Protobuf Jackson

Since Camel 3.10

Jackson Protobuf is a Data Format which uses the Jackson library with the Protobuf extension to unmarshal a Protobuf payload into Java objects or to marshal Java objects into a Protobuf payload.

If you are familiar with Jackson, this Protobuf data format behaves in the same way as its JSON counterpart, and thus can be used with classes annotated for JSON serialization/deserialization.

 
from("kafka:topic").
  unmarshal().protobuf(ProtobufLibrary.Jackson, JsonNode.class).
  to("log:info");

Configuring the SchemaResolver

Since Protobuf serialization is schema-based, this data format requires that you provide a SchemaResolver object that is able to lookup the schema for each exchange that is going to be marshalled/unmarshalled.

You can add a single SchemaResolver to the registry and it will be looked up automatically. Or you can explicitly specify the reference to a custom SchemaResolver.

Protobuf Jackson Options

The Protobuf Jackson dataformat supports 18 options, which are listed below.

Name Default Java Type Description

objectMapper

String

Lookup and use the existing ObjectMapper with the given id when using Jackson.

useDefaultObjectMapper

true

Boolean

Whether to lookup and use default Jackson ObjectMapper from the registry.

autoDiscoverObjectMapper

false

Boolean

If set to true then Jackson will lookup for an objectMapper into the registry.

unmarshalType

String

Class name of the java type to use when unmarshalling.

jsonView

String

When marshalling a POJO to JSON you might want to exclude certain fields from the JSON output. With Jackson you can use JSON views to accomplish this. This option is to refer to the class which has JsonView annotations.

include

String

If you want to marshal a pojo to JSON, and the pojo has some fields with null values. And you want to skip these null values, you can set this option to NON_NULL.

allowJmsType

false

Boolean

Used for JMS users to allow the JMSType header from the JMS spec to specify a FQN classname to use to unmarshal to.

collectionType

String

Refers to a custom collection type to lookup in the registry to use. This option should rarely be used, but allows to use different collection types than java.util.Collection based as default.

useList

false

Boolean

To unmarshal to a List of Map or a List of Pojo.

moduleClassNames

String

To use custom Jackson modules com.fasterxml.jackson.databind.Module specified as a String with FQN class names. Multiple classes can be separated by comma.

moduleRefs

String

To use custom Jackson modules referred from the Camel registry. Multiple modules can be separated by comma.

enableFeatures

String

Set of features to enable on the Jackson com.fasterxml.jackson.databind.ObjectMapper. The features should be a name that matches a enum from com.fasterxml.jackson.databind.SerializationFeature, com.fasterxml.jackson.databind.DeserializationFeature, or com.fasterxml.jackson.databind.MapperFeature Multiple features can be separated by comma.

disableFeatures

String

Set of features to disable on the Jackson com.fasterxml.jackson.databind.ObjectMapper. The features should be a name that matches a enum from com.fasterxml.jackson.databind.SerializationFeature, com.fasterxml.jackson.databind.DeserializationFeature, or com.fasterxml.jackson.databind.MapperFeature Multiple features can be separated by comma.

allowUnmarshallType

false

Boolean

If enabled then Jackson is allowed to attempt to use the CamelJacksonUnmarshalType header during the unmarshalling. This should only be enabled when desired to be used.

timezone

String

If set then Jackson will use the Timezone when marshalling/unmarshalling.

schemaResolver

String

Optional schema resolver used to lookup schemas for the data in transit.

autoDiscoverSchemaResolver

true

Boolean

When not disabled, the SchemaResolver will be looked up into the registry.

contentTypeHeader

true

Boolean

Whether the data format should set the Content-Type header with the type from the data format. For example application/xml for data formats marshalling to XML, or application/json for data formats marshalling to JSON.

Using custom ProtobufMapper

You can configure JacksonProtobufDataFormat to use a custom ProtobufMapper in case you need more control of the mapping configuration.

If you setup a single ProtobufMapper in the registry, then Camel will automatic lookup and use this ProtobufMapper.

Dependencies

To use Protobuf Jackson in your camel routes you need to add the dependency on camel-jackson-protobuf which implements this data format.

If you use maven you could just add the following to your pom.xml, substituting the version number for the latest & greatest release (see the download page for the latest versions).

<dependency>
  <groupId>org.apache.camel</groupId>
  <artifactId>camel-jackson-protobuf</artifactId>
  <version>x.x.x</version>
  <!-- use the same version as your Camel core version -->
</dependency>