.StructuredCoder<RawUnionValue>
org.apache.beam.sdk.transforms.join.UnionCoder
All Implemented Interfaces:
Serializable
public class UnionCoder extends StructuredCoder<RawUnionValue>
A UnionCoder encodes RawUnionValues.
See Also:

  • Method Details

    • of

      public static UnionCoder of(List<Coder<?>> elementCoders)
      Builds a union coder with the given list of element coders. This list corresponds to a mapping of union tag to Coder. Union tags start at 0.

    • encode

      public void encode(RawUnionValue union, OutputStream outStream) throws IOException, CoderException
      Description copied from class: Coder
      Encodes the given value of type T onto the given output stream. Multiple elements can be encoded next to each other on the output stream, each coder should encode information to know how many bytes to read when decoding. A common approach is to prefix the encoding with the element's encoded length.
      Specified by:
      encode in class Coder<RawUnionValue>
      Throws:
      IOException - if writing to the OutputStream fails for some reason
      CoderException - if the value could not be encoded for some reason

    • encode

      public void encode(RawUnionValue union, OutputStream outStream, Coder.Context context) throws IOException, CoderException
      Description copied from class: Coder
      Encodes the given value of type T onto the given output stream in the given context.
      Overrides:
      encode in class Coder<RawUnionValue>
      Throws:
      IOException - if writing to the OutputStream fails for some reason
      CoderException - if the value could not be encoded for some reason

    • decode

      public RawUnionValue decode(InputStream inStream) throws IOException, CoderException
      Description copied from class: Coder
      Decodes a value of type T from the given input stream in the given context. Returns the decoded value. Multiple elements can be encoded next to each other on the input stream, each coder should encode information to know how many bytes to read when decoding. A common approach is to prefix the encoding with the element's encoded length.
      Specified by:
      decode in class Coder<RawUnionValue>
      Throws:
      IOException - if reading from the InputStream fails for some reason
      CoderException - if the value could not be decoded for some reason

    • decode

      public RawUnionValue decode(InputStream inStream, Coder.Context context) throws IOException, CoderException
      Description copied from class: Coder
      Decodes a value of type T from the given input stream in the given context. Returns the decoded value.
      Overrides:
      decode in class Coder<RawUnionValue>
      Throws:
      IOException - if reading from the InputStream fails for some reason
      CoderException - if the value could not be decoded for some reason

    • getCoderArguments

      public List<? extends Coder<?>> getCoderArguments()
      Description copied from class: Coder
      If this is a Coder for a parameterized type, returns the list of Coders being used for each of the parameters in the same order they appear within the parameterized type's type signature. If this cannot be done, or this Coder does not encode/decode a parameterized type, returns the empty list.
      Specified by:
      getCoderArguments in class Coder<RawUnionValue>

    • getComponents

      public List<? extends Coder<?>> getComponents()
      Description copied from class: StructuredCoder
      Returns the list of Coders that are components of this Coder.

      The default components will be equal to the value returned by Coder.getCoderArguments().

      Overrides:
      getComponents in class StructuredCoder<RawUnionValue>

    • getElementCoders

      public List<? extends Coder<?>> getElementCoders()

    • isRegisterByteSizeObserverCheap

      public boolean isRegisterByteSizeObserverCheap(RawUnionValue union)
      Since this coder uses elementCoders.get(index) and coders that are known to run in constant time, we defer the return value to that coder.
      Overrides:
      isRegisterByteSizeObserverCheap in class Coder<RawUnionValue>

    • registerByteSizeObserver

      public void registerByteSizeObserver(RawUnionValue union, org.apache.beam.sdk.util.common.ElementByteSizeObserver observer) throws Exception
      Notifies ElementByteSizeObserver about the byte size of the encoded value using this coder.
      Overrides:
      registerByteSizeObserver in class Coder<RawUnionValue>
      Throws:
      Exception

    • verifyDeterministic

      public void verifyDeterministic() throws Coder.NonDeterministicException
      Description copied from class: Coder
      Throw Coder.NonDeterministicException if the coding is not deterministic.

      In order for a Coder to be considered deterministic, the following must be true:

      • two values that compare as equal (via Object.equals() or Comparable.compareTo(), if supported) have the same encoding.
      • the Coder always produces a canonical encoding, which is the same for an instance of an object even if produced on different computers at different times.
      Specified by:
      verifyDeterministic in class Coder<RawUnionValue>
      Throws:
      Coder.NonDeterministicException - if this coder is not deterministic.