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package com.sun.jmx.mbeanserver;

import static com.sun.jmx.mbeanserver.Util.*;

import java.util.Iterator;
import java.util.Set;

import javax.management.InstanceAlreadyExistsException;
import javax.management.JMX;
import javax.management.MBeanServer;
import javax.management.NotCompliantMBeanException;
import javax.management.ObjectName;

Base class for MXBeans.
Since:1.6
/** * Base class for MXBeans. * * @since 1.6 */
public class MXBeanSupport extends MBeanSupport<ConvertingMethod> {

Construct an MXBean that wraps the given resource using the given MXBean interface.

Params:
  • resource – the underlying resource for the new MXBean.
  • mxbeanInterface – the interface to be used to determine the MXBean's management interface.
Type parameters:
  • <T> – a type parameter that allows the compiler to check that resource implements mxbeanInterface, provided that mxbeanInterface is a class constant like SomeMXBean.class.
Throws:
  • IllegalArgumentException – if resource is null or if it does not implement the class mxbeanInterface or if that class is not a valid MXBean interface.
/** <p>Construct an MXBean that wraps the given resource using the given MXBean interface.</p> @param resource the underlying resource for the new MXBean. @param mxbeanInterface the interface to be used to determine the MXBean's management interface. @param <T> a type parameter that allows the compiler to check that {@code resource} implements {@code mxbeanInterface}, provided that {@code mxbeanInterface} is a class constant like {@code SomeMXBean.class}. @throws IllegalArgumentException if {@code resource} is null or if it does not implement the class {@code mxbeanInterface} or if that class is not a valid MXBean interface. */
public <T> MXBeanSupport(T resource, Class<T> mxbeanInterface) throws NotCompliantMBeanException { super(resource, mxbeanInterface); } @Override MBeanIntrospector<ConvertingMethod> getMBeanIntrospector() { return MXBeanIntrospector.getInstance(); } @Override Object getCookie() { return mxbeanLookup; } static Class<?> findMXBeanInterface(Class<?> resourceClass) throws IllegalArgumentException { if (resourceClass == null) throw new IllegalArgumentException("Null resource class"); final Set<Class<?>> intfs = transitiveInterfaces(resourceClass); final Set<Class<?>> candidates = newSet(); for (Class<?> intf : intfs) { if (JMX.isMXBeanInterface(intf)) candidates.add(intf); } reduce: while (candidates.size() > 1) { for (Class<?> intf : candidates) { for (Iterator<Class<?>> it = candidates.iterator(); it.hasNext(); ) { final Class<?> intf2 = it.next(); if (intf != intf2 && intf2.isAssignableFrom(intf)) { it.remove(); continue reduce; } } } final String msg = "Class " + resourceClass.getName() + " implements more than " + "one MXBean interface: " + candidates; throw new IllegalArgumentException(msg); } if (candidates.iterator().hasNext()) { return candidates.iterator().next(); } else { final String msg = "Class " + resourceClass.getName() + " is not a JMX compliant MXBean"; throw new IllegalArgumentException(msg); } } /* Return all interfaces inherited by this class, directly or * indirectly through the parent class and interfaces. */ private static Set<Class<?>> transitiveInterfaces(Class c) { Set<Class<?>> set = newSet(); transitiveInterfaces(c, set); return set; } private static void transitiveInterfaces(Class<?> c, Set<Class<?>> intfs) { if (c == null) return; if (c.isInterface()) intfs.add(c); transitiveInterfaces(c.getSuperclass(), intfs); for (Class sup : c.getInterfaces()) transitiveInterfaces(sup, intfs); } /* * The sequence of events for tracking inter-MXBean references is * relatively complicated. We use the magical preRegister2 method * which the MBeanServer knows about. The steps during registration * are: * (1) Call user preRegister, if any. If exception, abandon. * (2) Call preRegister2 and hence this register method. If exception, * call postRegister(false) and abandon. * (3) Try to register the MBean. If exception, call registerFailed() * which will call the unregister method. (Also call postRegister(false).) * (4) If we get this far, we can call postRegister(true). * * When we are wrapped in an instance of javax.management.StandardMBean, * things are simpler. That class calls this method from its preRegister, * and propagates any exception. There is no user preRegister in this case. * If this method succeeds but registration subsequently fails, * StandardMBean calls unregister from its postRegister(false) method. */ @Override public void register(MBeanServer server, ObjectName name) throws InstanceAlreadyExistsException { if (name == null) throw new IllegalArgumentException("Null object name"); // eventually we could have some logic to supply a default name synchronized (lock) { if (this.objectName != null) { final String msg = "MXBean already registered with name " + this.objectName; throw new InstanceAlreadyExistsException(msg); } this.mxbeanLookup = MXBeanLookup.lookupFor(server); this.mxbeanLookup.addReference(name, getResource()); this.objectName = name; } } @Override public void unregister() { synchronized (lock) { if (mxbeanLookup.removeReference(objectName, getResource())) objectName = null; } } private Object lock = new Object(); // for mxbeanLookup and objectName private MXBeanLookup mxbeanLookup; private ObjectName objectName; }