Merge pull request rvandoosselaer#15 from rvandoosselaer/feature-page…

…rlistener add a listener that gets triggered when a page is attached, detached and updated.
vxel · Jan 3, 2020 · bccc30e · bccc30e
2 parents 9cf80f5 + 557f723
commit bccc30e
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diff --git a/examples/src/main/java/com/rvandoosselaer/blocks/examples/ProceduralTerrain.java b/examples/src/main/java/com/rvandoosselaer/blocks/examples/ProceduralTerrain.java
@@ -11,6 +11,7 @@
 import com.jme3.math.ColorRGBA;
 import com.jme3.math.Vector2f;
 import com.jme3.math.Vector3f;
+import com.jme3.scene.Node;
 import com.rvandoosselaer.blocks.Block;
 import com.rvandoosselaer.blocks.BlockIds;
 import com.rvandoosselaer.blocks.BlocksConfig;
@@ -19,6 +20,7 @@
 import com.rvandoosselaer.blocks.ChunkManager;
 import com.rvandoosselaer.blocks.ChunkManagerState;
 import com.rvandoosselaer.blocks.ChunkPagerState;
+import com.rvandoosselaer.blocks.PagerListener;
 import com.simsilica.lemur.GuiGlobals;
 import com.simsilica.lemur.style.BaseStyles;
 import com.simsilica.mathd.Vec3i;
@@ -76,6 +78,7 @@ public void simpleInitApp() {
                 .build();
 
         stateManager.attachAll(new ChunkManagerState(chunkManager), new ChunkPagerState(rootNode, chunkManager));
+        stateManager.getState(ChunkPagerState.class).getChunkPager().addListener(new PagerListenerOutput());
 
         hideCursor();
 
@@ -95,6 +98,25 @@ private void hideCursor() {
         inputManager.setCursorVisible(false);
     }
 
+    private static class PagerListenerOutput implements PagerListener<Node> {
+
+        @Override
+        public void onPageDetached(Vec3i location, Node page) {
+            System.out.println("Chunk detached - " + location + " - " + page);
+        }
+
+        @Override
+        public void onPageAttached(Vec3i location, Node page) {
+            System.out.println("Chunk attached - " + location + " - " + page);
+        }
+
+        @Override
+        public void onPageUpdated(Vec3i location, Node oldPage, Node newPage) {
+            System.out.println("Chunk updated - " + location + " - " + " old page: " + oldPage + ", new page: " + newPage);
+        }
+
+    }
+
     private static class ChunkNoiseGenerator implements ChunkGenerator {
 
         private final long seed;

diff --git a/src/main/java/com/rvandoosselaer/blocks/Pager.java b/src/main/java/com/rvandoosselaer/blocks/Pager.java
@@ -11,13 +11,15 @@
 import java.util.Collections;
 import java.util.HashSet;
 import java.util.LinkedList;
+import java.util.List;
 import java.util.Map;
 import java.util.Objects;
 import java.util.Optional;
 import java.util.Queue;
 import java.util.Set;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ConcurrentLinkedQueue;
+import java.util.concurrent.CopyOnWriteArrayList;
 
 /**
  * An abstract implementation of a 3D pager. Based on the given center location ({@link #setLocation(Vector3f)} the pages
@@ -59,6 +61,7 @@ public abstract class Pager<T> {
     @Setter
     protected Vec3i gridUpperBounds = new Vec3i(Integer.MAX_VALUE, Integer.MAX_VALUE, Integer.MAX_VALUE);
     private ChunkManagerListener listener = new ChunkPagerListener();
+    protected List<PagerListener<T>> pagerListeners = new CopyOnWriteArrayList<>();
 
     public void initialize() {
         if (log.isTraceEnabled()) {
@@ -95,6 +98,14 @@ public void cleanup() {
         listener = null;
     }
 
+    public void addListener(@NonNull PagerListener<T> listener) {
+        pagerListeners.add(listener);
+    }
+
+    public void removeListener(@NonNull PagerListener<T> listener) {
+        pagerListeners.remove(listener);
+    }
+
     /**
      * Calculates and returns the pages (chunks) in the grid, based on the gridSize and centerPageLocation in the grid.
      *
@@ -210,6 +221,12 @@ private void detachPageAtLocation(Vec3i pageLocation) {
         // cause problems when a chunk that is attached to the scenegraph is removed from the cache. By manually
         // evicting a chunk that is safely detached, we try to counter this behaviour.
         chunkManager.removeChunk(pageLocation);
+
+        notifyListenersPageDetached(pageLocation, page);
+    }
+
+    private void notifyListenersPageDetached(Vec3i pageLocation, T page) {
+        pagerListeners.forEach(listener -> listener.onPageDetached(pageLocation, page));
     }
 
     /**
@@ -240,6 +257,12 @@ private void attachPageAtLocation(Vec3i pageLocation) {
 
         attachPage(page);
         attachedPages.put(pageLocation, page);
+
+        notifyListenersPageAttached(pageLocation, page);
+    }
+
+    private void notifyListenersPageAttached(Vec3i pageLocation, T page) {
+        pagerListeners.forEach(listener -> listener.onPageAttached(pageLocation, page));
     }
 
     private void requestPage(Vec3i pageLocation) {
@@ -287,6 +310,12 @@ private void updatePages() {
 
         attachPage(newPage);
         attachedPages.put(pageLocation, newPage);
+
+        notifyListenersPageUpdated(pageLocation, oldPage, newPage);
+    }
+
+    private void notifyListenersPageUpdated(Vec3i pageLocation, T oldPage, T newPage) {
+        pagerListeners.forEach(listener -> listener.onPageUpdated(pageLocation, oldPage, newPage));
     }
 
     private void setCenterPage(Vec3i centerPage) {

diff --git a/src/main/java/com/rvandoosselaer/blocks/PagerListener.java b/src/main/java/com/rvandoosselaer/blocks/PagerListener.java
@@ -0,0 +1,19 @@
+package com.rvandoosselaer.blocks;
+
+import com.simsilica.mathd.Vec3i;
+
+/**
+ * A listener that can be registered to the {@link Pager}. Use this to get notified when pages are attached, detached
+ * or updated.
+ *
+ * @author: rvandoosselaer
+ */
+public interface PagerListener<T> {
+
+    void onPageDetached(Vec3i location, T page);
+
+    void onPageAttached(Vec3i location, T page);
+
+    void onPageUpdated(Vec3i location, T oldPage, T newPage);
+
+}