Java implementation for VelocyPack.
To add the dependency to your project with maven, add the following code to your pom.xml:
<dependencies> <dependency> <groupId>com.arangodb</groupId> <artifactId>velocypack</artifactId> <version>x.y.z</version> </dependency> </dependencies>mvn clean install -DskipTests=true -Dgpg.skip=true -Dmaven.javadoc.skip=true -B VPackBuilder builder = new VPackBuilder(); builder.add(ValueType.OBJECT); // object start builder.add("foo", "bar"); // add field "foo" with value "bar" builder.close(); // object end VPackSlice slice = builder.slice(); // create slice VPackSlice slice = ... int size = slice.size(); // number of fields VPackSlice foo = slice.get("foo"); // get field "foo" String value = foo.getAsString(); // get value from "foo" // iterate over the fields for (final Iterator<Entry<String, VPackSlice>> iterator = slice.objectIterator(); iterator.hasNext();) { Entry<String, VPackSlice> field = iterator.next(); ... } VPackBuilder builder = new VPackBuilder(); builder.add(ValueType.ARRAY); // array start builder.add(1); // add value 1 builder.add(2); // add value 2 builder.add(3); // add value 3 builder.close(); // array end VPackSlice slice = builder.slice(); // create slice VPackSlice slice = ... int size = slice.size(); // number of values // iterate over values for (int i = 0; i < slice.size(); i++) { VPackSlice value = slice.get(i); ... } // iterate over values with Iterator for (final Iterator<VPackSlice> iterator = slice.arrayIterator(); iterator.hasNext();) { VPackSlice value = iterator.next(); ... } VPackBuilder builder = new VPackBuilder(); builder.add(ValueType.OBJECT); // object start builder.add("foo", ValueType.OBJECT); // add object in field "foo" builder.add("bar", 1); // add field "bar" with value 1 to object "foo" builder.close(); // object "foo" end builder.close(); // object end VPackSlice slice = builder.slice(); // create slice MyBean entity = new MyBean(); VPack vpack = new VPack.Builder().build(); VPackSlice slice = vpack.serialize(entity); VPackSlice slice = ... VPack vpack = new VPack.Builder().build(); MyBean entity = vpack.deserialize(slice, MyBean.class); String json = ... VPackParser parser = new VPackParser.Builder().build(); VPackSlice slice = parser.fromJson(json); VPackSlice slice = ... VPackParser parser = new VPackParser.Builder().build(); String json = parser.toJson(slice);Both VPack and VPackParser allow registering of modules which can offer custom serializers/deserializers for additional types.
VPackModule module = ... VPack vpack = new VPack.Builder().registerModule(module).build(); VPackParserModule module = ... VPackParser parser = VPackParser.Builder().registerModule(module).build();The class VPack can serialize/deserialize POJOs. They need at least a constructor without parameter. Also Builder deserialization, All-Arguments-Constructor deserialization and Static Factory Method deserialization are supported.
public class MyObject { private String name; private Gender gender; private int age; public MyObject() { super(); } }To use a different serialized name for a field, use the annotation SerializedName.
public class MyObject { @SerializedName("title") private String name; private Gender gender; private int age; public MyObject() { super(); } }To ignore fields at serialization/deserialization, use the annotation Expose
public class MyObject { @Expose private String name; @Expose(serialize = true, deserialize = false) private Gender gender; private int age; public MyObject() { super(); } } VPack vpack = new VPack.Builder() .registerDeserializer(MyObject.class, new VPackDeserializer<MyObject>() { @Override public MyObject deserialize( final VPackSlice parent, final VPackSlice vpack, final VPackDeserializationContext context) throws VPackException { final MyObject obj = new MyObject(); obj.setName(vpack.get("name").getAsString()); return obj; } }).registerSerializer(MyObject.class, new VPackSerializer<MyObject>() { @Override public void serialize( final VPackBuilder builder, final String attribute, final MyObject value, final VPackSerializationContext context) throws VPackException { builder.add(attribute, ValueType.OBJECT); builder.add("name", value.getName()); builder.close(); } }).build();Deserialization using builders is supported using the following annotations:
It allows specifying the builder setters and build method. It has the following fields:
buildMethodName: String: the build method to call on the builder object after having set all the attributeswithSetterPrefix: String: the prefix of the builder setters
This annotation can target:
- the builder class having a public no-arg constructor, eg:
@VPackPOJOBuilder(buildMethodName = "build", withSetterPrefix = "set") public class Builder { public Builder() { // ... } public MyClass build() { // ... } // ... }- a public static factory method which returns the builder, eg:
public class MyClass { @VPackPOJOBuilder(buildMethodName = "build", withSetterPrefix = "with") public static Builder<MyClass> builder() { //... } // ... }It allows to specify the builder class that will be used during the deserialization. It has the following fields:
builder: Class<?>: builder class to usebuilderConfig: VPackPOJOBuilder: it allows specifying the builder setters and build method, useful in case the builder code is auto generated and you cannot add@VPackPOJOBuilderto it.
This annotation can target:
setter: allows specifying the builder for the setter argumentfield: allows specifying the builder for the fieldclass: allows specifying the builder for the classparameter: allows specifying the builder for a constructor (or factory method) parameter
Example:
@VPackDeserialize(builder = MyClassBuilder.class, builderConfig = @VPackPOJOBuilder(buildMethodName = "build", withSetterPrefix = "with")) public class MyClass { // ... } Deserialization using All-Arguments-Constructor is supported annotating the constructor with @VPackCreator and annotating each of its parameters with @SerializedName("name"), eg:
public class Person { private final String name; private final int age; @VPackCreator public Person( @SerializedName("name") String name, @SerializedName("age") int age ) { this.name = name; this.age = age; } // ... }Deserialization using Static Factory Method is supported annotating the method with @VPackCreator and annotating each of its parameters with @SerializedName("name"), eg:
public class Person { private final String name; private final int age; private Person(String name, int age) { this.name = name; this.age = age; } @VPackCreator public static Person of( @SerializedName("name") String name, @SerializedName("age") int age ) { return new Person(name, age); } // ... }Deserialization of Kotlin data classes is supported annotating the constructor with @VPackCreator and annotating each of its parameters with @SerializedName("name"), eg:
data class Person @VPackCreator constructor( @SerializedName("name") val name: String, @SerializedName("age") val age: Int )Deserialization of Scala case classes is supported annotating the constructor with @VPackCreator and annotating each of its parameters with @SerializedName("name"), eg:
case class CasePerson @VPackCreator()( @SerializedName("name") val name: String, @SerializedName("age") val age: Int )