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	/*
	* Copyright (c) 1999, 2013, 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. Oracle designates this
	* particular file as subject to the "Classpath" exception as provided
	* by Oracle in the LICENSE file that accompanied this code.
	*
	* 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.
	*/

	package javax.management;

	import com.sun.jmx.defaults.JmxProperties;
	import static com.sun.jmx.defaults.JmxProperties.JMX_INITIAL_BUILDER;
	import static com.sun.jmx.defaults.JmxProperties.MBEANSERVER_LOGGER;
	import com.sun.jmx.mbeanserver.GetPropertyAction;
	import java.security.AccessController;
	import java.security.Permission;
	import java.util.ArrayList;
	import java.util.logging.Level;
	import javax.management.loading.ClassLoaderRepository;
	import sun.reflect.misc.ReflectUtil;


	/**
	* <p>Provides MBean server references. There are no instances of
	* this class.</p>
	*
	* <p>Since JMX 1.2 this class makes it possible to replace the default
	* MBeanServer implementation. This is done using the
	* {@link javax.management.MBeanServerBuilder} class.
	* The class of the initial MBeanServerBuilder to be
	* instantiated can be specified through the
	* <b>javax.management.builder.initial</b> system property.
	* The specified class must be a public subclass of
	* {@link javax.management.MBeanServerBuilder}, and must have a public
	* empty constructor.
	* <p>By default, if no value for that property is specified, an instance of
	* {@link
	* javax.management.MBeanServerBuilder javax.management.MBeanServerBuilder}
	* is created. Otherwise, the MBeanServerFactory attempts to load the
	* specified class using
	* {@link java.lang.Thread#getContextClassLoader()
	* Thread.currentThread().getContextClassLoader()}, or if that is null,
	* {@link java.lang.Class#forName(java.lang.String) Class.forName()}. Then
	* it creates an initial instance of that Class using
	* {@link java.lang.Class#newInstance()}. If any checked exception
	* is raised during this process (e.g.
	* {@link java.lang.ClassNotFoundException},
	* {@link java.lang.InstantiationException}) the MBeanServerFactory
	* will propagate this exception from within a RuntimeException.</p>
	*
	* <p>The <b>javax.management.builder.initial</b> system property is
	* consulted every time a new MBeanServer needs to be created, and the
	* class pointed to by that property is loaded. If that class is different
	* from that of the current MBeanServerBuilder, then a new MBeanServerBuilder
	* is created. Otherwise, the MBeanServerFactory may create a new
	* MBeanServerBuilder or reuse the current one.</p>
	*
	* <p>If the class pointed to by the property cannot be
	* loaded, or does not correspond to a valid subclass of MBeanServerBuilder
	* then an exception is propagated, and no MBeanServer can be created until
	* the <b>javax.management.builder.initial</b> system property is reset to
	* valid value.</p>
	*
	* <p>The MBeanServerBuilder makes it possible to wrap the MBeanServers
	* returned by the default MBeanServerBuilder implementation, for the purpose
	* of e.g. adding an additional security layer.</p>
	*
	* @since 1.5
	*/
	public class MBeanServerFactory {

	/*
	* There are no instances of this class so don't generate the
	* default public constructor.
	*/
	private MBeanServerFactory() {

	}

	/**
	* The builder that will be used to construct MBeanServers.
	*
	**/
	private static MBeanServerBuilder builder = null;

	/**
	* Provide a new {@link javax.management.MBeanServerBuilder}.
	* @param builder The new MBeanServerBuilder that will be used to
	* create {@link javax.management.MBeanServer}s.
	* @exception IllegalArgumentException if the given builder is null.
	*
	* @exception SecurityException if there is a SecurityManager and
	* the caller's permissions do not include or imply <code>{@link
	* MBeanServerPermission}("setMBeanServerBuilder")</code>.
	*
	**/
	// public static synchronized void
	// setMBeanServerBuilder(MBeanServerBuilder builder) {
	// checkPermission("setMBeanServerBuilder");
	// MBeanServerFactory.builder = builder;
	// }

	/**
	* Get the current {@link javax.management.MBeanServerBuilder}.
	*
	* @return the current {@link javax.management.MBeanServerBuilder}.
	*
	* @exception SecurityException if there is a SecurityManager and
	* the caller's permissions do not include or imply <code>{@link
	* MBeanServerPermission}("getMBeanServerBuilder")</code>.
	*
	**/
	// public static synchronized MBeanServerBuilder getMBeanServerBuilder() {
	// checkPermission("getMBeanServerBuilder");
	// return builder;
	// }

	/**
	* Remove internal MBeanServerFactory references to a created
	* MBeanServer. This allows the garbage collector to remove the
	* MBeanServer object.
	*
	* @param mbeanServer the MBeanServer object to remove.
	*
	* @exception java.lang.IllegalArgumentException if
	* <code>mbeanServer</code> was not generated by one of the
	* <code>createMBeanServer</code> methods, or if
	* <code>releaseMBeanServer</code> was already called on it.
	*
	* @exception SecurityException if there is a SecurityManager and
	* the caller's permissions do not include or imply <code>{@link
	* MBeanServerPermission}("releaseMBeanServer")</code>.
	*/
	public static void releaseMBeanServer(MBeanServer mbeanServer) {
	checkPermission("releaseMBeanServer");

	removeMBeanServer(mbeanServer);
	}

	/**
	* <p>Return a new object implementing the MBeanServer interface
	* with a standard default domain name. The default domain name
	* is used as the domain part in the ObjectName of MBeans when the
	* domain is specified by the user is null.</p>
	*
	* <p>The standard default domain name is
	* <code>DefaultDomain</code>.</p>
	*
	* <p>The MBeanServer reference is internally kept. This will
	* allow <CODE>findMBeanServer</CODE> to return a reference to
	* this MBeanServer object.</p>
	*
	* <p>This method is equivalent to <code>createMBeanServer(null)</code>.
	*
	* @return the newly created MBeanServer.
	*
	* @exception SecurityException if there is a SecurityManager and the
	* caller's permissions do not include or imply <code>{@link
	* MBeanServerPermission}("createMBeanServer")</code>.
	*
	* @exception JMRuntimeException if the property
	* <code>javax.management.builder.initial</code> exists but the
	* class it names cannot be instantiated through a public
	* no-argument constructor; or if the instantiated builder returns
	* null from its {@link MBeanServerBuilder#newMBeanServerDelegate
	* newMBeanServerDelegate} or {@link
	* MBeanServerBuilder#newMBeanServer newMBeanServer} methods.
	*
	* @exception ClassCastException if the property
	* <code>javax.management.builder.initial</code> exists and can be
	* instantiated but is not assignment compatible with {@link
	* MBeanServerBuilder}.
	*/
	public static MBeanServer createMBeanServer() {
	return createMBeanServer(null);
	}

	/**
	* <p>Return a new object implementing the {@link MBeanServer}
	* interface with the specified default domain name. The given
	* domain name is used as the domain part in the ObjectName of
	* MBeans when the domain is specified by the user is null.</p>
	*
	* <p>The MBeanServer reference is internally kept. This will
	* allow <CODE>findMBeanServer</CODE> to return a reference to
	* this MBeanServer object.</p>
	*
	* @param domain the default domain name for the created
	* MBeanServer. This is the value that will be returned by {@link
	* MBeanServer#getDefaultDomain}.
	*
	* @return the newly created MBeanServer.
	*
	* @exception SecurityException if there is a SecurityManager and
	* the caller's permissions do not include or imply <code>{@link
	* MBeanServerPermission}("createMBeanServer")</code>.
	*
	* @exception JMRuntimeException if the property
	* <code>javax.management.builder.initial</code> exists but the
	* class it names cannot be instantiated through a public
	* no-argument constructor; or if the instantiated builder returns
	* null from its {@link MBeanServerBuilder#newMBeanServerDelegate
	* newMBeanServerDelegate} or {@link
	* MBeanServerBuilder#newMBeanServer newMBeanServer} methods.
	*
	* @exception ClassCastException if the property
	* <code>javax.management.builder.initial</code> exists and can be
	* instantiated but is not assignment compatible with {@link
	* MBeanServerBuilder}.
	*/
	public static MBeanServer createMBeanServer(String domain) {
	checkPermission("createMBeanServer");

	final MBeanServer mBeanServer = newMBeanServer(domain);
	addMBeanServer(mBeanServer);
	return mBeanServer;
	}

	/**
	* <p>Return a new object implementing the MBeanServer interface
	* with a standard default domain name, without keeping an
	* internal reference to this new object. The default domain name
	* is used as the domain part in the ObjectName of MBeans when the
	* domain is specified by the user is null.</p>
	*
	* <p>The standard default domain name is
	* <code>DefaultDomain</code>.</p>
	*
	* <p>No reference is kept. <CODE>findMBeanServer</CODE> will not
	* be able to return a reference to this MBeanServer object, but
	* the garbage collector will be able to remove the MBeanServer
	* object when it is no longer referenced.</p>
	*
	* <p>This method is equivalent to <code>newMBeanServer(null)</code>.</p>
	*
	* @return the newly created MBeanServer.
	*
	* @exception SecurityException if there is a SecurityManager and the
	* caller's permissions do not include or imply <code>{@link
	* MBeanServerPermission}("newMBeanServer")</code>.
	*
	* @exception JMRuntimeException if the property
	* <code>javax.management.builder.initial</code> exists but the
	* class it names cannot be instantiated through a public
	* no-argument constructor; or if the instantiated builder returns
	* null from its {@link MBeanServerBuilder#newMBeanServerDelegate
	* newMBeanServerDelegate} or {@link
	* MBeanServerBuilder#newMBeanServer newMBeanServer} methods.
	*
	* @exception ClassCastException if the property
	* <code>javax.management.builder.initial</code> exists and can be
	* instantiated but is not assignment compatible with {@link
	* MBeanServerBuilder}.
	*/
	public static MBeanServer newMBeanServer() {
	return newMBeanServer(null);
	}

	/**
	* <p>Return a new object implementing the MBeanServer interface
	* with the specified default domain name, without keeping an
	* internal reference to this new object. The given domain name
	* is used as the domain part in the ObjectName of MBeans when the
	* domain is specified by the user is null.</p>
	*
	* <p>No reference is kept. <CODE>findMBeanServer</CODE> will not
	* be able to return a reference to this MBeanServer object, but
	* the garbage collector will be able to remove the MBeanServer
	* object when it is no longer referenced.</p>
	*
	* @param domain the default domain name for the created
	* MBeanServer. This is the value that will be returned by {@link
	* MBeanServer#getDefaultDomain}.
	*
	* @return the newly created MBeanServer.
	*
	* @exception SecurityException if there is a SecurityManager and the
	* caller's permissions do not include or imply <code>{@link
	* MBeanServerPermission}("newMBeanServer")</code>.
	*
	* @exception JMRuntimeException if the property
	* <code>javax.management.builder.initial</code> exists but the
	* class it names cannot be instantiated through a public
	* no-argument constructor; or if the instantiated builder returns
	* null from its {@link MBeanServerBuilder#newMBeanServerDelegate
	* newMBeanServerDelegate} or {@link
	* MBeanServerBuilder#newMBeanServer newMBeanServer} methods.
	*
	* @exception ClassCastException if the property
	* <code>javax.management.builder.initial</code> exists and can be
	* instantiated but is not assignment compatible with {@link
	* MBeanServerBuilder}.
	*/
	public static MBeanServer newMBeanServer(String domain) {
	checkPermission("newMBeanServer");

	// Get the builder. Creates a new one if necessary.
	//
	final MBeanServerBuilder mbsBuilder = getNewMBeanServerBuilder();
	// Returned value cannot be null. NullPointerException if violated.

	synchronized(mbsBuilder) {
	final MBeanServerDelegate delegate =
	mbsBuilder.newMBeanServerDelegate();
	if (delegate == null) {
	final String msg =
	"MBeanServerBuilder.newMBeanServerDelegate() " +
	"returned null";
	throw new JMRuntimeException(msg);
	}
	final MBeanServer mbeanServer =
	mbsBuilder.newMBeanServer(domain,null,delegate);
	if (mbeanServer == null) {
	final String msg =
	"MBeanServerBuilder.newMBeanServer() returned null";
	throw new JMRuntimeException(msg);
	}
	return mbeanServer;
	}
	}

	/**
	* <p>Return a list of registered MBeanServer objects. A
	* registered MBeanServer object is one that was created by one of
	* the <code>createMBeanServer</code> methods and not subsequently
	* released with <code>releaseMBeanServer</code>.</p>
	*
	* @param agentId The agent identifier of the MBeanServer to
	* retrieve. If this parameter is null, all registered
	* MBeanServers in this JVM are returned. Otherwise, only
	* MBeanServers whose id is equal to <code>agentId</code> are
	* returned. The id of an MBeanServer is the
	* <code>MBeanServerId</code> attribute of its delegate MBean.
	*
	* @return A list of MBeanServer objects.
	*
	* @exception SecurityException if there is a SecurityManager and the
	* caller's permissions do not include or imply <code>{@link
	* MBeanServerPermission}("findMBeanServer")</code>.
	*/
	public synchronized static
	ArrayList<MBeanServer> findMBeanServer(String agentId) {

	checkPermission("findMBeanServer");

	if (agentId == null)
	return new ArrayList<MBeanServer>(mBeanServerList);

	ArrayList<MBeanServer> result = new ArrayList<MBeanServer>();
	for (MBeanServer mbs : mBeanServerList) {
	String name = mBeanServerId(mbs);
	if (agentId.equals(name))
	result.add(mbs);
	}
	return result;
	}

	/**
	* Return the ClassLoaderRepository used by the given MBeanServer.
	* This method is equivalent to {@link
	* MBeanServer#getClassLoaderRepository() server.getClassLoaderRepository()}.
	* @param server The MBeanServer under examination. Since JMX 1.2,
	* if <code>server</code> is <code>null</code>, the result is a
	* {@link NullPointerException}. This behavior differs from what
	* was implemented in JMX 1.1 - where the possibility to use
	* <code>null</code> was deprecated.
	* @return The Class Loader Repository used by the given MBeanServer.
	* @exception SecurityException if there is a SecurityManager and
	* the caller's permissions do not include or imply <code>{@link
	* MBeanPermission}("getClassLoaderRepository")</code>.
	*
	* @exception NullPointerException if <code>server</code> is null.
	*
	**/
	public static ClassLoaderRepository getClassLoaderRepository(
	MBeanServer server) {
	return server.getClassLoaderRepository();
	}

	private static String mBeanServerId(MBeanServer mbs) {
	try {
	return (String) mbs.getAttribute(MBeanServerDelegate.DELEGATE_NAME,
	"MBeanServerId");
	} catch (JMException e) {
	JmxProperties.MISC_LOGGER.finest(
	"Ignoring exception while getting MBeanServerId: "+e);
	return null;
	}
	}

	private static void checkPermission(String action)
	throws SecurityException {
	SecurityManager sm = System.getSecurityManager();
	if (sm != null) {
	Permission perm = new MBeanServerPermission(action);
	sm.checkPermission(perm);
	}
	}

	private static synchronized void addMBeanServer(MBeanServer mbs) {
	mBeanServerList.add(mbs);
	}

	private static synchronized void removeMBeanServer(MBeanServer mbs) {
	boolean removed = mBeanServerList.remove(mbs);
	if (!removed) {
	MBEANSERVER_LOGGER.logp(Level.FINER,
	MBeanServerFactory.class.getName(),
	"removeMBeanServer(MBeanServer)",
	"MBeanServer was not in list!");
	throw new IllegalArgumentException("MBeanServer was not in list!");
	}
	}

	private static final ArrayList<MBeanServer> mBeanServerList =
	new ArrayList<MBeanServer>();

	/**
	* Load the builder class through the context class loader.
	* @param builderClassName The name of the builder class.
	**/
	private static Class<?> loadBuilderClass(String builderClassName)
	throws ClassNotFoundException {
	final ClassLoader loader =
	Thread.currentThread().getContextClassLoader();

	if (loader != null) {
	// Try with context class loader
	return loader.loadClass(builderClassName);
	}

	// No context class loader? Try with Class.forName()
	return ReflectUtil.forName(builderClassName);
	}

	/**
	* Creates the initial builder according to the
	* javax.management.builder.initial System property - if specified.
	* If any checked exception needs to be thrown, it is embedded in
	* a JMRuntimeException.
	**/
	private static MBeanServerBuilder newBuilder(Class<?> builderClass) {
	try {
	final Object abuilder = builderClass.newInstance();
	return (MBeanServerBuilder)abuilder;
	} catch (RuntimeException x) {
	throw x;
	} catch (Exception x) {
	final String msg =
	"Failed to instantiate a MBeanServerBuilder from " +
	builderClass + ": " + x;
	throw new JMRuntimeException(msg, x);
	}
	}

	/**
	* Instantiate a new builder according to the
	* javax.management.builder.initial System property - if needed.
	**/
	private static synchronized void checkMBeanServerBuilder() {
	try {
	GetPropertyAction act =
	new GetPropertyAction(JMX_INITIAL_BUILDER);
	String builderClassName = AccessController.doPrivileged(act);

	try {
	final Class<?> newBuilderClass;
	if (builderClassName == null \|\| builderClassName.length() == 0)
	newBuilderClass = MBeanServerBuilder.class;
	else
	newBuilderClass = loadBuilderClass(builderClassName);

	// Check whether a new builder needs to be created
	if (builder != null) {
	final Class<?> builderClass = builder.getClass();
	if (newBuilderClass == builderClass)
	return; // no need to create a new builder...
	}

	// Create a new builder
	builder = newBuilder(newBuilderClass);
	} catch (ClassNotFoundException x) {
	final String msg =
	"Failed to load MBeanServerBuilder class " +
	builderClassName + ": " + x;
	throw new JMRuntimeException(msg, x);
	}
	} catch (RuntimeException x) {
	if (MBEANSERVER_LOGGER.isLoggable(Level.FINEST)) {
	StringBuilder strb = new StringBuilder()
	.append("Failed to instantiate MBeanServerBuilder: ").append(x)
	.append("\n\t\tCheck the value of the ")
	.append(JMX_INITIAL_BUILDER).append(" property.");
	MBEANSERVER_LOGGER.logp(Level.FINEST,
	MBeanServerFactory.class.getName(),
	"checkMBeanServerBuilder",
	strb.toString());
	}
	throw x;
	}
	}

	/**
	* Get the current {@link javax.management.MBeanServerBuilder},
	* as specified by the current value of the
	* javax.management.builder.initial property.
	*
	* This method consults the property and instantiates a new builder
	* if needed.
	*
	* @return the new current {@link javax.management.MBeanServerBuilder}.
	*
	* @exception SecurityException if there is a SecurityManager and
	* the caller's permissions do not make it possible to instantiate
	* a new builder.
	* @exception JMRuntimeException if the builder instantiation
	* fails with a checked exception -
	* {@link java.lang.ClassNotFoundException} etc...
	*
	**/
	private static synchronized MBeanServerBuilder getNewMBeanServerBuilder() {
	checkMBeanServerBuilder();
	return builder;
	}

	}

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