APIMBeanIntrospector: Creating an introspector for the MBeanserver

The MX4J introspector does not support *MXBean interfaces name, This
causes a problem with the garbage collector and java related MBeans.

To bypass that limitation the APIMBeanIntrospector inherit from
MBeanIntrospector and override the relevant functionality so MXBean
will be treated like MBean.

Signed-off-by: Amnon Heiman <amnon@scylladb.com>

src/main/java/com/scylladb/jmx/utils/APIMBeanIntrospector.java

@@ -0,0 +1,103 @@
+package com.scylladb.jmx.utils;
+/**
+ * Copyright (C) The MX4J Contributors.
+ * All rights reserved.
+ *
+ * This software is distributed under the terms of the MX4J License version 1.0.
+ * See the terms of the MX4J License in the documentation provided with this software.
+ */
+
+/**
+ * Modified by ScyllaDB
+ * Copyright 2016 ScyllaDB
+ */
+/*
+* This file is part of Scylla.
+*
+* Scylla is free software: you can redistribute it and/or modify
+* it under the terms of the GNU Affero General Public License as published by
+* the Free Software Foundation, either version 3 of the License, or
+* (at your option) any later version.
+*
+* Scylla is distributed in the hope that it will be useful,
+* but WITHOUT ANY WARRANTY; without even the implied warranty of
+* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+* GNU General Public License for more details.
+*
+* You should have received a copy of the GNU General Public License
+* along with Scylla.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+
+import javax.management.MBeanInfo;
+
+import mx4j.server.MBeanIntrospector;
+import mx4j.server.MBeanMetaData;
+
+public class APIMBeanIntrospector extends MBeanIntrospector {
+    private static final java.util.logging.Logger logger = java.util.logging.Logger
+            .getLogger(APIMBeanIntrospector.class.getName());
+
+    public boolean isMBeanCompliant(MBeanMetaData metadata) {
+        Class info = metadata.getMBeanInterface();
+        if (info != null) {
+            String cn = info.getName();
+            if (cn != null) {
+                if (cn.endsWith("MXBean")) {
+                    return true;
+                }
+            }
+        }
+        return super.isMBeanCompliant(metadata);
+    }
+
+    public void apiIntrospectStandardMBean(MBeanMetaData metadata) {
+        try {
+            Class[] cArg = new Class[1];
+            cArg[0] = MBeanMetaData.class;
+            Method met = MBeanIntrospector.class
+                    .getDeclaredMethod("introspectStandardMBean", cArg);
+            met.setAccessible(true);
+            met.invoke((MBeanIntrospector) this, metadata);
+        } catch (NoSuchMethodException | SecurityException
+                | IllegalAccessException | IllegalArgumentException
+                | InvocationTargetException e) {
+            logger.warning("Failed setting mbean info " + e.getMessage());
+        }
+    }
+
+    public void apiIntrospect(MBeanMetaData metadata) {
+        apiIntrospectStandardMBean(metadata);
+        Class[] cArg = new Class[1];
+        cArg[0] = MBeanMetaData.class;
+        try {
+            Method met = MBeanIntrospector.class
+                    .getDeclaredMethod("createStandardMBeanInfo", cArg);
+            met.setAccessible(true);
+            Object info = met.invoke((MBeanIntrospector) this, metadata);
+            metadata.setMBeanInfo((MBeanInfo) info);
+        } catch (IllegalAccessException | NoSuchMethodException
+                | SecurityException | IllegalArgumentException
+                | InvocationTargetException e) {
+            logger.warning("Failed setting mbean info" + e.getMessage());
+        }
+    }
+
+    public void introspect(MBeanMetaData metadata) {
+        Class<?> mx_mbean = null;
+        for (Class<?> it : metadata.getMBean().getClass().getInterfaces()) {
+            if (it.getName().endsWith("MXBean")) {
+                mx_mbean = it;
+                break;
+            }
+        }
+        if (mx_mbean != null) {
+            metadata.setMBeanInterface(mx_mbean);
+            apiIntrospect(metadata);
+            return;
+        }
+        super.introspect(metadata);
+    }
+}