Java example source code file (RandomMXBeanTest.java)

This example Java source code file (RandomMXBeanTest.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

class, dullinvocationhandler, exception, management, map, method, object, objectname, referimpl, refermxbean, reflection, stupidimpl, stupidmxbean, throwable, util, wrapinvocationhandler, zero

The RandomMXBeanTest.java Java example source code

/*
 * Copyright (c) 2006, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 *
 * This code 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
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

/* This test essentially duplicates the functionality of MXBeanTest.java.
 * See LeakTest.java for an explanation.
 */

import java.lang.reflect.Field;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.util.HashMap;
import java.util.Map;
import javax.management.InstanceAlreadyExistsException;
import javax.management.JMX;
import javax.management.MBeanRegistrationException;
import javax.management.MBeanServer;
import javax.management.MBeanServerFactory;
import javax.management.MalformedObjectNameException;
import javax.management.NotCompliantMBeanException;
import javax.management.ObjectName;

public class RandomMXBeanTest {
    public static interface StupidMXBean {
        public int ZERO = Integer.parseInt("0");
        public int getZero();
        public int identity(int x);
    }

    public static class StupidImpl implements StupidMXBean {
        public int getZero() {
            return 0;
        }

        public int identity(int x) {
            return x;
        }
    }

    public static interface ReferMXBean {
        public StupidMXBean getStupid();
    }

    public static class ReferImpl implements ReferMXBean {
        private final StupidMXBean stupid;

        ReferImpl(StupidMXBean stupid) {
            this.stupid = stupid;
        }

        public StupidMXBean getStupid() {
            return stupid;
        }
    }

    private static class WrapInvocationHandler implements InvocationHandler {
        private final Object wrapped;

        WrapInvocationHandler(Object wrapped) {
            this.wrapped = wrapped;
        }

        public Object invoke(Object proxy, Method method, Object[] args)
        throws Throwable {
            return method.invoke(wrapped, args);
        }
    }

    private static class DullInvocationHandler implements InvocationHandler {
        private static Map<Class zeroMap =
                new HashMap<Class();
        static {
            zeroMap.put(byte.class, (byte) 0);
            zeroMap.put(int.class, 0);
            zeroMap.put(short.class, (short) 0);
            zeroMap.put(long.class, 0L);
            zeroMap.put(float.class, 0F);
            zeroMap.put(double.class, 0.0);
            zeroMap.put(boolean.class, false);
            zeroMap.put(char.class, '\0');
        }

        public static Object zeroFor(Class<?> c) {
            if (c.isPrimitive())
                return zeroMap.get(c);
            else
                return null;
        }

        public Object invoke(Object proxy, Method method, Object[] args)
        throws Throwable {
            Class<?> retType = method.getReturnType();
            if (!retType.isPrimitive())
                return null;
            return zeroMap.get(retType);
        }
    }

    public static void main(String[] args) throws Exception {
        MBeanServer mbs = MBeanServerFactory.newMBeanServer();
        ObjectName name = new ObjectName("a:b=c");
        StupidMXBean stupid = new StupidImpl();
        mbs.registerMBean(stupid, name);
        ObjectName referName = new ObjectName("a:c=d");
        mbs.registerMBean(new ReferImpl(stupid), referName);
        System.out.println(mbs.getMBeanInfo(name));
        StupidMXBean stupid2 = (StupidMXBean)
                Proxy.newProxyInstance(StupidMXBean.class.getClassLoader(),
                    new Class<?>[] {StupidMXBean.class},
                    new WrapInvocationHandler(stupid));
        ObjectName stupidName2 = new ObjectName("a:d=e");
        mbs.registerMBean(stupid2, stupidName2);
        Field zero = StupidMXBean.class.getField("ZERO");
        System.out.println("Zero field = " + zero.get(null));
        test(mbs, MerlinMXBean.class);
        test(mbs, TigerMXBean.class);

        StupidMXBean proxy = JMX.newMXBeanProxy(mbs, name, StupidMXBean.class);
        System.out.println("Zero = " + proxy.getZero());
        System.out.println("One = " + proxy.identity(1));
        ReferMXBean referProxy =
                JMX.newMXBeanProxy(mbs, referName, ReferMXBean.class);
        StupidMXBean stupidProxy2 = referProxy.getStupid();
        System.out.println("Same proxy: " + (proxy == stupidProxy2));
        Method[] methods = StupidMXBean.class.getMethods();
        for (Method method : methods) {
            if (method.getParameterTypes().length == 0)
                method.invoke(proxy, new Object[0]);
        }
    }

    private static <T> void test(MBeanServer mbs, Class c) throws Exception {
        System.out.println("Testing " + c.getName());
        T merlin = c.cast(
            Proxy.newProxyInstance(c.getClassLoader(),
                new Class<?>[] {c},
                new DullInvocationHandler()));
        ObjectName merlinName = new ObjectName("a:type=" + c.getName());
        mbs.registerMBean(merlin, merlinName);
        System.out.println(mbs.getMBeanInfo(merlinName));
        T merlinProxy = JMX.newMXBeanProxy(mbs, merlinName, c);
        Method[] merlinMethods = c.getMethods();
        for (Method m : merlinMethods) {
            Class<?>[] types = m.getParameterTypes();
            Object[] params = new Object[types.length];
            for (int i = 0; i < types.length; i++)
                params[i] = DullInvocationHandler.zeroFor(types[i]);
            System.out.println("Invoking " + m.getName());
            m.invoke(merlinProxy, (Object[]) params);
        }
    }
}