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/*
* Copyright 2004-2005 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
/*
* $Id: MutableCountStatisticImpl.java,v 1.3 2007/05/05 05:25:48 tcfujii Exp $
* $Date: 2007/05/05 05:25:48 $
* $Revision: 1.3 $
*/
package com.sun.enterprise.admin.monitor.stats;
import javax.management.j2ee.statistics.CountStatistic;
import com.sun.enterprise.admin.monitor.stats.CountStatisticImpl;
import javax.management.j2ee.statistics.Statistic;
/** An implementation of MutableCountStatistic that provides ways to change the state externally through mutators.
* Convenience class that is useful for components that gather the statistical data.
* @author Kedar Mhaswade
* @see CountStatisticImpl for an immutable implementation
* @since S1AS8.0
* @version 1.0
*/
public class MutableCountStatisticImpl implements CountStatistic, MutableCountStatistic {
private final CountStatistic initial;
private long count;
private long lastSampleTime;
private long startTime;
/** Constructs an instance of MutableCountStatistic that encapsulates the given Statistic.
* The only parameter denotes the initial state of this statistic. It is
* guaranteed that the initial state is preserved internally, so that one
* can reset to the initial state.
* @param initial an instance of CountStatistic that represents initial state
*/
public MutableCountStatisticImpl(CountStatistic initial) {
this.initial = initial;
this.count = initial.getCount();
this.lastSampleTime = initial.getLastSampleTime();
this.startTime = lastSampleTime;
}
/** Resets to the initial state. It is guaranteed that following changes occur
* to the statistic if this method is called:
* <ul>
* <li> The current value is reset to its initial value. </li>
* <li> The lastSampleTime is reset to <b> current time in milliseconds. </b> </li>
* <li> The startTime is reset to lastSampleTime. </li>
* </ul>
* The remaining meta data in the statistic is unchanged.
*/
public void reset() {
this.count = initial.getCount();
this.lastSampleTime = System.currentTimeMillis();
this.startTime = this.lastSampleTime;
}
/** Changes the value of the encapsulated CountStatistic to the given value.
* Since this is the only mutator exposed here, here are the other side effects
* of calling this method:
* <ul>
* <li> lastSampleTime is set to <b> current time in milliseconds. </b> </li>
* </ul>
* In a real-time system with actual probes for measurement, the lastSampleTime
* could be different from the instant when this method is called, but that is deemed insignificant.
* @param count long that represents the current value of the Statistic.
*/
public void setCount(long count) {
this.count = count;
this.lastSampleTime = System.currentTimeMillis();
}
/** This method is the essence of this class. It provides the read-only view of encapsulated
* Statistic. If the clients have to know the Statistic, this is what should
* be called by actual data collecting component to return the value to them.
* The principle advantage is from the data collecting component's standpoint, in
* that it does not have to create instances of CountStatistic when its
* current value is queried/measured.
* @see #reset
* @see #setCount
* @return instance of CountStatistic
*/
public Statistic unmodifiableView() {
return ( new CountStatisticImpl(
this.count, // this is the actual changing statistic
initial.getName(), // name does not change
initial.getUnit(), // unit does not change
initial.getDescription(), // description does not change
this.lastSampleTime, // changes all the time!
this.startTime // changes if reset is called earlier
));
}
public long getLastSampleTime() {
return ( this.lastSampleTime );
}
public long getStartTime() {
return ( this.startTime );
}
public String getName() {
return ( initial.getName() );
}
public String getDescription() {
return ( initial.getDescription() );
}
public String getUnit() {
return ( initial.getUnit());
}
public Statistic modifiableView() {
return ( this );
}
public long getCount() {
return ( this.count );
}
/* hack: bug 5045413 */
public void setDescription (final String s) {
try {
((StatisticImpl)this.initial).setDescription(s);
}
catch(final Exception e) {
}
}
}
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