refactor: use Subscribable instead of Observer

* this allows for property-specific updates
MovingBlocks · Apr 7, 2024 · c1eeb55 · c1eeb55
1 parent 1f2d83c
commit c1eeb55
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Showing 4 changed files with 70 additions and 20 deletions.
diff --git a/...rc/main/java/org/terasology/engine/rendering/nui/layers/mainMenu/UniverseSetupScreen.java b/...rc/main/java/org/terasology/engine/rendering/nui/layers/mainMenu/UniverseSetupScreen.java
@@ -78,6 +78,8 @@
 import org.terasology.reflection.reflect.ReflectFactory;
 import org.terasology.reflection.reflect.ReflectionReflectFactory;
 
+import java.beans.PropertyChangeEvent;
+import java.beans.PropertyChangeListener;
 import java.nio.ByteBuffer;
 import java.util.HashSet;
 import java.util.List;
@@ -91,7 +93,7 @@
  * Sets up the Universe for a user. Displays a list of {@link WorldGenerator}
  * for a particular game template.
  */
-public class UniverseSetupScreen extends CoreScreenLayer implements UISliderOnChangeTriggeredListener, Observer<WorldConfigurator> {
+public class UniverseSetupScreen extends CoreScreenLayer implements UISliderOnChangeTriggeredListener, PropertyChangeListener {
     public static final ResourceUrn ASSET_URI = new ResourceUrn("engine:universeSetupScreen");
 
     @In
@@ -307,11 +309,15 @@ public void update(float delta) {
     }
 
     /**
-     Called whenever there's a change to WorldConfigurator
+     Called whenever there's a change to WorldConfigurator properties
+     Provides information about the changed property as well as old and new value in {@link PropertyChangeEvent}
      */
     @Override
-    public void update(WorldConfigurator layer) {
-        previewUpdateRequiredSince = time.getRealTimeInMs();
+    public void propertyChange(PropertyChangeEvent propertyChangeEvent) {
+        System.out.println(propertyChangeEvent.getPropertyName());
+        if (propertyChangeEvent.getPropertyName() == "Trees") {
+            previewUpdateRequiredSince = time.getRealTimeInMs();
+        }
     }
 
     private void setSeed(String value) {
@@ -498,7 +504,7 @@ private void configureProperties() {
             worldConfig = worldGenerator.getConfigurator();
             universe.setWorldConfigurator(worldConfig);
         }
-        worldConfig.addObserver(this);
+        worldConfig.subscribe(this);
 
         Map<String, Component> params = worldConfig.getProperties();
 

diff --git a/engine/src/main/java/org/terasology/engine/world/generation/FacetedWorldConfigurator.java b/engine/src/main/java/org/terasology/engine/world/generation/FacetedWorldConfigurator.java
@@ -3,14 +3,20 @@
 package org.terasology.engine.world.generation;
 
 import com.google.common.collect.Maps;
+import com.google.common.collect.Multimap;
+import com.google.common.collect.Multiset;
+import com.google.common.collect.SetMultimap;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.terasology.engine.core.Observer;
 import org.terasology.engine.world.generator.WorldConfigurator;
 import org.terasology.gestalt.entitysystem.component.Component;
 
+import java.beans.PropertyChangeEvent;
+import java.beans.PropertyChangeListener;
 import java.util.ArrayList;
 import java.util.Collections;
+import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
@@ -23,7 +29,7 @@ public class FacetedWorldConfigurator implements WorldConfigurator {
     private final Map<String, Component> properties = Maps.newHashMap();
 
     private final List<ConfigurableFacetProvider> providers;
-    private Set<Observer<WorldConfigurator>> observers = new HashSet<>();
+    private HashMap<String, Set<PropertyChangeListener>> listeners = new HashMap<>();
 
     public FacetedWorldConfigurator(List<ConfigurableFacetProvider> providersList) {
         for (ConfigurableFacetProvider provider : providersList) {
@@ -45,10 +51,22 @@ public void setProperty(String key, Component comp) {
         for (ConfigurableFacetProvider facetProvider : providers) {
             if (key.equals(facetProvider.getConfigurationName())) {
                 facetProvider.setConfiguration(comp);
+                Component oldComp = properties.get(key);
                 properties.put(key, comp);
-                observers.forEach(observer -> {
-                    observer.update(this);
-                });
+
+                PropertyChangeEvent event = new PropertyChangeEvent(this, key, oldComp, comp);
+                Set<PropertyChangeListener> allPropListeners = listeners.get("*");
+                if (allPropListeners != null) {
+                    allPropListeners.forEach(listener -> {
+                        listener.propertyChange(event);
+                    });
+                }
+                Set<PropertyChangeListener> specPropListeners = listeners.get(key);
+                if (specPropListeners != null) {
+                    specPropListeners.forEach(listener -> {
+                        listener.propertyChange(event);
+                    });
+                }
                 return;
             }
         }
@@ -57,12 +75,30 @@ public void setProperty(String key, Component comp) {
     }
 
     @Override
-    public void addObserver(Observer<WorldConfigurator> observer) {
-        observers.add(observer);
+    public void subscribe(PropertyChangeListener changeListener) {
+        Set<PropertyChangeListener> ls = listeners.computeIfAbsent("*", k -> new HashSet<>());
+        ls.add(changeListener);
+    }
+
+    @Override
+    public void unsubscribe(PropertyChangeListener changeListener) {
+        listeners.computeIfPresent("*", (k, v) -> {
+            v.remove(changeListener);
+            return v;
+        });
+    }
+
+    @Override
+    public void subscribe(String propertyName, PropertyChangeListener changeListener) {
+        Set<PropertyChangeListener> ls = listeners.computeIfAbsent(propertyName, k -> new HashSet<>());
+        ls.add(changeListener);
     }
 
     @Override
-    public void removeObserver(Observer<WorldConfigurator> observer) {
-        observers.remove(observer);
+    public void unsubscribe(String propertyName, PropertyChangeListener changeListener) {
+        listeners.computeIfPresent(propertyName, (k, v) -> {
+            v.remove(changeListener);
+            return v;
+        });
     }
 }
diff --git a/engine/src/main/java/org/terasology/engine/world/generator/WorldConfigurator.java b/engine/src/main/java/org/terasology/engine/world/generator/WorldConfigurator.java
@@ -3,6 +3,7 @@
 package org.terasology.engine.world.generator;
 
 import org.terasology.engine.core.Observer;
+import org.terasology.engine.utilities.subscribables.Subscribable;
 import org.terasology.gestalt.entitysystem.component.Component;
 
 import java.util.Map;
@@ -11,7 +12,7 @@
 /**
  * Allows for configuration of world generators.
  */
-public interface WorldConfigurator {
+public interface WorldConfigurator extends Subscribable {
 
     /**
      * The values are supposed to be annotated with {@link org.terasology.nui.properties.Property}
@@ -25,8 +26,4 @@ public interface WorldConfigurator {
      * @param comp the configuration component
      */
     void setProperty(String key, Component comp);
-
-    void addObserver(Observer<WorldConfigurator> observer);
-
-    void removeObserver(Observer<WorldConfigurator> observer);
 }
diff --git a/engine/src/main/java/org/terasology/engine/world/generator/WorldConfiguratorAdapter.java b/engine/src/main/java/org/terasology/engine/world/generator/WorldConfiguratorAdapter.java
@@ -5,6 +5,7 @@
 import org.terasology.engine.core.Observer;
 import org.terasology.gestalt.entitysystem.component.Component;
 
+import java.beans.PropertyChangeListener;
 import java.util.Collections;
 import java.util.Map;
 
@@ -24,12 +25,22 @@ public void setProperty(String key, Component comp) {
     }
 
     @Override
-    public void addObserver(Observer<WorldConfigurator> observer) {
+    public void subscribe(PropertyChangeListener changeListener) {
         // simply ignore
     }
 
     @Override
-    public void removeObserver(Observer<WorldConfigurator> observer) {
+    public void unsubscribe(PropertyChangeListener changeListener) {
+        // simply ignore
+    }
+
+    @Override
+    public void subscribe(String propertyName, PropertyChangeListener changeListener) {
+        // simply ignore
+    }
+
+    @Override
+    public void unsubscribe(String propertyName, PropertyChangeListener changeListener) {
         // simply ignore
     }
 }