- add way to release direct memory, including test

git-svn-id: https://jmonkeyengine.googlecode.com/svn/trunk@8976 75d07b2b-3a1a-0410-a2c5-0572b91ccdca

engine/src/core/com/jme3/util/BufferUtils.java

@@ -35,11 +35,15 @@ import com.jme3.math.ColorRGBA;
 import com.jme3.math.Quaternion;
 import com.jme3.math.Vector2f;
 import com.jme3.math.Vector3f;
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
 import java.nio.*;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.Map;
 import java.util.WeakHashMap;
+import java.util.logging.Level;
+import java.util.logging.Logger;
 
 /**
  * <code>BufferUtils</code> is a helper class for generating nio buffers from
@@ -1139,4 +1143,38 @@ public final class BufferUtils {
             System.out.println(store.toString());
         }
     }
+    
+    /**
+    * DirectByteBuffers are garbage collected by using a phantom reference and a
+    * reference queue. Every once a while, the JVM checks the reference queue and
+    * cleans the DirectByteBuffers. However, as this doesn't happen
+    * immediately after discarding all references to a DirectByteBuffer, it's
+    * easy to OutOfMemoryError yourself using DirectByteBuffers. This function
+    * explicitly calls the Cleaner method of a DirectByteBuffer.
+    * 
+    * @param toBeDestroyed
+    *          The DirectByteBuffer that will be "cleaned". Utilizes reflection.
+    *          
+    */
+    public static void destroyDirectByteBuffer(ByteBuffer toBeDestroyed) {
+        try {
+            Method cleanerMethod = toBeDestroyed.getClass().getMethod("cleaner");
+            cleanerMethod.setAccessible(true);
+            Object cleaner = cleanerMethod.invoke(toBeDestroyed);
+            Method cleanMethod = cleaner.getClass().getMethod("clean");
+            cleanMethod.setAccessible(true);
+            cleanMethod.invoke(cleaner);
+        } catch (IllegalAccessException ex) {
+            Logger.getLogger(BufferUtils.class.getName()).log(Level.SEVERE, "{0}", ex);
+        } catch (IllegalArgumentException ex) {
+            Logger.getLogger(BufferUtils.class.getName()).log(Level.SEVERE, "{0}", ex);
+        } catch (InvocationTargetException ex) {
+            Logger.getLogger(BufferUtils.class.getName()).log(Level.SEVERE, "{0}", ex);
+        } catch (NoSuchMethodException ex) {
+            Logger.getLogger(BufferUtils.class.getName()).log(Level.SEVERE, "{0}", ex);
+        } catch (SecurityException ex) {
+            Logger.getLogger(BufferUtils.class.getName()).log(Level.SEVERE, "{0}", ex);
+        }
+    }
+
 }

engine/src/test/jme3test/app/TestReleaseDirectMemory.java

@@ -0,0 +1,70 @@
+/*
+ * Copyright (c) 2009-2010 jMonkeyEngine
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ * * Redistributions of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ *
+ * * Redistributions in binary form must reproduce the above copyright
+ *   notice, this list of conditions and the following disclaimer in the
+ *   documentation and/or other materials provided with the distribution.
+ *
+ * * Neither the name of 'jMonkeyEngine' nor the names of its contributors
+ *   may be used to endorse or promote products derived from this software
+ *   without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+ * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+package jme3test.app;
+
+import jme3test.model.shape.*;
+import com.jme3.app.SimpleApplication;
+import com.jme3.material.Material;
+import com.jme3.math.Vector3f;
+import com.jme3.scene.Geometry;
+import com.jme3.scene.shape.Box;
+import com.jme3.util.BufferUtils;
+import java.lang.reflect.InvocationTargetException;
+import java.nio.ByteBuffer;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+
+public class TestReleaseDirectMemory extends SimpleApplication {
+
+    public static void main(String[] args){
+        TestReleaseDirectMemory app = new TestReleaseDirectMemory();
+        app.start();
+    }
+
+    @Override
+    public void simpleInitApp() {
+        Box b = new Box(Vector3f.ZERO, 1, 1, 1);
+        Geometry geom = new Geometry("Box", b);
+        Material mat = new Material(assetManager, "Common/MatDefs/Misc/Unshaded.j3md");
+        mat.setTexture("ColorMap", assetManager.loadTexture("Interface/Logo/Monkey.jpg"));
+        geom.setMaterial(mat);
+        rootNode.attachChild(geom);
+    }
+
+    @Override
+    public void simpleUpdate(float tpf) {
+        ByteBuffer buf = BufferUtils.createByteBuffer(500000);
+        BufferUtils.destroyDirectByteBuffer(buf);
+    }
+    
+}