Cannot provide coder

[Antony Mayi <an...@yahoo.com>]

Hi,
trying to create PCollection of my custom data class but keep failing due to the CannotProvideCoderException:
My class is declared as follows:
@DefaultCoder(SerializableCoder.class) public class Data<DataT extends BaseData> implements Serializable {
and it fails like this:
Caused by: org.apache.beam.sdk.coders.CannotProvideCoderException: Cannot provide coder based on value with class my.project.Data: No CoderFactory has been registered for the class.
why it doesn't pick the coder?
thanks,Antony.

Re: Cannot provide coder

[Kenneth Knowles <kl...@google.com>]

Hi Antony,

Thanks for the report!

You are right about the easiest way to fix this: use Create.withCoder(...).
It is generally the best practice as Create actually infers coders in a way
that is different from everywhere else (we would like this to be invisible,
but unfortunately we cannot quite make it so).

But I also think that (1) your example should work and use
SerializableCoder and (2) the error message you saw is not good enough. So
I have filed https://issues.apache.org/jira/browse/BEAM-1736

Kenn

On Mon, Mar 13, 2017 at 8:28 AM, Antony Mayi <an...@yahoo.com> wrote:

> to answer myself:
>
> I should have said I am creating the PCollection<Data> using Create.of
> which apparently leads to this getDefaultCoder() implementation:
> CoderRegistry.getDefaultCoder(T exampleValue)
> <https://github.com/apache/beam/blob/master/sdks/java/core/src/main/java/org/apache/beam/sdk/coders/CoderRegistry.java#L257> which
> doesn't try inspecting the annotation (as opposed
> CoderRegistry.getDefaultCoder(Class<T> clazz)
> <https://github.com/apache/beam/blob/release-0.5.0/sdks/java/core/src/main/java/org/apache/beam/sdk/coders/CoderRegistry.java#L313> ).
> So I guess I have to explicitly use the create.of().withCoder().
>
> antony.
>
>
> On Monday, 13 March 2017, 13:37, Antony Mayi <an...@yahoo.com> wrote:
>
>
> Hi,
>
> trying to create PCollection of my custom data class but keep failing due
> to the CannotProvideCoderException:
>
> My class is declared as follows:
>
> @DefaultCoder(SerializableCoder.class) public class Data<DataT extends
> BaseData> implements Serializable {
>
> and it fails like this:
>
> Caused by: org.apache.beam.sdk.coders.CannotProvideCoderException: Cannot
> provide coder based on value with class my.project.Data: No CoderFactory
> has been registered for the class.
>
> why it doesn't pick the coder?
>
> thanks,
> Antony.
>
>
>

Re: Cannot provide coder

[Antony Mayi <an...@yahoo.com>]

to answer myself:
I should have said I am creating the PCollection<Data> using Create.of which apparently leads to this getDefaultCoder() implementation: CoderRegistry.getDefaultCoder(T exampleValue) which doesn't try inspecting the annotation (as opposed CoderRegistry.getDefaultCoder(Class<T> clazz) ). So I guess I have to explicitly use the create.of().withCoder().
antony. 

    On Monday, 13 March 2017, 13:37, Antony Mayi <an...@yahoo.com> wrote:
 

 Hi,
trying to create PCollection of my custom data class but keep failing due to the CannotProvideCoderException:
My class is declared as follows:
@DefaultCoder(SerializableCoder.class) public class Data<DataT extends BaseData> implements Serializable {
and it fails like this:
Caused by: org.apache.beam.sdk.coders.CannotProvideCoderException: Cannot provide coder based on value with class my.project.Data: No CoderFactory has been registered for the class.
why it doesn't pick the coder?
thanks,Antony.