How to start using Messagepack in my below code?

[Raihan Jamal]

I am planning to use `Messagepack` in our project. Currently, we are using `JSON` in our project and we are writing serialize JSON document into Cassandra. Now we are thinking to use `Messagepack` which is an efficient binary serialization format.

And I believe using MessagePack in our project is almost a drop-in optimization. Below is my code which is serializing the JSON document using ObjectMapper.

public static void main(String[] args) throws IOException {

final long lmd = System.currentTimeMillis();

Map<String, Object> props = new HashMap<String, Object>();

props.put("site-id", 0);

props.put("price-score", 0.5);

props.put("confidence-score", 0.2);

Map<String, Category> categories = new HashMap<String, Category>();

categories.put("123", new Category("0.4", "0.2"));

categories.put("321", new Category("0.2", "0.5"));

props.put("categories", categories);

AttributeValue av = new AttributeValue(); // using Jackson in this class

av.setProperties(props);

Attribute attr = new Attribute(); // using jackson in this class

attr.instantiateNewListValue();

attr.getListValue().add(av);

attr.setLastModifiedDate(lmd);

System.out.println(attr); 

// serialize it

try {

String jsonStr = new ObjectMapper().writeValueAsString(attr);

// write into database

System.out.println(jsonStr);

} catch (JsonGenerationException e) {

e.printStackTrace();

} catch (JsonMappingException e) {

e.printStackTrace();

} catch (IOException e) {

e.printStackTrace();

}

}

Both of my classes, AttributeValue and Attribute are using Jackson annotations and making a JSON document for me.

Now I am not sure, how to use Messagepack in my above code as I am not able to find clear documentation on it. Can anyone help me with that?

[Mitsunori Komatsu]

Hi Raihan,

How about like this?

@Message

public static class Category {

    String fst;

    String snd;

    public Category() {} // needed by MessagePack(internally Javassist)

    public Category(String fst, String snd) {

        this.fst = fst;

        this.snd = snd;

    }

}

public static void main(String[] args) throws IOException, URISyntaxException, InterruptedException, ExecutionException {

    Map<String, Object> props = new HashMap<String, Object>();

    props.put("site-id", 0);

    props.put("price-score", 0.5);

    props.put("confidence-score", 0.2);

    Map<String, Category> categories = new HashMap<String, Category>();

    categories.put("123", new Category("0.4", "0.2"));

    categories.put("321", new Category("0.2", "0.5"));

    props.put("categories", categories);

    MessagePack msgpack = new JSON();

    BufferPacker packer = msgpack.createBufferPacker();

    packer.write(props);

    byte[] ser = packer.toByteArray();

    // write into database

    System.out.println(new String(ser));

}

Thanks,

Mitsunori