Serialization (version 6)

Serialization (version 6)

Version 6 reached End of Life (EOL) and is not actively developed anymore. Upgrading to version 7 is recommended.

While older versions of the driver used mapping features provided by the velocypack library, nowadays it is recommended to use jackson-dataformat-velocypack , which is a VelocyPack dataformat backend for Jackson , supporting the Streaming, Data Binding and Tree Model API styles.

Import in Maven

To add it to your Maven project, add the following to pom.xml:

<dependencies>
    <dependency>
        <groupId>com.arangodb</groupId>
        <artifactId>jackson-dataformat-velocypack</artifactId>
        <version>...</version>
    </dependency>
</dependencies>

The package also depends on jackson-core, jackson-databind and jackson-annotations packages, but when using build tools like Maven or Gradle, dependencies are automatically included. You may however want to use jackson-bom  to ensure dependency convergence across the entire project, for example in case there are in your project other libraries depending on different versions of the same Jackson packages.

<dependencyManagement>
    <dependencies>
        <dependency>
            <groupId>com.fasterxml.jackson</groupId>
            <artifactId>jackson-bom</artifactId>
            <version>...</version>
            <scope>import</scope>
            <type>pom</type>
        </dependency>
    </dependencies>
</dependencyManagement>

jackson-dataformat-velocypack is compatible with Jackson 2.10, 2.11, 2.12, and 2.13.

Configure

Create an instance of ArangoJack, optionally configure the underlying ObjectMapper and pass it to the driver through ArangoDB.Builder.serializer(ArangoSerialization):

ArangoJack arangoJack = new ArangoJack();
arangoJack.configure((mapper) -> {
    // your configuration here
});
ArangoDB arango = new ArangoDB.Builder()
    .serializer(arangoJack)
    // ...
    .build();

where the lambda argument mapper is an instance of VPackMapper, subclass of ObjectMapper. See Jackson Databind  configurable features.

Mapping API

The library is fully compatible with Jackson Databind  API. To customize the serialization and deserialization behavior using the Jackson Data Binding API, entities can be annotated with Jackson Annotations . For more advanced customizations refer to Custom serializer section.

Renaming Properties

To use a different serialized name for a field, use the annotation @JsonProperty.

public class MyObject {

    @JsonProperty("title")
    private String name;

    // ...
}

Ignoring properties

To ignore fields use the annotation @JsonIgnore.

public class Value {
    @JsonIgnore
    public int internalValue;
}

Custom serializer

The serialization and deserialization can be customized using the lower level Streaming API or the Tree Model API, creating and registering respectively JsonSerializer<T> and JsonDeserializer<T>, as specified by the Jackson API for CustomSerializers .

static class PersonSerializer extends JsonSerializer<Person> {
    @Override
    public void serialize(Person value, JsonGenerator gen, SerializerProvider serializers) throws IOException {
        // example using the Streaming API
        gen.writeStartObject();
        gen.writeFieldName("name");
        gen.writeString(value.name);
        gen.writeEndObject();
    }
}

static class PersonDeserializer extends JsonDeserializer<Person> {
    @Override
    public Person deserialize(JsonParser parser, DeserializationContext ctxt) throws IOException {
        // example using the Tree Model API
        Person person = new Person();
        JsonNode rootNode = parser.getCodec().readTree(parser);
        JsonNode nameNode = rootNode.get("name");
        if (nameNode != null && nameNode.isTextual()) {
            person.name = nameNode.asText();
        }
        return person;
    }
}

// registering using annotation
@JsonSerialize(using = PersonSerializer.class)
public static class Person {
    public String name;
}

// ...

// registering programmatically
ArangoJack arangoJack = new ArangoJack();
arangoJack.configure((mapper) -> {
    SimpleModule module = new SimpleModule("PersonModule");
    module.addDeserializer(Person.class, new PersonDeserializer());
    mapper.registerModule(module);
});
ArangoDB arangoDB = new ArangoDB.Builder().serializer(arangoJack).build();

Jackson datatype and language modules

The VPackMapper can be configured with Jackson datatype modules  as well as Jackson JVM Language modules .

Kotlin

Kotlin language module  enables support for Kotlin native types and can be registered in the following way:

val arangoDB = ArangoDB.Builder()
    .serializer(ArangoJack().apply {
        configure { it.registerModule(KotlinModule()) }
    })
    .build()

Scala

Scala language module  enables support for Scala native types and can be registered in the following way:

val arangoJack = new ArangoJack()
arangoJack.configure(mapper => mapper.registerModule(DefaultScalaModule))

val arangoDB = new ArangoDB.Builder()
  .serializer(arangoJack)
  .build()

Java 8 types

Support for Java 8 features is offered by jackson-modules-java8 .

Joda types

Support for Joda data types, such as DateTime, is offered by jackson-datatype-joda .

Metadata fields

To map Arango metadata fields (like _id, _key, _rev, _from, _to) in your entities, use the annotation DocumentField.

public class MyObject {

  @DocumentField(Type.KEY)
  private String key;
  
  // ...
}

Manual serialization

To de-/serialize from and to VelocyPack before or after a database call, use the ArangoUtil from the method util() in ArangoDB, ArangoDatabase, ArangoCollection, ArangoGraph, ArangoEdgeCollectionor ArangoVertexCollection.

ArangoDB arangoDB=new ArangoDB.Builder();
        VPackSlice vpack=arangoDB.util(CUSTOM).serialize(myObj);

ArangoDB arangoDB=new ArangoDB.Builder();
        MyObject myObj=arangoDB.util(CUSTOM).deserialize(vpack,MyObject.class);

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