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/*
 * $Id: EJBCacheStats.java,v 1.2 2007/05/05 05:31:02 tcfujii Exp $
 * $Date: 2007/05/05 05:31:02 $
 * $Revision: 1.2 $
 */

package com.sun.appserv.management.monitor.statistics;
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.
 */
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 getBeansInCache();
    
    /**
     * Returns the number of passivations of a Stateful Session Bean, as a CountStatistic.
	 * @return		an instance of {@link CountStatistic}
     */
    public CountStatistic getPassivations();
    
    /**
     * Returns the number of errors in passivating a Stateful Session Bean, as a CountStatistic.
	 * Must be less than or equal to {@link #getPassivations}
	 * @return		an instance of {@link CountStatistic}
     */
    public CountStatistic getPassivationErrors();
    
    /**
     * Returns the number of removed Expired Sessions as a CountStatistic.
	 * @return		an instance of {@link CountStatistic}
     */
    public CountStatistic getExpiredSessionsRemoved();
    
    /**
     * Returns the number of errors in passivating a Stateful Session Bean, as a CountStatistic.
	 * Must be less than or equal to {@link #getPassivations}
	 * @return		an instance of {@link CountStatistic}
     */
    public CountStatistic getPassivationSuccesses();
}