org.apache.beam.sdk.transforms.join

Class UnionCoder

java.lang.Object

org.apache.beam.sdk.coders.Coder<T>

org.apache.beam.sdk.coders.StructuredCoder<RawUnionValue>

org.apache.beam.sdk.transforms.join.UnionCoder

All Implemented Interfaces:

java.io.Serializable

public class UnionCoder
extends StructuredCoder<RawUnionValue>

A UnionCoder encodes RawUnionValues.

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.beam.sdk.coders.Coder

Coder.Context, Coder.NonDeterministicException

Method Summary

Modifier and Type	Method and Description
RawUnionValue	decode(java.io.InputStream inStream) Decodes a value of type T from the given input stream in the given context.
RawUnionValue	decode(java.io.InputStream inStream, Coder.Context context) Decodes a value of type T from the given input stream in the given context.
void	encode(RawUnionValue union, java.io.OutputStream outStream) Encodes the given value of type T onto the given output stream.
void	encode(RawUnionValue union, java.io.OutputStream outStream, Coder.Context context) Encodes the given value of type T onto the given output stream in the given context.
java.util.List<? extends Coder<?>>	getCoderArguments() 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.
java.util.List<? extends Coder<?>>	getComponents() Returns the list of Coders that are components of this Coder.
java.util.List<? extends Coder<?>>	getElementCoders()
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.
static UnionCoder	of(java.util.List<Coder<?>> elementCoders) Builds a union coder with the given list of element coders.
void	registerByteSizeObserver(RawUnionValue union, org.apache.beam.sdk.util.common.ElementByteSizeObserver observer) Notifies ElementByteSizeObserver about the byte size of the encoded value using this coder.
void	verifyDeterministic() Throw Coder.NonDeterministicException if the coding is not deterministic.

Methods inherited from class org.apache.beam.sdk.coders.StructuredCoder

equals, hashCode, toString

Methods inherited from class org.apache.beam.sdk.coders.Coder

consistentWithEquals, getEncodedElementByteSize, getEncodedTypeDescriptor, structuralValue, verifyDeterministic, verifyDeterministic

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Method Detail

of

public static UnionCoder of(java.util.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,
                   java.io.OutputStream outStream)
            throws java.io.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:

java.io.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,
                   java.io.OutputStream outStream,
                   Coder.Context context)
            throws java.io.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:

java.io.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(java.io.InputStream inStream)
                     throws java.io.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:

java.io.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(java.io.InputStream inStream,
                            Coder.Context context)
                     throws java.io.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:

java.io.IOException - if reading from the InputStream fails for some reason

CoderException - if the value could not be decoded for some reason

getCoderArguments

public java.util.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 java.util.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 java.util.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 java.lang.Exception

Notifies ElementByteSizeObserver about the byte size of the encoded value using this coder.

Overrides:

registerByteSizeObserver in class Coder<RawUnionValue>

Throws:

java.lang.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.