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Java > Open Source Codes > com > jcorporate > expresso > core > dbobj > CacheStatEntry


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64 package com.jcorporate.expresso.core.dbobj;
65
66 import com.jcorporate.expresso.core.misc.StringUtil;
67
68
69 /**
70  * Cache Statistic Entry. Used by the DBObject system for tracking cache
71  * hit statistics
72  *
73  * @version 1.0
74  */
75 public class CacheStatEntry
76         extends Object JavaDoc implements Comparable JavaDoc {
77
78     private String JavaDoc dbobjName = null;
79     private String JavaDoc dbName = null;
80     private int readCount = 0;
81     private int cacheHits = 0;
82     private int cacheMisses = 0;
83
84     /**
85      * Creates new CacheStatEntry
86      *
87      * @param newName the new dbobject name
88      * @param newDBName the data context for the name
89      */
90     public CacheStatEntry(String JavaDoc newName, String JavaDoc newDBName) {
91         dbobjName = newName;
92         dbName = StringUtil.notNull(newDBName);
93
94         if (dbName.equals("")) {
95             dbName = "default";
96         }
97     }
98
99     /**
100      * Retrieve the overall read count for dbobjects
101      *
102      * @return integer
103      */
104     public int getReadCount() {
105         return readCount;
106     }
107
108     /**
109      * Retrieve the number of cache hits
110      *
111      * @return integer
112      */
113     public int getCacheHits() {
114         return cacheHits;
115     }
116
117     /**
118      * Retrieve the number of cache misses
119      *
120      * @return integer
121      */
122     public int getCacheMisses() {
123         return cacheMisses;
124     }
125
126     /**
127      * Retrieve the data context of the stat entry
128      *
129      * @return java.lang.String
130      */
131     public String JavaDoc getDataContext() {
132         return dbName;
133     }
134
135     /**
136      * Retrieve the classname of the DBObject for this
137      * cache stat
138      *
139      * @return java.lang.String
140      */
141     public String JavaDoc getDBObjName() {
142         return dbobjName;
143     }
144
145     /**
146      * Increment the counts for the particular class name. Increments
147      * the read count and either the cache hit or cache miss
148      *
149      * @param cached true if we got a cache hit, false if we got a cache
150      * miss
151      */
152     public synchronized void incCounts(boolean cached) {
153         if (cached) {
154             cacheHits++;
155         } else {
156             cacheMisses++;
157         }
158
159         readCount++;
160     }
161
162     /**
163      * Compares this object with the specified object for order.
164      * <p/>
165      * order by hit rate, hits/misses
166      *
167      * @param o the Object to be compared.
168      * @return a negative integer, zero, or a positive integer as this object
169      * is less than, equal to, or greater than the specified object.
170      * @throws ClassCastException if the specified object's type prevents it
171      * from being compared to this Object.
172      */
173     public int compareTo(Object JavaDoc o) {
174         int result = 0;
175         CacheStatEntry entry = (CacheStatEntry) o;
176
177         // want lower hitrates first
178 Float JavaDoc myhitrate = new Float JavaDoc((float) this.getCacheHits() / (float) getReadCount());
179         Float JavaDoc hitrate = new Float JavaDoc((float) entry.getCacheHits() / (float) entry.getReadCount());
180         result = myhitrate.compareTo(hitrate);
181         if (result == 0) {
182             //secondary: # of reads HIGHER is first
183 result = new Integer JavaDoc(entry.getReadCount()).compareTo(new Integer JavaDoc(getReadCount()));
184         }
185         return result;
186     }
187 }
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