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MBeanServerFactory.javaAPI DocJava SE 5 API21349Fri Aug 26 14:57:32 BST 2005javax.management

MBeanServerFactory

public class MBeanServerFactory extends Object

Provides MBean server references. There are no instances of this class.

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 javax.management.builder.initial system property. The specified class must be a public subclass of {@link javax.management.MBeanServerBuilder}, and must have a public empty constructor.

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.

The javax.management.builder.initial 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.

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 javax.management.builder.initial system property is reset to valid value.

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.

since
1.5

Fields Summary
private static MBeanServerBuilder
builder
The builder that will be used to construct MBeanServers.
private static final ObjectName
delegateName
private static final ArrayList
mBeanServerList
Constructors Summary
private MBeanServerFactory()

	
    
Methods Summary
private static synchronized voidaddMBeanServer(javax.management.MBeanServer mbs)

        mBeanServerList.add(mbs);
    
private static synchronized voidcheckMBeanServerBuilder()
Instantiate a new builder according to the javax.management.builder.initial System property - if needed.

	try {
	    PrivilegedAction act =
		new GetPropertyAction(JmxProperties.JMX_INITIAL_BUILDER);
	    String builderClassName = (String)
		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) {
	    debug("checkMBeanServerBuilder",
		  "Failed to instantiate MBeanServerBuilder: " + x +
		  "\n\t\tCheck the value of the " + 
		  JmxProperties.JMX_INITIAL_BUILDER + " property." );
	    throw x;
	}
    
private static voidcheckPermission(java.lang.String action)

	SecurityManager sm = System.getSecurityManager();
	if (sm != null) {
	    Permission perm = new MBeanServerPermission(action);
	    sm.checkPermission(perm);
	}
    
public static javax.management.MBeanServercreateMBeanServer()

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.

The standard default domain name is DefaultDomain.

The MBeanServer reference is internally kept. This will allow findMBeanServer to return a reference to this MBeanServer object.

This method is equivalent to createMBeanServer(null).

return
the newly created MBeanServer.
exception
SecurityException if there is a SecurityManager and the caller's permissions do not include or imply {@link MBeanServerPermission}("createMBeanServer").
exception
JMRuntimeException if the property javax.management.builder.initial 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 javax.management.builder.initial exists and can be instantiated but is not assignment compatible with {@link MBeanServerBuilder}.

	return createMBeanServer(null);
    
public static javax.management.MBeanServercreateMBeanServer(java.lang.String domain)

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.

The MBeanServer reference is internally kept. This will allow findMBeanServer to return a reference to this MBeanServer object.

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 {@link MBeanServerPermission}("createMBeanServer").
exception
JMRuntimeException if the property javax.management.builder.initial 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 javax.management.builder.initial exists and can be instantiated but is not assignment compatible with {@link MBeanServerBuilder}.

	checkPermission("createMBeanServer");

	final MBeanServer mBeanServer = newMBeanServer(domain);
	addMBeanServer(mBeanServer);
	return mBeanServer;
    
private static voiddebug(java.lang.String method, java.lang.String message)
Private Stuff

	if (Trace.isSelected(Trace.LEVEL_DEBUG, Trace.INFO_MBEANSERVER)) {
	    Trace.send(Trace.LEVEL_DEBUG, Trace.INFO_MBEANSERVER,
		       MBeanServerFactory.class.getName(), method, message);
	}
    
private static voiderror(java.lang.String method, java.lang.String message)
Private Stuff

	if (Trace.isSelected(Trace.LEVEL_ERROR, Trace.INFO_MBEANSERVER)) {
	    Trace.send(Trace.LEVEL_ERROR, Trace.INFO_MBEANSERVER,
		       MBeanServerFactory.class.getName(), method, message);
	}
    
public static synchronized java.util.ArrayListfindMBeanServer(java.lang.String agentId)

Return a list of registered MBeanServer objects. A registered MBeanServer object is one that was created by one of the createMBeanServer methods and not subsequently released with releaseMBeanServer.

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 agentId are returned. The id of an MBeanServer is the MBeanServerId 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 {@link MBeanServerPermission}("findMBeanServer").

	checkPermission("findMBeanServer");

	if (agentId == null)
	    return (ArrayList) mBeanServerList.clone();

	ArrayList result = new ArrayList();
	for (Iterator i = mBeanServerList.iterator(); i.hasNext(); ) {
	    MBeanServer mbs = (MBeanServer) i.next();
	    String name = mBeanServerName(mbs);
	    if (agentId.equals(name))
		result.add(mbs);
	}
	return result;
    
public static javax.management.loading.ClassLoaderRepositorygetClassLoaderRepository(javax.management.MBeanServer server)
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 server is null, the result is a {@link NullPointerException}. This behavior differs from what was implemented in JMX 1.1 - where the possibility to use null 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 {@link MBeanPermission}("getClassLoaderRepository").
exception
NullPointerException if server is null.
since.unbundled
JMX 1.1

	return server.getClassLoaderRepository(); 
    
private static synchronized javax.management.MBeanServerBuildergetNewMBeanServerBuilder()
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...
since.unbundled
JMX 1.2

	checkMBeanServerBuilder();
	return builder;
    
private static java.lang.ClassloadBuilderClass(java.lang.String builderClassName)
Load the builder class through the context class loader.

param
builderClassName The name of the builder class.


                          
         
	      
	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 Class.forName(builderClassName);  
    
private static java.lang.StringmBeanServerName(javax.management.MBeanServer mbs)

	ObjectName name;
	try {
	    name = new ObjectName(ServiceName.DELEGATE);
	} catch (JMException e) {
	    /* This can only happen if ServiceName.DELEGATE is an invalid
	       ObjectName, which means serious brokenness!  */
	    name = null;
	    trace("<clinit>",
		  "internal error creating delegate ObjectName: " + e);
	}
	delegateName = name;
    
	try {
	    return (String) mbs.getAttribute(delegateName, "MBeanServerId");
	} catch (JMException e) {
	    return null;
	}
    
private static javax.management.MBeanServerBuildernewBuilder(java.lang.Class builderClass)
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.

	try {
	    final Object builder = builderClass.newInstance();
	    return (MBeanServerBuilder)builder;
	} catch (RuntimeException x) {
	    throw x;
	} catch (Exception x) {
	    final String msg =
               "Failed to instantiate a MBeanServerBuilder from " +
	       builderClass + ": " + x;
	    throw new JMRuntimeException(msg, x);
	}
    
public static javax.management.MBeanServernewMBeanServer()

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.

The standard default domain name is DefaultDomain.

No reference is kept. findMBeanServer 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.

This method is equivalent to newMBeanServer(null).

return
the newly created MBeanServer.
exception
SecurityException if there is a SecurityManager and the caller's permissions do not include or imply {@link MBeanServerPermission}("newMBeanServer").
exception
JMRuntimeException if the property javax.management.builder.initial 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 javax.management.builder.initial exists and can be instantiated but is not assignment compatible with {@link MBeanServerBuilder}.

	return newMBeanServer(null);
    
public static javax.management.MBeanServernewMBeanServer(java.lang.String domain)

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.

No reference is kept. findMBeanServer 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.

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 {@link MBeanServerPermission}("newMBeanServer").
exception
JMRuntimeException if the property javax.management.builder.initial 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 javax.management.builder.initial exists and can be instantiated but is not assignment compatible with {@link MBeanServerBuilder}.

	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;
	}
    
public static voidreleaseMBeanServer(javax.management.MBeanServer mbeanServer)
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 mbeanServer was not generated by one of the createMBeanServer methods, or if releaseMBeanServer was already called on it.
exception
SecurityException if there is a SecurityManager and the caller's permissions do not include or imply {@link MBeanServerPermission}("releaseMBeanServer").


                                                                 
    // public static synchronized void 
    //    setMBeanServerBuilder(MBeanServerBuilder builder) {
    //    checkPermission("setMBeanServerBuilder");
    //    MBeanServerFactory.builder = builder;
    // }
    
                                         
    // public static synchronized MBeanServerBuilder getMBeanServerBuilder() {
    //     checkPermission("getMBeanServerBuilder");
    //     return builder;
    // }

                                                                          
         
	checkPermission("releaseMBeanServer");

	removeMBeanServer(mbeanServer);
    
private static synchronized voidremoveMBeanServer(javax.management.MBeanServer mbs)

	boolean removed = mBeanServerList.remove(mbs);
	if (!removed) {
	    trace("removeMBeanServer", "MBeanServer was not in list!");
	    throw new IllegalArgumentException("MBeanServer was not in list!");
	}
    
private static voidtrace(java.lang.String method, java.lang.String message)
Private Stuff

	if (Trace.isSelected(Trace.LEVEL_TRACE, Trace.INFO_MBEANSERVER)) {
	    Trace.send(Trace.LEVEL_TRACE, Trace.INFO_MBEANSERVER,
		       MBeanServerFactory.class.getName(), method, message);
	}