com.google.cloud.dataflow.sdk.coders

Class Proto2Coder<T extends com.google.protobuf.Message>

java.lang.Object

com.google.cloud.dataflow.sdk.coders.StandardCoder<T>

com.google.cloud.dataflow.sdk.coders.AtomicCoder<T>

com.google.cloud.dataflow.sdk.coders.CustomCoder<T>

com.google.cloud.dataflow.sdk.coders.Proto2Coder<T>

Type Parameters:

T - the type of elements handled by this coder, must extend Message

All Implemented Interfaces:

Coder<T>, java.io.Serializable

public class Proto2Coder<T extends com.google.protobuf.Message>
extends CustomCoder<T>

An encoder using Google Protocol Buffers 2 binary format.

To learn more about Protocol Buffers, visit: https://developers.google.com/protocol-buffers

To use, specify the Coder type on a PCollection:

 PCollection<MyProto.Message> records =
     input.apply(...)
          .setCoder(Proto2Coder.of(MyProto.Message.class));
 
 

Custom message extensions are also supported, but the coder must be made aware of them explicitly:

 PCollection<MyProto.Message> records =
     input.apply(...)
          .setCoder(Proto2Coder.of(MyProto.Message.class)
          .withExtensionsFrom(MyProto.class));
 
 

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from interface com.google.cloud.dataflow.sdk.coders.Coder

Coder.Context, Coder.NonDeterministicException

Method Summary

Methods

Modifier and Type	Method and Description
T	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(T value, java.io.OutputStream outStream, Coder.Context context) Encodes the given value of type T onto the given output stream in the given context.
static <T extends com.google.protobuf.Message> Proto2Coder<T>	of(java.lang.Class<T> protoMessageClass) Produces a new Proto2Coder instance, for a given Protobuf message class.
Proto2Coder<T>	withExtensionsFrom(java.lang.Class<?>... extensionHosts) Adds custom Protobuf extensions to the coder.

Methods inherited from class com.google.cloud.dataflow.sdk.coders.CustomCoder

asCloudObject, isDeterministic, of

Methods inherited from class com.google.cloud.dataflow.sdk.coders.AtomicCoder

getCoderArguments, getInstanceComponents

Methods inherited from class com.google.cloud.dataflow.sdk.coders.StandardCoder

equals, getComponents, getEncodedElementByteSize, hashCode, isRegisterByteSizeObserverCheap, registerByteSizeObserver, toString, verifyDeterministic, verifyDeterministic, verifyDeterministic

Methods inherited from class java.lang.Object

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

Method Detail

of

public static <T extends com.google.protobuf.Message> Proto2Coder<T> of(java.lang.Class<T> protoMessageClass)

Produces a new Proto2Coder instance, for a given Protobuf message class.

withExtensionsFrom

public Proto2Coder<T> withExtensionsFrom(java.lang.Class<?>... extensionHosts)

Adds custom Protobuf extensions to the coder.

Parameters:

extensionHosts - must be a class that defines a static method name registerAllExtensions

encode

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

Description copied from interface: Coder

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

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

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

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