Note: this version contains a bug that prevents usage with Android Java only projects. Use 3.0.1 instead.

• A new Query API is available that works similar to the ObjectBox for Dart/Flutter Query API and makes it easier to create nested conditions. #201

  // equal AND (less OR oneOf)
  val query = box.query(
        User_.firstName equal "Joe"
                and (User_.age less 12
                or (User_.stamp oneOf longArrayOf(1012))))
        .order(User_.age)
        .build()

• For the existing Query API, String property conditions now require to explicitly specify case. See the documentation of StringOrder for which one to choose (typically StringOrder.CASE_INSENSITIVE).

  // Replace String conditions like
  query().equal(User_.firstName, "Joe")
  // With the one accepting a StringOrder
  query().equal(User_.firstName, "Joe", StringOrder.CASE_INSENSITIVE)

• The Gradle plugin will now warn when an @Entity class is missing a no-arg (easy to add) or all properties (best for performance) constructor. #900
  Example for an all properties constructor:

  @Entity
  public class Order {
  
      @Id
      private long id;
      private ToOne<Customer> customer;
      private ToMany<Order> relatedOrders;
  
      // All properties constructor for ObjectBox:
      // - make sure type matches exactly,
      // - for ToOne add its virtual ID property instead,
      // - for ToMany add no parameter.
      public Order(long id, long customerId) {
          this.id = id;
          this.customer.setTargetId(customerId);
      }
  
      // TODO getters and setters for properties
  }

• Subscriptions now publish results in serial instead of in parallel (using a single thread vs. multiple threads per publisher). Publishing in parallel could previously lead to outdated results getting delivered after the latest results. As a side-effect transformers now run in serial instead of in parallel as well (on the same single thread per publisher). #793
• Support annotating a single property with @Unique(onConflict = ConflictStrategy.REPLACE) to replace an existing Object if a conflict occurs when doing a put. #509

  @Entity
  data class Example(
          @Id
          var id: Long = 0,
          @Unique(onConflict = ConflictStrategy.REPLACE)
          var uniqueKey: String? = null
  )

• Support @Unsigned to indicate that values of an integer property (e.g. Integer and Long in Java) should be treated as unsigned when doing queries or creating indexes.
• Store time in nanoseconds using the new @Type annotation:

  @Type(DatabaseType.DateNano)
  var timeInNanos: Long;

• Package FlatBuffers version into library to avoid conflicts with apps or other libraries using FlatBuffers. #894
• Kotlin: add Flow extension functions for BoxStore and Query. #990
• Data browser: display query results if a property has a NaN value. #984
• Android 12: support using Data Browser if targeting Android 12 (SDK 31). #1007

New supported property types

• String arrays (Java String[] and Kotlin Array<String>) and lists (Java List<String> and Kotlin MutableList<String>). Using the new containsElement("item") condition, it is also possible to query for entities where "item" is equal to one of the elements.

  @Entity
  data class Example(
          @Id
          var id: Long = 0,
          var stringArray: Array<String>? = null,
          var stringMap: MutableMap<String, String>? = null
  )
  
  // matches [“first”, “second”, “third”]
  box.query(Example_.stringArray.containsElement(“second”)).build()

• String maps (Java Map<String, String> or Kotlin MutableMap<String, String>). Stored internally as a byte array using FlexBuffers.
• Flexible maps:
  • map keys must all have the same type,
  • map keys or values must not be null,
  • map values must be one of the supported database type, or a list of them (e.g. String, Boolean, Integer, Double, byte array...).

Sync

• The generated JSON model file no longer contains Java-specific flags that would lead to errors if used with Sync server.
• Additional checks when calling client or server methods.

All release notes & docs