Initial contextual data work

src/main/java/org/spongepowered/api/data/DataPerspective.java

@@ -0,0 +1,13 @@
+package org.spongepowered.api.data;
+
+import org.spongepowered.api.data.value.ValueContainer;
+import org.spongepowered.plugin.PluginContainer;
+
+public interface DataPerspective {
+
+    Iterable<DataPerspective> perceives();
+
+    ValueContainer getDataPerception(DataPerspective perspective);
+
+    DataHolder.Mutable createDataPerception(PluginContainer plugin, DataPerspective perspective);
+}

src/main/java/org/spongepowered/api/data/DataPerspectiveResolver.java

@@ -0,0 +1,31 @@
+package org.spongepowered.api.data;
+
+import org.checkerframework.checker.nullness.qual.Nullable;
+import org.spongepowered.api.data.value.Value;
+
+public interface DataPerspectiveResolver<V extends Value<E>, E> {
+
+    /**
+     * Gets the {@link Key} this resolver supports.
+     *
+     * @return The key
+     */
+    Key<V> key();
+
+    /**
+     * When multiple plugins provide the same key this is used to
+     * merge and pick the best.
+     *
+     * @return The merged value
+     */
+    E merge(Iterable<E> values);
+
+    /**
+     * When data holders value changes when looking at perspective of.
+     *
+     * @param dataHolder The data holder which value was overridden.
+     * @param perspective The perspective it is perceived from.
+     * @param value The value.
+     */
+    void apply(DataHolder dataHolder, DataPerspective perspective, @Nullable E value);
+}

src/main/java/org/spongepowered/api/data/DataRegistration.java

@@ -111,6 +111,8 @@ static Builder builder() {
      */
     Optional<DataStore> dataStore(Class<? extends DataHolder> token);
 
+    <V extends Value<E>, E> Optional<DataPerspectiveResolver<V, E>> dataPerspectiveResolverFor(Key<V> key);
+
     /**
      * Gets the registered {@link Key Keys} this controls. Note that each
      * {@link Key} can only be registered/owned by a single
@@ -181,6 +183,8 @@ interface Builder extends org.spongepowered.api.util.Builder<DataRegistration, B
          */
         Builder provider(DataProvider<?, ?> provider) throws DuplicateProviderException;
 
+        Builder perspectiveResolver(DataPerspectiveResolver<?, ?> resolver);
+
         /**
          * Gives the {@link Key} to this builder signifying the key is to be
          * registered either with an applicable {@link DataProvider} or an

src/main/java/org/spongepowered/api/entity/Entity.java

@@ -28,6 +28,7 @@
 import net.kyori.adventure.text.Component;
 import net.kyori.adventure.text.event.HoverEvent;
 import net.kyori.adventure.text.event.HoverEventSource;
+import org.spongepowered.api.data.DataPerspective;
 import org.spongepowered.api.data.Keys;
 import org.spongepowered.api.data.SerializableDataHolder;
 import org.spongepowered.api.data.value.ListValue;
@@ -79,7 +80,7 @@
  */
 @DoNotStore
 public interface Entity extends Identifiable, HoverEventSource<HoverEvent.ShowEntity>, Locatable, EntityProjectileSource, Sound.Emitter,
-        SerializableDataHolder.Mutable, RandomProvider, TeamMember {
+        SerializableDataHolder.Mutable, RandomProvider, TeamMember, DataPerspective {
 
     /**
      * Gets the {@link EntityType}.

src/main/java/org/spongepowered/api/scoreboard/Team.java

@@ -27,6 +27,7 @@
 import net.kyori.adventure.text.Component;
 import net.kyori.adventure.text.format.NamedTextColor;
 import org.spongepowered.api.Sponge;
+import org.spongepowered.api.data.DataPerspective;
 import org.spongepowered.api.entity.living.player.Player;
 import org.spongepowered.api.util.CopyableBuilder;
 
@@ -57,7 +58,7 @@
  * For it to work, both players must have the same scoreboard, and be on a team
  * registered to said scoreboard.</p>
  */
-public interface Team {
+public interface Team extends DataPerspective {
 
     /**
      * Creates a new {@link Builder} to build a {@link Team}.

src/main/java/org/spongepowered/api/world/World.java

@@ -27,6 +27,7 @@
 import net.kyori.adventure.audience.Audience;
 import net.kyori.adventure.audience.ForwardingAudience;
 import org.spongepowered.api.Server;
+import org.spongepowered.api.data.DataPerspective;
 import org.spongepowered.api.effect.Viewer;
 import org.spongepowered.api.entity.Entity;
 import org.spongepowered.api.entity.living.player.Player;
@@ -59,7 +60,8 @@ public interface World<W extends World<W, L>, L extends Location<W, L>> extends
     Viewer,
     ArchetypeVolumeCreator,
     WeatherUniverse,
-    RegistryHolder {
+    RegistryHolder,
+    DataPerspective {
 
     /**
      * Gets the {@link WorldProperties properties}.