/*
 * Copyright 2002-2019 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 java.io.IOException;
import java.util.HashMap;
import java.util.Map;
import java.util.Properties;

import javax.management.JMException;
import javax.management.MBeanServer;
import javax.management.MalformedObjectNameException;
import javax.management.ObjectName;
import javax.management.remote.JMXConnectorServer;
import javax.management.remote.JMXConnectorServerFactory;
import javax.management.remote.JMXServiceURL;
import javax.management.remote.MBeanServerForwarder;

import org.springframework.beans.factory.DisposableBean;
import org.springframework.beans.factory.FactoryBean;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.jmx.JmxException;
import org.springframework.lang.Nullable;
import org.springframework.util.CollectionUtils;

/**
 * {@link FactoryBean} that creates a JSR-160 {@link JMXConnectorServer},
 * optionally registers it with the {@link MBeanServer}, and then starts it.
 *
 * <p>The {@code JMXConnectorServer} can be started in a separate thread by setting the
 * {@code threaded} property to {@code true}. You can configure this thread to be a
 * daemon thread by setting the {@code daemon} property to {@code true}.
 *
 * <p>The {@code JMXConnectorServer} is correctly shut down when an instance of this
 * class is destroyed on shutdown of the containing {@code ApplicationContext}.
 *
 * @author Rob Harrop
 * @author Juergen Hoeller
 * @since 1.2
 * @see JMXConnectorServer
 * @see MBeanServer
 */
public class ConnectorServerFactoryBean extends MBeanRegistrationSupport
                implements FactoryBean<JMXConnectorServer>, InitializingBean, DisposableBean {

        /** The default service URL. */
        public static final String DEFAULT_SERVICE_URL = "service:jmx:jmxmp://localhost:9875";


        private String serviceUrl = DEFAULT_SERVICE_URL;

        private Map<String, Object> environment = new HashMap<>();

        @Nullable
        private MBeanServerForwarder forwarder;

        @Nullable
        private ObjectName objectName;

        private boolean threaded = false;

        private boolean daemon = false;

        @Nullable
        private JMXConnectorServer connectorServer;


        /**
         * Set the service URL for the {@code JMXConnectorServer}.
         */
        public void setServiceUrl(String serviceUrl) {
                this.serviceUrl = serviceUrl;
        }

        /**
         * Set the environment properties used to construct the {@code JMXConnectorServer}
         * as {@code java.util.Properties} (String key/value pairs).
         */
        public void setEnvironment(@Nullable Properties environment) {
                CollectionUtils.mergePropertiesIntoMap(environment, this.environment);
        }

        /**
         * Set the environment properties used to construct the {@code JMXConnector}
         * as a {@code Map} of String keys and arbitrary Object values.
         */
        public void setEnvironmentMap(@Nullable Map<String, ?> environment) {
                if (environment != null) {
                        this.environment.putAll(environment);
                }
        }

        /**
         * Set an MBeanServerForwarder to be applied to the {@code JMXConnectorServer}.
         */
        public void setForwarder(MBeanServerForwarder forwarder) {
                this.forwarder = forwarder;
        }

        /**
         * Set the {@code ObjectName} used to register the {@code JMXConnectorServer}
         * itself with the {@code MBeanServer}, as {@code ObjectName} instance
         * or as {@code String}.
         * @throws MalformedObjectNameException if the {@code ObjectName} is malformed
         */
        public void setObjectName(Object objectName) throws MalformedObjectNameException {
                this.objectName = ObjectNameManager.getInstance(objectName);
        }

        /**
         * Set whether the {@code JMXConnectorServer} should be started in a separate thread.
         */
        public void setThreaded(boolean threaded) {
                this.threaded = threaded;
        }

        /**
         * Set whether any threads started for the {@code JMXConnectorServer} should be
         * started as daemon threads.
         */
        public void setDaemon(boolean daemon) {
                this.daemon = daemon;
        }


        /**
         * Start the connector server. If the {@code threaded} flag is set to {@code true},
         * the {@code JMXConnectorServer} will be started in a separate thread.
         * If the {@code daemon} flag is set to {@code true}, that thread will be
         * started as a daemon thread.
         * @throws JMException if a problem occurred when registering the connector server
         * with the {@code MBeanServer}
         * @throws IOException if there is a problem starting the connector server
         */
        @Override
        public void afterPropertiesSet() throws JMException, IOException {
                if (this.server == null) {
                        this.server = JmxUtils.locateMBeanServer();
                }

                // Create the JMX service URL.
                JMXServiceURL url = new JMXServiceURL(this.serviceUrl);

                // Create the connector server now.
                this.connectorServer = JMXConnectorServerFactory.newJMXConnectorServer(url, this.environment, this.server);

                // Set the given MBeanServerForwarder, if any.
                if (this.forwarder != null) {
                        this.connectorServer.setMBeanServerForwarder(this.forwarder);
                }

                // Do we want to register the connector with the MBean server?
                if (this.objectName != null) {
                        doRegister(this.connectorServer, this.objectName);
                }

                try {
                        if (this.threaded) {
                                // Start the connector server asynchronously (in a separate thread).
                                final JMXConnectorServer serverToStart = this.connectorServer;
                                Thread connectorThread = new Thread() {
                                        @Override
                                        public void run() {
                                                try {
                                                        serverToStart.start();
                                                }
                                                catch (IOException ex) {
                                                        throw new JmxException("Could not start JMX connector server after delay", ex);
                                                }
                                        }
                                };

                                connectorThread.setName("JMX Connector Thread [" + this.serviceUrl + "]");
                                connectorThread.setDaemon(this.daemon);
                                connectorThread.start();
                        }
                        else {
                                // Start the connector server in the same thread.
                                this.connectorServer.start();
                        }

                        if (logger.isInfoEnabled()) {
                                logger.info("JMX connector server started: " + this.connectorServer);
                        }
                }

                catch (IOException ex) {
                        // Unregister the connector server if startup failed.
                        unregisterBeans();
                        throw ex;
                }
        }


        @Override
        @Nullable
        public JMXConnectorServer getObject() {
                return this.connectorServer;
        }

        @Override
        public Class<? extends JMXConnectorServer> getObjectType() {
                return (this.connectorServer != null ? this.connectorServer.getClass() : JMXConnectorServer.class);
        }

        @Override
        public boolean isSingleton() {
                return true;
        }


        /**
         * Stop the {@code JMXConnectorServer} managed by an instance of this class.
         * Automatically called on {@code ApplicationContext} shutdown.
         * @throws IOException if there is an error stopping the connector server
         */
        @Override
        public void destroy() throws IOException {
                try {
                        if (this.connectorServer != null) {
                                if (logger.isInfoEnabled()) {
                                        logger.info("Stopping JMX connector server: " + this.connectorServer);
                                }
                                this.connectorServer.stop();
                        }
                }
                finally {
                        unregisterBeans();
                }
        }

}