Java tutorial
/* * Copyright (c) 2003, 2018, 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.remote; import com.sun.jmx.remote.util.ClassLogger; import com.sun.jmx.remote.util.EnvHelp; import java.io.IOException; import java.io.UncheckedIOException; import java.net.MalformedURLException; import java.util.Collections; import java.util.HashMap; import java.util.Map; import java.util.ServiceLoader.Provider; import java.util.function.Predicate; import javax.management.MBeanServer; import javax.management.remote.JMXConnectorFactory.ConnectorFactory; /** * <p>Factory to create JMX API connector servers. There * are no instances of this class.</p> * * <p>Each connector server is created by an instance of {@link * JMXConnectorServerProvider}. This instance is found as follows. Suppose * the given {@link JMXServiceURL} looks like * <code>"service:jmx:<em>protocol</em>:<em>remainder</em>"</code>. * Then the factory will attempt to find the appropriate {@link * JMXConnectorServerProvider} for <code><em>protocol</em></code>. Each * occurrence of the character <code>+</code> or <code>-</code> in * <code><em>protocol</em></code> is replaced by <code>.</code> or * <code>_</code>, respectively.</p> * * <p>A <em>provider package list</em> is searched for as follows:</p> * * <ol> * * <li>If the <code>environment</code> parameter to {@link * #newJMXConnectorServer(JMXServiceURL,Map,MBeanServer) * newJMXConnectorServer} contains the key * <code>jmx.remote.protocol.provider.pkgs</code> then the associated * value is the provider package list. * * <li>Otherwise, if the system property * <code>jmx.remote.protocol.provider.pkgs</code> exists, then its value * is the provider package list. * * <li>Otherwise, there is no provider package list. * * </ol> * * <p>The provider package list is a string that is interpreted as a * list of non-empty Java package names separated by vertical bars * (<code>|</code>). If the string is empty, then so is the provider * package list. If the provider package list is not a String, or if * it contains an element that is an empty string, a {@link * JMXProviderException} is thrown.</p> * * <p>If the provider package list exists and is not empty, then for * each element <code><em>pkg</em></code> of the list, the factory * will attempt to load the class * * <blockquote> * <code><em>pkg</em>.<em>protocol</em>.ServerProvider</code> * </blockquote> * <p>If the <code>environment</code> parameter to {@link * #newJMXConnectorServer(JMXServiceURL, Map, MBeanServer) * newJMXConnectorServer} contains the key * <code>jmx.remote.protocol.provider.class.loader</code> then the * associated value is the class loader to use to load the provider. * If the associated value is not an instance of {@link * java.lang.ClassLoader}, an {@link * java.lang.IllegalArgumentException} is thrown.</p> * * <p>If the <code>jmx.remote.protocol.provider.class.loader</code> * key is not present in the <code>environment</code> parameter, the * calling thread's context class loader is used.</p> * * <p>If the attempt to load this class produces a {@link * ClassNotFoundException}, the search for a handler continues with * the next element of the list.</p> * * <p>Otherwise, a problem with the provider found is signalled by a * {@link JMXProviderException} whose {@link * JMXProviderException#getCause() <em>cause</em>} indicates the * underlying exception, as follows:</p> * * <ul> * * <li>if the attempt to load the class produces an exception other * than <code>ClassNotFoundException</code>, that is the * <em>cause</em>; * * <li>if {@link Class#newInstance()} for the class produces an * exception, that is the <em>cause</em>. * * </ul> * * <p>If no provider is found by the above steps, including the * default case where there is no provider package list, then the * implementation will use its own provider for * <code><em>protocol</em></code>, or it will throw a * <code>MalformedURLException</code> if there is none. An * implementation may choose to find providers by other means. For * example, it may support <a * href="{@docRoot}/java.base/java/util/ServiceLoader.html#developing-service-providers">service providers</a>, * where the service interface is <code>JMXConnectorServerProvider</code>.</p> * * <p>Every implementation must support the RMI connector protocol with * the default RMI transport, specified with string <code>rmi</code>. * </p> * * <p>Once a provider is found, the result of the * <code>newJMXConnectorServer</code> method is the result of calling * {@link * JMXConnectorServerProvider#newJMXConnectorServer(JMXServiceURL, * Map, MBeanServer) newJMXConnectorServer} on the provider.</p> * * <p>The <code>Map</code> parameter passed to the * <code>JMXConnectorServerProvider</code> is a new read-only * <code>Map</code> that contains all the entries that were in the * <code>environment</code> parameter to {@link * #newJMXConnectorServer(JMXServiceURL,Map,MBeanServer) * JMXConnectorServerFactory.newJMXConnectorServer}, if there was one. * Additionally, if the * <code>jmx.remote.protocol.provider.class.loader</code> key is not * present in the <code>environment</code> parameter, it is added to * the new read-only <code>Map</code>. The associated value is the * calling thread's context class loader.</p> * * @since 1.5 */ public class JMXConnectorServerFactory { /** * <p>Name of the attribute that specifies the default class * loader. This class loader is used to deserialize objects in * requests received from the client, possibly after consulting an * MBean-specific class loader. The value associated with this * attribute is an instance of {@link ClassLoader}.</p> */ public static final String DEFAULT_CLASS_LOADER = JMXConnectorFactory.DEFAULT_CLASS_LOADER; /** * <p>Name of the attribute that specifies the default class * loader MBean name. This class loader is used to deserialize objects in * requests received from the client, possibly after consulting an * MBean-specific class loader. The value associated with this * attribute is an instance of {@link javax.management.ObjectName * ObjectName}.</p> */ public static final String DEFAULT_CLASS_LOADER_NAME = "jmx.remote.default.class.loader.name"; /** * <p>Name of the attribute that specifies the provider packages * that are consulted when looking for the handler for a protocol. * The value associated with this attribute is a string with * package names separated by vertical bars (<code>|</code>).</p> */ public static final String PROTOCOL_PROVIDER_PACKAGES = "jmx.remote.protocol.provider.pkgs"; /** * <p>Name of the attribute that specifies the class * loader for loading protocol providers. * The value associated with this attribute is an instance * of {@link ClassLoader}.</p> */ public static final String PROTOCOL_PROVIDER_CLASS_LOADER = "jmx.remote.protocol.provider.class.loader"; private static final String PROTOCOL_PROVIDER_DEFAULT_PACKAGE = "com.sun.jmx.remote.protocol"; private static final ClassLogger logger = new ClassLogger("javax.management.remote.misc", "JMXConnectorServerFactory"); /** There are no instances of this class. */ private JMXConnectorServerFactory() { } private static JMXConnectorServer getConnectorServerAsService(ClassLoader loader, JMXServiceURL url, Map<String, ?> map, MBeanServer mbs, Predicate<Provider<?>> filter) throws IOException { final ConnectorFactory<JMXConnectorServerProvider, JMXConnectorServer> factory = (p) -> p .newJMXConnectorServer(url, map, mbs); return JMXConnectorFactory.getConnectorAsService(JMXConnectorServerProvider.class, loader, url, filter, factory); } /** * <p>Creates a connector server at the given address. The * resultant server is not started until its {@link * JMXConnectorServer#start() start} method is called.</p> * * @param serviceURL the address of the new connector server. The * actual address of the new connector server, as returned by its * {@link JMXConnectorServer#getAddress() getAddress} method, will * not necessarily be exactly the same. For example, it might * include a port number if the original address did not. * * @param environment a set of attributes to control the new * connector server's behavior. This parameter can be null. * Keys in this map must be Strings. The appropriate type of each * associated value depends on the attribute. The contents of * <code>environment</code> are not changed by this call. * * @param mbeanServer the MBean server that this connector server * is attached to. Null if this connector server will be attached * to an MBean server by being registered in it. * * @return a <code>JMXConnectorServer</code> representing the new * connector server. Each successful call to this method produces * a different object. * * @exception NullPointerException if <code>serviceURL</code> is null. * * @exception IOException if the connector server cannot be made * because of a communication problem. * * @exception MalformedURLException if there is no provider for the * protocol in <code>serviceURL</code>. * * @exception JMXProviderException if there is a provider for the * protocol in <code>serviceURL</code> but it cannot be used for * some reason. */ public static JMXConnectorServer newJMXConnectorServer(JMXServiceURL serviceURL, Map<String, ?> environment, MBeanServer mbeanServer) throws IOException { Map<String, Object> envcopy; if (environment == null) envcopy = new HashMap<String, Object>(); else { EnvHelp.checkAttributes(environment); envcopy = new HashMap<String, Object>(environment); } final Class<JMXConnectorServerProvider> targetInterface = JMXConnectorServerProvider.class; final ClassLoader loader = JMXConnectorFactory.resolveClassLoader(envcopy); final String protocol = serviceURL.getProtocol(); final String providerClassName = "ServerProvider"; JMXConnectorServerProvider provider = JMXConnectorFactory.getProvider(serviceURL, envcopy, providerClassName, targetInterface, loader); IOException exception = null; JMXConnectorServer connection = null; if (provider == null) { Predicate<Provider<?>> systemProvider = JMXConnectorFactory::isSystemProvider; // Loader is null when context class loader is set to null // and no loader has been provided in map. // com.sun.jmx.remote.util.Service class extracted from j2se // provider search algorithm doesn't handle well null classloader. if (loader != null) { try { connection = getConnectorServerAsService(loader, serviceURL, envcopy, mbeanServer, systemProvider.negate()); if (connection != null) return connection; } catch (JMXProviderException e) { throw e; } catch (IOException e) { exception = e; } } connection = getConnectorServerAsService(JMXConnectorFactory.class.getClassLoader(), serviceURL, Collections.unmodifiableMap(envcopy), mbeanServer, systemProvider); if (connection != null) return connection; } if (provider == null) { MalformedURLException e = new MalformedURLException("Unsupported protocol: " + protocol); if (exception == null) { throw e; } else { throw EnvHelp.initCause(e, exception); } } envcopy = Collections.unmodifiableMap(envcopy); return provider.newJMXConnectorServer(serviceURL, envcopy, mbeanServer); } }