Package space.arim.dazzleconf.engine.liaison

Class MapLiaison

java.lang.Object
space.arim.dazzleconf.engine.liaison.MapLiaison
All Implemented Interfaces:
TypeLiaison
public final class MapLiaison extends Object implements TypeLiaison
Liaison for maps.

This liaison will match all Map<K, V>. It will use the relevant serializers for the key and value type, respectively, to build the relevant map.

Limitations

This liaison does not, and cannot, preserve entry metadata, such as comments, on map values across separate acts of deserialization and serialization. Only a SerializeDeserialize.deserializeUpdate(space.arim.dazzleconf.engine.DeserializeInput, space.arim.dazzleconf.engine.SerializeOutput) operation can preserve this entry metadata.

Duplicate Keys

Note that despite this liaison using a DataTree as its input, it is still possible for keys to be deserialized in a way that produces duplicates. Deserialization, in general, is not a 1-to-1 mapping, and the key type can implement different equality semantics than the input data, in addition to mapping from different input types. For example, "1" and 1 might both be deserialized as 1.

The policy of this liaison is to silently skip keys that become duplicated due to deserialization. This behavior was chosen because such duplication usually arises from user input. There is no sort of "merge" algorithm for values; additionally, it is not defined which key will be selected.

Serialization can also produce duplicate keys. This can happen if the key serializer implementation chooses to produce identical output keys, either during regular serialization or during a read-update operation via SerializeDeserialize.deserializeUpdate(DeserializeInput, SerializeOutput). This liaison considers such duplication a mistake, and it will throw a DeveloperMistakeException if conflicting output keys are detected.

Consistent Order

This liaison provides a consistent order across deserialization and re-serialization. It is implemented internally over an immutable wrapper of LinkedHashSet.

  • Constructor Details

    • MapLiaison

      public MapLiaison()
      Creates the liaison

  • Method Details

    • makeAgent

      @SideEffectFree public <V> @Nullable TypeLiaison.Agent<V> makeAgent(@NonNull TypeToken<V> typeToken, @NonNull TypeLiaison.Handshake handshake)
      Description copied from interface: TypeLiaison
      Attempts to support the following type.

      If supported, an agent is returned that handles type serialization, deserialization, and defaults. Note that implementations may need casting at the source level to satisfy the generic argument of the token requested.

      Specified by:
      makeAgent in interface TypeLiaison
      Type Parameters:
      V - the type being requested
      Parameters:
      typeToken - the type token
      handshake - the handshake
      Returns:
      the agent if supported, or null otherwise