Java tutorial
/* * Copyright 2002-2017 the original author or authors. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * https://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package org.springframework.jmx.support; import javax.management.MBeanServer; import javax.management.MBeanServerFactory; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.springframework.beans.factory.DisposableBean; import org.springframework.beans.factory.FactoryBean; import org.springframework.beans.factory.InitializingBean; import org.springframework.jmx.MBeanServerNotFoundException; import org.springframework.lang.Nullable; /** * {@link FactoryBean} that obtains an {@link javax.management.MBeanServer} reference * through the standard JMX 1.2 {@link javax.management.MBeanServerFactory} * API (which is available on JDK 1.5 or as part of a JMX 1.2 provider). * Exposes the {@code MBeanServer} for bean references. * * <p>By default, {@code MBeanServerFactoryBean} will always create * a new {@code MBeanServer} even if one is already running. To have * the {@code MBeanServerFactoryBean} attempt to locate a running * {@code MBeanServer} first, set the value of the * "locateExistingServerIfPossible" property to "true". * * @author Rob Harrop * @author Juergen Hoeller * @since 1.2 * @see #setLocateExistingServerIfPossible * @see #locateMBeanServer * @see javax.management.MBeanServer * @see javax.management.MBeanServerFactory#findMBeanServer * @see javax.management.MBeanServerFactory#createMBeanServer * @see javax.management.MBeanServerFactory#newMBeanServer * @see MBeanServerConnectionFactoryBean * @see ConnectorServerFactoryBean */ public class MBeanServerFactoryBean implements FactoryBean<MBeanServer>, InitializingBean, DisposableBean { protected final Log logger = LogFactory.getLog(getClass()); private boolean locateExistingServerIfPossible = false; @Nullable private String agentId; @Nullable private String defaultDomain; private boolean registerWithFactory = true; @Nullable private MBeanServer server; private boolean newlyRegistered = false; /** * Set whether or not the {@code MBeanServerFactoryBean} should attempt * to locate a running {@code MBeanServer} before creating one. * <p>Default is {@code false}. */ public void setLocateExistingServerIfPossible(boolean locateExistingServerIfPossible) { this.locateExistingServerIfPossible = locateExistingServerIfPossible; } /** * Set the agent id of the {@code MBeanServer} to locate. * <p>Default is none. If specified, this will result in an * automatic attempt being made to locate the attendant MBeanServer, * and (importantly) if said MBeanServer cannot be located no * attempt will be made to create a new MBeanServer (and an * MBeanServerNotFoundException will be thrown at resolution time). * <p>Specifying the empty String indicates the platform MBeanServer. * @see javax.management.MBeanServerFactory#findMBeanServer(String) */ public void setAgentId(String agentId) { this.agentId = agentId; } /** * Set the default domain to be used by the {@code MBeanServer}, * to be passed to {@code MBeanServerFactory.createMBeanServer()} * or {@code MBeanServerFactory.findMBeanServer()}. * <p>Default is none. * @see javax.management.MBeanServerFactory#createMBeanServer(String) * @see javax.management.MBeanServerFactory#findMBeanServer(String) */ public void setDefaultDomain(String defaultDomain) { this.defaultDomain = defaultDomain; } /** * Set whether to register the {@code MBeanServer} with the * {@code MBeanServerFactory}, making it available through * {@code MBeanServerFactory.findMBeanServer()}. * @see javax.management.MBeanServerFactory#createMBeanServer * @see javax.management.MBeanServerFactory#findMBeanServer */ public void setRegisterWithFactory(boolean registerWithFactory) { this.registerWithFactory = registerWithFactory; } /** * Creates the {@code MBeanServer} instance. */ @Override public void afterPropertiesSet() throws MBeanServerNotFoundException { // Try to locate existing MBeanServer, if desired. if (this.locateExistingServerIfPossible || this.agentId != null) { try { this.server = locateMBeanServer(this.agentId); } catch (MBeanServerNotFoundException ex) { // If agentId was specified, we were only supposed to locate that // specific MBeanServer; so let's bail if we can't find it. if (this.agentId != null) { throw ex; } logger.debug("No existing MBeanServer found - creating new one"); } } // Create a new MBeanServer and register it, if desired. if (this.server == null) { this.server = createMBeanServer(this.defaultDomain, this.registerWithFactory); this.newlyRegistered = this.registerWithFactory; } } /** * Attempt to locate an existing {@code MBeanServer}. * Called if {@code locateExistingServerIfPossible} is set to {@code true}. * <p>The default implementation attempts to find an {@code MBeanServer} using * a standard lookup. Subclasses may override to add additional location logic. * @param agentId the agent identifier of the MBeanServer to retrieve. * If this parameter is {@code null}, all registered MBeanServers are * considered. * @return the {@code MBeanServer} if found * @throws org.springframework.jmx.MBeanServerNotFoundException * if no {@code MBeanServer} could be found * @see #setLocateExistingServerIfPossible * @see JmxUtils#locateMBeanServer(String) * @see javax.management.MBeanServerFactory#findMBeanServer(String) */ protected MBeanServer locateMBeanServer(@Nullable String agentId) throws MBeanServerNotFoundException { return JmxUtils.locateMBeanServer(agentId); } /** * Create a new {@code MBeanServer} instance and register it with the * {@code MBeanServerFactory}, if desired. * @param defaultDomain the default domain, or {@code null} if none * @param registerWithFactory whether to register the {@code MBeanServer} * with the {@code MBeanServerFactory} * @see javax.management.MBeanServerFactory#createMBeanServer * @see javax.management.MBeanServerFactory#newMBeanServer */ protected MBeanServer createMBeanServer(@Nullable String defaultDomain, boolean registerWithFactory) { if (registerWithFactory) { return MBeanServerFactory.createMBeanServer(defaultDomain); } else { return MBeanServerFactory.newMBeanServer(defaultDomain); } } @Override @Nullable public MBeanServer getObject() { return this.server; } @Override public Class<? extends MBeanServer> getObjectType() { return (this.server != null ? this.server.getClass() : MBeanServer.class); } @Override public boolean isSingleton() { return true; } /** * Unregisters the {@code MBeanServer} instance, if necessary. */ @Override public void destroy() { if (this.newlyRegistered) { MBeanServerFactory.releaseMBeanServer(this.server); } } }