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/*
 * Copyright 2004-2005 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*
 * MonitoringLevelListener.java
 *
 * Created on August 13, 2003, 2:15 PM
 */

package com.sun.enterprise.admin.monitor.registry;

/**
 * Implementation of this interface enables notifications to 
 * be received for change in monitoring level from a prior 
 * level to a new one. Monitoring levels are defined by the 
 * constants class MonitoringLevel and are currently defined as 
 * OFF, LOW and HIGH.
 * @author  <href=mailto:shreedhar.ganapathy@sun.com>Shreedhar Ganapathy
 */
public interface MonitoringLevelListener {
    /**
     * Sets the monitoring level to a new level. Values are defined by 
     * MonitoringLevel.OFF, MonitoringLevel.LOW, and MonitoringLevel.High
     * @param level corresponding to MonitoringLevel OFF, LOW or HIGH
     * @deprecated
     */
    public void setLevel(MonitoringLevel level);
    
	/**
	 * Method to convey the change in monitoring level. It is a usual practice that
	 * various components may have <em> single instance of listener </em> to listen
	 * to the changes in monitoring-level for various registered Stats objects. This
	 * method gives a context for such components to be returned when it is
	 * called.
	 * @deprecated
	 * @param from		the MonitoringLevel before the change
	 * @param to		the MonitoringLevel after the change
	 * @param handback	the Stats object that was passed to the registry during registration. It
	 * is guaranteed that it will be unchanged by monitoring framework.
	 */
	public void changeLevel(MonitoringLevel from, MonitoringLevel to, 
		javax.management.j2ee.statistics.Stats handback);

	/**
	 * Method to convey the change in monitoring level. The configuration
	 * of monitoring pertains to certain components like ejb-container, web-container,
	 * orb, transaction-service, connection-pools, thread-pools etc. The third
	 * parameter loosely corresponds to the configuration in domain.xml as follows:
	 * <ul>
	 * <li> connector-connection-pool : MonitoredObjectType#CONNECTOR_CONN_POOL </li>
	 * <li> ejb-container : MonitoredObjectType#EJB </li>
	 * <li> http-service, http-listeners etc. : MonitoredObjectType#HTTP_SERVICE </li>
	 * <li> jdbc-connection-pool : MonitoredObjectType#JDBC_CONN_POOL </li>
	 * <li> orb : MonitoredObjectType#ORB </li>
	 * <li> thread-pool : MonitoredObjectType#THREAD_POOL </li>
	 * <li> transaction-service : MonitoredObjectType#TRANSACTION_SERVICE </li>
	 * <li> web-container : MonitoredObjectType#WEB_COMPONENT </li>
	 * <li> </li>
	 * </ul>
	 * The core components are expected to follow the above.
	 * When the level changes through administrative interfaces, the notification
	 * is sent to the registered listeners for corresponding types and thus the
	 * dynamic reconfiguration is done.
	 * @param from		the MonitoringLevel before the change
	 * @param to		the MonitoringLevel after the change
	 * @param type		the MonitoredObjectType that had the level changed
	 */
	public void changeLevel(MonitoringLevel from, MonitoringLevel to,
		MonitoredObjectType type);
}