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1 /*
2
3  ============================================================================
4                    The Apache Software License, Version 1.1
5  ============================================================================
6  
7  Copyright (C) 1999-2003 The Apache Software Foundation. All rights reserved.
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9  Redistribution and use in source and binary forms, with or without modifica-
10  tion, are permitted provided that the following conditions are met:
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13     this list of conditions and the following disclaimer.
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16     this list of conditions and the following disclaimer in the documentation
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20     include the following acknowledgment: "This product includes software
21     developed by the Apache Software Foundation (http://www.apache.org/)."
22     Alternately, this acknowledgment may appear in the software itself, if
23     and wherever such third-party acknowledgments normally appear.
24  
25  4. The names "Jakarta", "Avalon", "Excalibur" and "Apache Software Foundation"
26     must not be used to endorse or promote products derived from this software
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30  5. Products derived from this software may not be called "Apache", nor may
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32     Apache Software Foundation.
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45  This software consists of voluntary contributions made by many individuals
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49 */

50 package org.apache.excalibur.instrument.manager;
51
52 import org.apache.avalon.framework.configuration.Configuration;
53 import org.apache.avalon.framework.configuration.ConfigurationException;
54 import org.apache.avalon.framework.configuration.DefaultConfiguration;
55 import org.apache.excalibur.instrument.manager.interfaces.InstrumentManagerClient;
56
57 /**
58  * A InstrumentSample which stores the mean value set during the sample
59  * period.
60  *
61  * @author <a HREF="mailto:leif@tanukisoftware.com">Leif Mortenson</a>
62  * @version CVS $Revision: 1.3 $ $Date: 2003/02/25 16:28:16 $
63  * @since 4.1
64  */

65 class MeanValueInstrumentSample
66     extends AbstractValueInstrumentSample
67 {
68     /** Total of all values seen during the sample period. */
69     private long m_valueTotal;
70     
71     /*---------------------------------------------------------------
72      * Constructors
73      *-------------------------------------------------------------*/

74     /**
75      * Creates a new MeanValueInstrumentSample
76      *
77      * @param instrumentProxy The InstrumentProxy which owns the
78      * InstrumentSample.
79      * @param name The name of the new InstrumentSample.
80      * @param interval The sample interval of the new InstrumentSample.
81      * @param size The number of samples to store as history. Assumes that size is at least 1.
82      * @param description The description of the new InstrumentSample.
83      * @param lease The length of the lease in milliseconds.
84      */

85     MeanValueInstrumentSample( InstrumentProxy instrumentProxy,
86                                String JavaDoc name,
87                                long interval,
88                                int size,
89                                String JavaDoc description,
90                                long lease )
91     {
92         super( instrumentProxy, name, interval, size, description, lease );
93     }
94     
95     /*---------------------------------------------------------------
96      * InstrumentSample Methods
97      *-------------------------------------------------------------*/

98     /**
99      * Returns the type of the Instrument Sample.
100      *
101      * @return The type of the Instrument Sample.
102      */

103     public int getType()
104     {
105         return InstrumentManagerClient.INSTRUMENT_SAMPLE_TYPE_MEAN;
106     }
107     
108     /*---------------------------------------------------------------
109      * AbstractInstrumentSample Methods
110      *-------------------------------------------------------------*/

111     /**
112      * The current sample has already been stored. Reset the current sample
113      * and move on to the next.
114      * <p>
115      * Should only be called when synchronized.
116      */

117     protected void advanceToNextSample()
118     {
119         // Leave the value as is so that it will propagate to the next sample
120
// if needed. But reset the value count so that new values will not
121
// be affected by the old.
122
m_valueCount = 0;
123     }
124     
125     /**
126      * Allow subclasses to add information into the saved state.
127      *
128      * @param state State configuration.
129      */

130     protected void saveState( DefaultConfiguration state )
131     {
132         super.saveState( state );
133         
134         state.setAttribute( "value-total", Long.toString( m_valueTotal ) );
135     }
136     
137     /**
138      * Used to load the state, called from AbstractInstrumentSample.loadState();
139      * <p>
140      * Should only be called when synchronized.
141      *
142      * @param value Current value loaded from the state.
143      * @param state Configuration object to load state from.
144      *
145      * @throws ConfigurationException If there were any problems loading the
146      * state.
147      */

148     protected void loadState( int value, Configuration state )
149         throws ConfigurationException
150     {
151         super.loadState( value, state );
152         
153         m_valueTotal = state.getAttributeAsLong( "value-total" );
154     }
155     
156     /**
157      * Called after a state is loaded if the sample period is not the same
158      * as the last period saved.
159      */

160     protected void postSaveNeedsReset()
161     {
162         super.postSaveNeedsReset();
163         
164         m_valueTotal = 0;
165     }
166     
167     /*---------------------------------------------------------------
168      * AbstractValueInstrumentSample Methods
169      *-------------------------------------------------------------*/

170     /**
171      * Sets the current value of the sample. The value will be set as the
172      * mean of the new value and other values seen during the sample period.
173      *
174      * @param value New sample value.
175      * @param time Time that the new sample arrives.
176      */

177     protected void setValueInner( int value, long time )
178     {
179         int sampleValue;
180         long sampleTime;
181         
182         synchronized(this)
183         {
184             update( time );
185             
186             if ( m_valueCount > 0 )
187             {
188                 // Additional sample
189
m_valueCount++;
190                 m_valueTotal += value;
191                 m_value = (int)(m_valueTotal / m_valueCount);
192             }
193             else
194             {
195                 // First value of this sample.
196
m_valueCount = 1;
197                 m_valueTotal = m_value = value;
198             }
199             sampleValue = m_value;
200             sampleTime = m_time;
201         }
202         
203         updateListeners( sampleValue, sampleTime );
204     }
205 }
206
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