* Add PointerBufferPoolMXBean to track allocations and deallocatio…

…ns of `Pointer` (pull #413)

src/main/java/org/bytedeco/javacpp/Pointer.java

@@ -33,8 +33,8 @@
 import java.util.Iterator;
 import java.util.concurrent.atomic.AtomicInteger;
 import org.bytedeco.javacpp.annotation.Name;
-import org.bytedeco.javacpp.annotation.Platform;
 import org.bytedeco.javacpp.tools.Generator;
+import org.bytedeco.javacpp.tools.PointerBufferPoolMXBean;
 import org.bytedeco.javacpp.tools.Logger;
 
 /**
@@ -285,6 +285,7 @@ static class DeallocatorReference extends PhantomReference<Pointer> implements D
         Deallocator deallocator;
 
         static volatile long totalBytes = 0;
+        static volatile long totalCount = 0;
         long bytes;
 
         AtomicInteger count;
@@ -298,6 +299,7 @@ final void add() {
                     next.prev = head = this;
                 }
                 totalBytes += bytes;
+                totalCount++;
             }
         }
 
@@ -316,6 +318,7 @@ final void remove() {
                 }
                 prev = next = this;
                 totalBytes -= bytes;
+                totalCount--;
             }
         }
 
@@ -506,6 +509,11 @@ public static long parseBytes(String string, long relativeMultiple) throws Numbe
         } catch (Throwable t) {
             logger.warn("Could not load Pointer: " + t);
         }
+
+        String mx = System.getProperty("org.bytedeco.javacpp.mxbean", "false").toLowerCase();
+        if (mx.equals("true") || mx.equals("t") || mx.equals("")) {
+            PointerBufferPoolMXBean.register();
+        }
     }
 
     /** Clears, deallocates, and removes all garbage collected objects from the {@link #referenceQueue}. */
@@ -527,6 +535,11 @@ public static long totalBytes() {
         return DeallocatorReference.totalBytes;
     }
 
+    /** Returns {@link DeallocatorReference#totalCount}, current number of pointers tracked by deallocators. */
+    public static long totalCount() {
+        return DeallocatorReference.totalCount;
+    }
+
     /** Returns {@link #maxPhysicalBytes}, the maximum amount of physical memory that should be used. */
     public static long maxPhysicalBytes() {
         return maxPhysicalBytes;

src/main/java/org/bytedeco/javacpp/tools/PointerBufferPoolMXBean.java

@@ -0,0 +1,59 @@
+package org.bytedeco.javacpp.tools;
+
+import org.bytedeco.javacpp.Pointer;
+
+import javax.management.*;
+import java.lang.management.BufferPoolMXBean;
+import java.lang.management.ManagementFactory;
+
+public class PointerBufferPoolMXBean implements BufferPoolMXBean {
+
+    private static final Logger LOGGER = Logger.create(PointerBufferPoolMXBean.class);
+    private static final String JAVACPP_MXBEAN_NAME = "javacpp";
+    private static final ObjectName OBJECT_NAME;
+
+    static {
+        ObjectName objectName = null;
+        try {
+            objectName = new ObjectName("java.nio:type=BufferPool,name=" + JAVACPP_MXBEAN_NAME);
+        } catch (MalformedObjectNameException e) {
+            LOGGER.warn("Could not create OBJECT_NAME for " + JAVACPP_MXBEAN_NAME);
+        }
+        OBJECT_NAME = objectName;
+    }
+
+    @Override
+    public String getName() {
+        return JAVACPP_MXBEAN_NAME;
+    }
+
+    @Override
+    public ObjectName getObjectName() {
+        return OBJECT_NAME;
+    }
+
+    @Override
+    public long getCount() {
+        return Pointer.totalCount();
+    }
+
+    @Override
+    public long getTotalCapacity() {
+        return Pointer.maxPhysicalBytes();
+    }
+
+    @Override
+    public long getMemoryUsed() {
+        return Pointer.totalBytes();
+    }
+
+    public static void register() {
+        if (OBJECT_NAME != null) {
+            try {
+                ManagementFactory.getPlatformMBeanServer().registerMBean(new PointerBufferPoolMXBean(), OBJECT_NAME);
+            } catch (InstanceAlreadyExistsException | MBeanRegistrationException | NotCompliantMBeanException e) {
+                LOGGER.warn("Could not register " + JAVACPP_MXBEAN_NAME + " BufferPoolMXBean");
+            }
+        }
+    }
+}