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

/*
 * $Id: EJBCacheStats.java,v 1.3 2007/05/05 05:25:47 tcfujii Exp $
 * $Date: 2007/05/05 05:25:47 $
 * $Revision: 1.3 $
 */

package com.sun.enterprise.admin.monitor.stats;
import javax.management.j2ee.statistics.Stats;
import javax.management.j2ee.statistics.CountStatistic;
import javax.management.j2ee.statistics.BoundedRangeStatistic;

/**
 * A Stats interface to represent the statistics exposed by the Enterprise Bean Cache.
 * This is based on the statistics that were exposed in S1AS7.0. An implementation of EJB Cache
 * should provide statistical data by implementing this interface.
 * @author Muralidhar Vempaty
 * @author Kedar Mhaswade
 * @since S1AS8.0
 * @version 1.0
 */
public interface EJBCacheStats extends Stats {
    
    /**
     * Returns the number of times a user request fails to find an EJB in associated EJB cache instance, as a CountStatistic.
     * @return		an instance of {@link BoundedRangeStatistic}
     */
    public BoundedRangeStatistic getCacheMisses();
    
    /**
     * Returns the number of times a user request hits an EJB in associated EJB cache instance, as a CountStatistic.
	 * @return		an instance of {@link BoundedRangeStatistic}
     */
    public BoundedRangeStatistic getCacheHits();
    
    /** Returns total number of EJBs in the associated EJB Cache, as a BoundedRangeStatistic. 
	 * Note that this returns the various statistical values like maximum and minimum value attained
	 * as a part of the return value.
	 * @return		an instance of {@link BoundedRangeStatistic}
     */
    public BoundedRangeStatistic getNumBeansInCache();
    
    /**
     * Returns the number of passivations of a Stateful Session Bean, as a CountStatistic.
	 * @return		an instance of {@link CountStatistic}
     */
    public CountStatistic getNumPassivations();
    
    /**
     * Returns the number of errors in passivating a Stateful Session Bean, as a CountStatistic.
	 * Must be less than or equal to {@link #getNumPassivations}
	 * @return		an instance of {@link CountStatistic}
     */
    public CountStatistic getNumPassivationErrors();
    
    /**
     * Returns the number of removed Expired Sessions as a CountStatistic.
	 * @return		an instance of {@link CountStatistic}
     */
    public CountStatistic getNumExpiredSessionsRemoved();
    
    /**
     * Returns the number of errors in passivating a Stateful Session Bean, as a CountStatistic.
	 * Must be less than or equal to {@link #getNumPassivations}
	 * @return		an instance of {@link CountStatistic}
     */
    public CountStatistic getNumPassivationSuccess();
}