/*
 * Copyright 2002-2018 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.access;

import java.io.IOException;
import java.net.MalformedURLException;
import java.util.Arrays;
import java.util.Map;

import javax.management.MBeanServerConnection;
import javax.management.ObjectName;
import javax.management.remote.JMXServiceURL;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import org.springframework.beans.factory.DisposableBean;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.jmx.JmxException;
import org.springframework.jmx.MBeanServerNotFoundException;
import org.springframework.jmx.support.NotificationListenerHolder;
import org.springframework.lang.Nullable;
import org.springframework.util.CollectionUtils;

Registrar object that associates a specific NotificationListener with one or more MBeans in an MBeanServer (typically via a MBeanServerConnection). 
Author:
Juergen Hoeller
See Also:
setServer
NotificationListenerHolder.setMappedObjectNames
NotificationListenerHolder.setNotificationListener
Since:
2.5.2/**
 * Registrar object that associates a specific {@link javax.management.NotificationListener}
 * with one or more MBeans in an {@link javax.management.MBeanServer}
 * (typically via a {@link javax.management.MBeanServerConnection}).
 *
 * @author Juergen Hoeller
 * @since 2.5.2
 * @see #setServer
 * @see #setMappedObjectNames
 * @see #setNotificationListener
 */
public class NotificationListenerRegistrar extends NotificationListenerHolder
		implements InitializingBean, DisposableBean {

	
Logger available to subclasses. /** Logger available to subclasses. */
	protected final Log logger = LogFactory.getLog(getClass());

	private final ConnectorDelegate connector = new ConnectorDelegate();

	@Nullable
	private MBeanServerConnection server;

	@Nullable
	private JMXServiceURL serviceUrl;

	@Nullable
	private Map<String, ?> environment;

	@Nullable
	private String agentId;

	@Nullable
	private ObjectName[] actualObjectNames;


	
Set the MBeanServerConnection used to connect to the MBean which all invocations are routed to. /**
	 * Set the {@code MBeanServerConnection} used to connect to the
	 * MBean which all invocations are routed to.
	 */
	public void setServer(MBeanServerConnection server) {
		this.server = server;
	}

	
Specify the environment for the JMX connector.
See Also:
connect.connect(JMXServiceURL, Map)/**
	 * Specify the environment for the JMX connector.
	 * @see javax.management.remote.JMXConnectorFactory#connect(javax.management.remote.JMXServiceURL, java.util.Map)
	 */
	public void setEnvironment(@Nullable Map<String, ?> environment) {
		this.environment = environment;
	}

	
Allow Map access to the environment to be set for the connector,
with the option to add or override specific entries.
Useful for specifying entries directly, for example via
"environment[myKey]". This is particularly useful for
adding or overriding entries in child bean definitions.
/**
	 * Allow Map access to the environment to be set for the connector,
	 * with the option to add or override specific entries.
	 * <p>Useful for specifying entries directly, for example via
	 * "environment[myKey]". This is particularly useful for
	 * adding or overriding entries in child bean definitions.
	 */
	@Nullable
	public Map<String, ?> getEnvironment() {
		return this.environment;
	}

	
Set the service URL of the remote MBeanServer. /**
	 * Set the service URL of the remote {@code MBeanServer}.
	 */
	public void setServiceUrl(String url) throws MalformedURLException {
		this.serviceUrl = new JMXServiceURL(url);
	}

	
Set the agent id of the MBeanServer to locate. 
Default is none. If specified, this will result in an attempt being made to locate the attendant MBeanServer, unless the "serviceUrl" property has been set. 
See Also:
Specifying the empty String indicates the platform MBeanServer./**
	 * Set the agent id of the {@code MBeanServer} to locate.
	 * <p>Default is none. If specified, this will result in an
	 * attempt being made to locate the attendant MBeanServer, unless
	 * the {@link #setServiceUrl "serviceUrl"} property has been set.
	 * @see javax.management.MBeanServerFactory#findMBeanServer(String)
	 * <p>Specifying the empty String indicates the platform MBeanServer.
	 */
	public void setAgentId(String agentId) {
		this.agentId = agentId;
	}


	@Override
	public void afterPropertiesSet() {
		if (getNotificationListener() == null) {
			throw new IllegalArgumentException("Property 'notificationListener' is required");
		}
		if (CollectionUtils.isEmpty(this.mappedObjectNames)) {
			throw new IllegalArgumentException("Property 'mappedObjectName' is required");
		}
		prepare();
	}

	
Registers the specified NotificationListener. 
Ensures that an MBeanServerConnection is configured and attempts to detect a local connection if one is not supplied. /**
	 * Registers the specified {@code NotificationListener}.
	 * <p>Ensures that an {@code MBeanServerConnection} is configured and attempts
	 * to detect a local connection if one is not supplied.
	 */
	public void prepare() {
		if (this.server == null) {
			this.server = this.connector.connect(this.serviceUrl, this.environment, this.agentId);
		}
		try {
			this.actualObjectNames = getResolvedObjectNames();
			if (this.actualObjectNames != null) {
				if (logger.isDebugEnabled()) {
					logger.debug("Registering NotificationListener for MBeans " + Arrays.asList(this.actualObjectNames));
				}
				for (ObjectName actualObjectName : this.actualObjectNames) {
					this.server.addNotificationListener(
							actualObjectName, getNotificationListener(), getNotificationFilter(), getHandback());
				}
			}
		}
		catch (IOException ex) {
			throw new MBeanServerNotFoundException(
					"Could not connect to remote MBeanServer at URL [" + this.serviceUrl + "]", ex);
		}
		catch (Exception ex) {
			throw new JmxException("Unable to register NotificationListener", ex);
		}
	}

	
Unregisters the specified NotificationListener. /**
	 * Unregisters the specified {@code NotificationListener}.
	 */
	@Override
	public void destroy() {
		try {
			if (this.server != null && this.actualObjectNames != null) {
				for (ObjectName actualObjectName : this.actualObjectNames) {
					try {
						this.server.removeNotificationListener(
								actualObjectName, getNotificationListener(), getNotificationFilter(), getHandback());
					}
					catch (Exception ex) {
						if (logger.isDebugEnabled()) {
							logger.debug("Unable to unregister NotificationListener", ex);
						}
					}
				}
			}
		}
		finally {
			this.connector.close();
		}
	}

}