Package org.apache.beam.sdk.coders

Class ByteArrayCoder

java.lang.Object
org.apache.beam.sdk.coders.Coder<byte[]>
org.apache.beam.sdk.coders.StructuredCoder<byte[]>
org.apache.beam.sdk.coders.AtomicCoder<byte[]>
org.apache.beam.sdk.coders.ByteArrayCoder
All Implemented Interfaces:
Serializable
public class ByteArrayCoder extends AtomicCoder<byte[]>
A Coder for byte[].

The encoding format is as follows:

  • If in a non-nested context (the byte[] is the only value in the stream), the bytes are read/written directly.
  • If in a nested context, the bytes are prefixed with the length of the array, encoded via a VarIntCoder.
See Also:

  • Method Details

    • of

      public static ByteArrayCoder of()

    • encode

      public void encode(byte[] value, 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<byte[]>
      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(byte[] value, 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<byte[]>
      Throws:
      IOException - if writing to the OutputStream fails for some reason
      CoderException - if the value could not be encoded for some reason

    • encodeAndOwn

      public void encodeAndOwn(byte[] value, OutputStream outStream, Coder.Context context) throws IOException, CoderException
      Encodes the provided value with the identical encoding to encode(byte[], java.io.OutputStream), but with optimizations that take ownership of the value.

      Once passed to this method, value should never be observed or mutated again.

      Throws:
      IOException
      CoderException

    • decode

      public byte[] 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<byte[]>
      Throws:
      IOException - if reading from the InputStream fails for some reason
      CoderException - if the value could not be decoded for some reason

    • decode

      public byte[] 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<byte[]>
      Throws:
      IOException - if reading from the InputStream fails for some reason
      CoderException - if the value could not be decoded for some reason

    • verifyDeterministic

      public void verifyDeterministic()
      Description copied from class: AtomicCoder
      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.
      .

      Unless overridden, does not throw. An AtomicCoder is presumed to be deterministic

      Overrides:
      verifyDeterministic in class AtomicCoder<byte[]>

    • structuralValue

      public Object structuralValue(byte[] value)
      Returns an object with an Object.equals() method that represents structural equality on the argument.

      For any two values x and y of type T, if their encoded bytes are the same, then it must be the case that structuralValue(x).equals(structuralValue(y)).

      Most notably:

      • The structural value for an array coder should perform a structural comparison of the contents of the arrays, rather than the default behavior of comparing according to object identity.
      • The structural value for a coder accepting null should be a proper object with an equals() method, even if the input value is null.

      See also Coder.consistentWithEquals().

      By default, if this coder is Coder.consistentWithEquals(), and the value is not null, returns the provided object. Otherwise, encodes the value into a byte[], and returns an object that performs array equality on the encoded bytes.

      Overrides:
      structuralValue in class Coder<byte[]>
      Returns:
      objects that are equal if the two arrays contain the same bytes.

    • isRegisterByteSizeObserverCheap

      public boolean isRegisterByteSizeObserverCheap(byte[] value)
      Returns whether Coder.registerByteSizeObserver(T, org.apache.beam.sdk.util.common.ElementByteSizeObserver) cheap enough to call for every element, that is, if this Coder can calculate the byte size of the element to be coded in roughly constant time (or lazily).

      Not intended to be called by user code, but instead by PipelineRunner implementations.

      By default, returns false. The default Coder.registerByteSizeObserver(T, org.apache.beam.sdk.util.common.ElementByteSizeObserver) implementation invokes Coder.getEncodedElementByteSize(T) which requires re-encoding an element unless it is overridden. This is considered expensive.

      Overrides:
      isRegisterByteSizeObserverCheap in class Coder<byte[]>
      Returns:
      true since getEncodedElementByteSize(byte[]) runs in constant time using the length of the provided array.

    • getEncodedTypeDescriptor

      public TypeDescriptor<byte[]> getEncodedTypeDescriptor()
      Description copied from class: Coder
      Returns the TypeDescriptor for the type encoded.
      Overrides:
      getEncodedTypeDescriptor in class Coder<byte[]>

    • getEncodedElementByteSize

      protected long getEncodedElementByteSize(byte[] value) throws Exception
      Description copied from class: Coder
      Returns the size in bytes of the encoded value using this coder.
      Overrides:
      getEncodedElementByteSize in class Coder<byte[]>
      Throws:
      Exception