[FEATURE] Provide an easy way to deserialize classes annotated as @JsonpDeserializable

[campidelli-wcq]

Is your feature request related to a problem?

We are migrating from Elasticsearch to Opensearch and we have some JSON files that are used to create index templates. That is how we used to do it:

    public void putIndexTemplate(final String pTemplateName, final InputStream pTemplateJson) throws IOException {
        PutIndexTemplateRequest putIndexTemplateRequest = new PutIndexTemplateRequest.Builder()
            .name(pTemplateName)
            .withJson(pTemplateJson)
            .build();
       PutIndexTemplateResponse putIndexTemplateResponse = client.indices().putIndexTemplate(putIndexTemplateRequest);
        log.info(putIndexTemplateResponse.toString());
    }

But that .withJson method is no longer available.

What solution would you like?

We could have the .withJson method added to the Builder, since the request class already has a JsonpDeserializer<PutIndexTemplateRequest> _DESERIALIZER. Or another alternative that would allow us to keep using the builder.

What alternatives have you considered?

First I have tried to use the built-in deserializer, like this:

public void putIndexTemplate(final String pTemplateName, final InputStream pTemplateJson) throws IOException {
        JsonpMapper mapper = client._transport().jsonpMapper();
        JsonParser parser = mapper.jsonProvider().createParser(pTemplateJson);

        PutIndexTemplateRequest request = PutIndexTemplateRequest._DESERIALIZER.deserialize(parser, mapper);
        // request is immutable, I can't set request.setName(pTemplateName)
        PutIndexTemplateResponse response = client.indices().putIndexTemplate(request);

        log.info(response.toString());
}

Then I had to build my own Deserializer to return a Builder instead:

public final class PutIndexTemplateRequestBuilderDeserializer {
    private static final ObjectDeserializer<PutIndexTemplateRequest.Builder> od = new ObjectDeserializer<>(PutIndexTemplateRequest.Builder::new);

    static {
        od.add(PutIndexTemplateRequest.Builder::meta, stringMapDeserializer(JsonData._DESERIALIZER), "_meta");
        od.add(PutIndexTemplateRequest.Builder::composedOf, arrayDeserializer(stringDeserializer()), "composed_of");
        od.add(PutIndexTemplateRequest.Builder::dataStream, DataStream._DESERIALIZER, "data_stream");
        od.add(PutIndexTemplateRequest.Builder::indexPatterns, arrayDeserializer(stringDeserializer()), "index_patterns");
        od.add(PutIndexTemplateRequest.Builder::priority, JsonpDeserializer.integerDeserializer(), "priority");
        od.add(PutIndexTemplateRequest.Builder::template, IndexTemplateMapping._DESERIALIZER, "template");
        od.add(PutIndexTemplateRequest.Builder::version, JsonpDeserializer.longDeserializer(), "version");
    }

    public static PutIndexTemplateRequest.Builder deserialize(JsonpMapper mapper, JsonParser parser) {
        return od.deserialize(parser, mapper);
    }
}

And finally use it in my class:

    public void putIndexTemplate(final String pTemplateName, final InputStream pTemplateJson) throws IOException {
        JsonpMapper mapper = client._transport().jsonpMapper();
        JsonParser parser = mapper.jsonProvider().createParser(pTemplateJson);

        PutIndexTemplateRequest request = PutIndexTemplateRequestBuilderDeserializer
            .deserialize(mapper, parser)
            .name(pTemplateName)
            .build();
        PutIndexTemplateResponse response = client.indices().putIndexTemplate(request);

        log.info(response.toString());
    }

Do you have any additional context?

One last thing, there is no documentation whatsoever describing how to do this, and I think it is not a very unusual scenario.

Thanks for considering it.

[dblock]

I think this is a dup with #257, would love for someone to contribute this feature!

[pranishd1]

Hi, I would like to work in this issue.

[VachaShah]

All yours @pranishd1, thank you!