org.apache.beam.sdk.coders

Class JAXBCoder<T>

java.lang.Object

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

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

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

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

Type Parameters:

T - type of JAXB annotated objects that will be serialized.

All Implemented Interfaces:

Serializable, Coder<T>

public class JAXBCoder<T>
extends AtomicCoder<T>

A coder for JAXB annotated objects. This coder uses JAXB marshalling/unmarshalling mechanisms to encode/decode the objects. Users must provide the Class of the JAXB annotated object.

See Also:

Serialized Form

Nested Class Summary

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

Coder.Context, Coder.NonDeterministicException

Method Summary

Modifier and Type	Method and Description
org.apache.beam.sdk.util.CloudObject	asCloudObject() Returns the CloudObject that represents this Coder.
T	decode(InputStream inStream, Coder.Context context) Decodes a value of type T from the given input stream in the given context.
void	encode(T value, OutputStream outStream, Coder.Context context) Encodes the given value of type T onto the given output stream in the given context.
String	getEncodingId() An identifier for the binary format written by Coder.encode(T, java.io.OutputStream, org.apache.beam.sdk.coders.Coder.Context).
Class<T>	getJAXBClass()
static <T> JAXBCoder<T>	of(Class<T> jaxbClass) Create a coder for a given type of JAXB annotated objects.
static <T> JAXBCoder<T>	of(String jaxbClassName) Constructor for JSON deserialization only.

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

getCoderArguments, getInstanceComponents

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

verifyDeterministic

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

consistentWithEquals, equals, getAllowedEncodings, getComponents, getEncodedElementByteSize, hashCode, isRegisterByteSizeObserverCheap, registerByteSizeObserver, structuralValue, toString, verifyDeterministic, verifyDeterministic

Methods inherited from class java.lang.Object

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

Method Detail

getJAXBClass

public Class<T> getJAXBClass()

of

public static <T> JAXBCoder<T> of(Class<T> jaxbClass)

Create a coder for a given type of JAXB annotated objects.

Parameters:

jaxbClass - the Class of the JAXB annotated objects.

encode

public void encode(T value,
                   OutputStream outStream,
                   Coder.Context context)
            throws CoderException,
                   IOException

Description copied from interface: Coder

Encodes the given value of type T onto the given output stream in the given context.

Throws:

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

IOException - if writing to the OutputStream fails for some reason

decode

public T decode(InputStream inStream,
                Coder.Context context)
         throws CoderException,
                IOException

Description copied from interface: Coder

Decodes a value of type T from the given input stream in the given context. Returns the decoded value.

Throws:

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

IOException - if reading from the InputStream fails for some reason

getEncodingId

public String getEncodingId()

Description copied from interface: Coder

An identifier for the binary format written by Coder.encode(T, java.io.OutputStream, org.apache.beam.sdk.coders.Coder.Context).

This value, along with the fully qualified class name, forms an identifier for the binary format of this coder. Whenever this value changes, the new encoding is considered incompatible with the prior format: It is presumed that the prior version of the coder will be unable to correctly read the new format and the new version of the coder will be unable to correctly read the old format.

If the format is changed in a backwards-compatible way (the Coder can still accept data from the prior format), such as by adding optional fields to a Protocol Buffer or Avro definition, and you want Dataflow to understand that the new coder is compatible with the prior coder, this value must remain unchanged. It is then the responsibility of Coder.decode(java.io.InputStream, org.apache.beam.sdk.coders.Coder.Context) to correctly read data from the prior format.

Specified by:

getEncodingId in interface Coder<T>

Overrides:

getEncodingId in class StandardCoder<T>

of

public static <T> JAXBCoder<T> of(String jaxbClassName)

Constructor for JSON deserialization only.

asCloudObject

public org.apache.beam.sdk.util.CloudObject asCloudObject()

Description copied from interface: Coder

Returns the CloudObject that represents this Coder.

Specified by:

asCloudObject in interface Coder<T>

Overrides:

asCloudObject in class StandardCoder<T>