Package org.acemq.amqp.api

Interface CodecProvider

All Known Implementing Classes:
BuiltInCodecProviders.Bytes, BuiltInCodecProviders.Text, JsonCodecProvider, TomlCodecProvider, XmlCodecProvider, YamlCodecProvider
public interface CodecProvider
Announces a codec to the engine, so that a format can be chosen by name.

Discovered with ServiceLoader, the same way transports are. That is what lets asXml() exist in the core without the core depending on an XML library: the method asks for a codec called xml, and either the module providing it is on the classpath or the error says which artifact to add.

To add a format, implement this and Codec, and name the implementation in META-INF/services/org.acemq.amqp.api.CodecProvider.

  • Method Summary

    Modifier and Type
    Method
    Description
    Codec
    create()
     
    String
    name()
     
    default int
    order()
    Where this codec sits when several could read the same message.

  • Method Details

    • name

      String name()
      Returns:
      the short name this format is asked for by, such as json or xml; lowercase, no spaces

    • create

      Codec create()
      Returns:
      a codec for this format
      Throws:
      AceMqException - if the format's library is missing or misconfigured

    • order

      default int order()
      Where this codec sits when several could read the same message.

      A consumer reads with every codec on the classpath, tried in this order, because a message whose sender set no content type has told us nothing and something usually still reads it. Lower numbers are tried first. Formats that recognise their own bytes belong near the front; a format that accepts anything belongs at the back, or it will answer for messages that were not meant for it.

      Returns:
      the sort key; 500 is a reasonable default for a new format