QueryCache


1   /*
2    * Enhydra Java Application Server Project
3    *
4    * The contents of this file are subject to the Enhydra Public License
5    * Version 1.1 (the "License"); you may not use this file except in
6    * compliance with the License. You may obtain a copy of the License on
7    * the Enhydra web site ( http://www.enhydra.org/ ).
8    *
9    * Software distributed under the License is distributed on an "AS IS"
10   * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
11   * the License for the specific terms governing rights and limitations
12   * under the License.
13   *
14   * The Initial Developer of the Enhydra Application Server is Lutris
15   * Technologies, Inc. The Enhydra Application Server and portions created
16   * by Lutris Technologies, Inc. are Copyright Lutris Technologies, Inc.
17   * All Rights Reserved.
18   *
19   */
20  package org.enhydra.dods.cache;
21  
22  import java.util.Vector  ;
23  
24  /**
25   * This abstract class contains data and mechanisms needed for caching data
26   * objects (or DataStruct objects) and queries and provides cache configuration
27   * and administration.
28   *
29   * @author    Tanja Jovanovic
30   * @author    Nenad Vico
31   * @author    Zorica Suvajdzin
32   * @version   2.0  15.06.2003.
33   */
34  public abstract class QueryCache extends DataStructCache {
35  
36      /**
37       * Creates new QueryCacheItem instance.
38       *
39       * @param dbName Database name.
40       * @return Created QueryCacheItem.
41       */
42      public abstract QueryCacheItem newQueryCacheItemInstance(String   dbName);
43  
44      /**
45       * Returns QueryCacheItem object for specified database and simple query,
46       * if exists, otherwise null.
47       *
48       * @param dbName Database name.
49       * @param query Query in form of String.
50       * @return QueryCacheItem object.
51       */
52      public abstract QueryCacheItem getSimpleQueryCacheItem(String   dbName, String   query);
53  
54      /**
55       * Returns QueryCacheItem object for specified database and complex query,
56       * if exists, otherwise null.
57       *
58       * @param dbName Database name.
59       * @param query Query in form of String.
60       * @return QueryCacheItem object.
61       */
62      public abstract QueryCacheItem getComplexQueryCacheItem(String   dbName, String   query);
63  
64      /**
65       * Returns QueryCacheItem object for specified database and multi join query,
66       * if exists, otherwise null.
67       *
68       * @param dbName Database name.
69       * @param query Query in form of String.
70       * @return QueryCacheItem object.
71       */
72      public abstract QueryCacheItem getMultiJoinQueryCacheItem(String   dbName, String   query);
73      
74      /**
75       * Adds simple query to simple query cache.
76       *
77       * @param queryItem Query that will be added to simple query cache.
78       * @return Query added to simple query cache.
79       */
80      public abstract QueryCacheItem addSimpleQuery(QueryCacheItem queryItem);
81  
82      /**
83       * Removes simple query from simple query cache.
84       *
85       * @param queryItem QueryItem that will be removed from simple query cache.
86       * @return QueryItem removed from simple query cache.
87       */
88      public abstract QueryCacheItem removeSimpleQuery(QueryCacheItem queryItem);
89  
90      /**
91       * Adds complex query to complex query cache.
92       *
93       * @param queryItem Query that will be added to complex query cache.
94       * @return Query added to complex query cache.
95       */
96      public abstract QueryCacheItem addComplexQuery(QueryCacheItem queryItem);
97  
98      /**
99       * Removes complex query from complex query cache.
100      *
101      * @param queryItem Query that will be removed from complex query cache.
102      * @return Query removed from complex query cache.
103      */
104     public abstract QueryCacheItem removeComplexQuery(QueryCacheItem queryItem);
105     
106     /**
107      * Adds multi join query to complex query cache.
108      *
109      * @param queryItem Query that will be added to multi join query cache.
110      * @return Query added to multi join query cache.
111      */
112     public abstract QueryCacheItem addMultiJoinQuery(QueryCacheItem queryItem);
113 
114     /**
115      * Removes multi join query from complex query cache.
116      *
117      * @param queryItem Query that will be removed from multi join query cache.
118      * @return Query removed from multi join query cache.
119      */
120     public abstract QueryCacheItem removeMultiJoinQuery(QueryCacheItem queryItem);
121 
122     /**
123      * Returns query results from simple query cache.
124      *
125      * @param dbName Database name.
126      * @param query Query for which are results searched in simple query cache.
127      * @return Query results retrieved from simple cache, or null, if there are
128      * no results retrieved from simple query cache.
129      */
130     public abstract QueryResult getSimpleQueryResults(String   dbName, String   query);
131 
132     /**
133      * Returns query results from simple query cache.
134      *
135      * @param dbName Database name.
136      * @param query Query for which are results searched in simple query cache.
137      * @param limit Specified number of results (database limit and read skip).
138      * @param maxdb Number of rows retrieved from database (or cache).
139      * @return Query results retrieved from simple cache, or null, if there are
140      * no results retrieved from simple query cache.
141      */
142     public abstract QueryResult getSimpleQueryResults(String   dbName, String   query, int limit, int maxdb);
143 
144     /**
145      * Returns query results from simple query cache.
146      *
147      * @param dbName Database name.
148      * @param query Query for which are results searched in simple query cache.
149      * @param limit Specified number of results (database limit and read skip).
150      * @param maxdb Number of rows retrieved from database (or cache).
151      * @param unique If true, only unique results are returned.
152      * @return Query results retrieved from simple cache, or null, if there are
153      * no results retrieved from simple query cache.
154      */
155     public abstract QueryResult getSimpleQueryResults(String   dbName, String   query, int limit, int maxdb, boolean unique);
156 
157     /**
158      * Returns query results from complex query cache.
159      *
160      * @param dbName Database name.
161      * @param query Query for which are results searched in complex query cache.
162      * @return Query results retrieved from complex cache, or null, if there are
163      * no results retrieved from complex query cache.
164      */
165     public abstract QueryResult getComplexQueryResults(String   dbName, String   query);
166 
167     /**
168      * Returns query results from complex query cache.
169      *
170      * @param dbName Database name.
171      * @param query Query for which are results searched in complex query cache.
172      * @param limit Specified number of results (database limit and read skip).
173      * @param maxdb Number of rows retrieved from database (or cache).
174      * @return Query results retrieved from complex cache, or null, if there are
175      * no results retrieved from complex query cache.
176      */
177     public abstract QueryResult getComplexQueryResults(String   dbName, String   query, int limit, int maxdb);
178 
179     /**
180      * Returns query results from complex query cache.
181      *
182      * @param dbName Database name.
183      * @param query Query for which are results searched in complex query cache.
184      * @param limit Specified number of results (database limit and read skip).
185      * @param maxdb Number of rows retrieved from database (or cache).
186      * @param unique If true, only unique results are returned.
187      * @return Query results retrieved from complex cache, or null, if there are
188      * no results retrieved from complex query cache.
189      */
190     public abstract QueryResult getComplexQueryResults(String   dbName, String   query, int limit, int maxdb, boolean unique);
191 
192     /**
193      * Returns query results from multi join query cache.
194      *
195      * @param dbName Database name.
196      * @param query Query for which are results searched in multi join query cache.
197      * @return Query results retrieved from multi join cache, or null, if there are
198      * no results retrieved from multi join query cache.
199      */
200     public abstract QueryResult getMultiJoinQueryResults(String   dbName, String   query);
201 
202     /**
203      * Returns query results from multi join query cache.
204      *
205      * @param dbName Database name.
206      * @param query Query for which are results searched in multi join query cache.
207      * @param limit Specified number of results (database limit and read skip).
208      * @param maxdb Number of rows retrieved from database (or cache).
209      * @return Query results retrieved from multi join cache, or null, if there 
210      * are no results retrieved from multi join query cache.
211      */
212     public abstract QueryResult getMultiJoinQueryResults(String   dbName, String   query, int limit, int maxdb);
213 
214     /**
215      * Returns query results from multi join query cache.
216      *
217      * @param dbName Database name.
218      * @param query Query for which are results searched in multi join query cache.
219      * @param limit Specified number of results (database limit and read skip).
220      * @param maxdb Number of rows retrieved from database (or cache).
221      * @param unique If true, only unique results are returned.
222      * @return Query results retrieved from multi join cache, or null, if there 
223      * are no results retrieved from multi join query cache.
224      */
225     public abstract QueryResult getMultiJoinQueryResults(String   dbName, String   query, int limit, int maxdb, boolean unique);
226     
227     /**
228      * Returns query results from simple or complex query cache.
229      *
230      * @param dbName Database name.
231      * @param query Query for which are results searched in simple and complex
232      * query cache.
233      * @return Query results retrieved from simple or complex cache, or null,
234      * if there are no results retrieved from simple and complex query cache.
235      */
236     public abstract QueryResult getQueryResults(String   dbName, String   query);
237     
238     /**
239      *
240      */
241     final synchronized void lockSimpleComplexQCache() {
242         lockedSimpleComplexQCache = true;
243     }
244 
245     /**
246      *
247      */
248     final synchronized void unlockSimpleComplexQCache() {
249         lockedSimpleComplexQCache = false;
250     }
251 
252     /**
253      *
254      */
255     protected final synchronized boolean isLockedSimpleComplexQCache() {
256         return lockedSimpleComplexQCache;
257     }
258     
259    /**
260      *
261      */
262     final synchronized void lockMultiJoinQCache() {
263         lockedMultiJoinQCache = true;
264     }
265 
266     /**
267      *
268      */
269     final synchronized void unlockMultiJoinQCache() {
270         lockedMultiJoinQCache = false;
271     }
272 
273     /**
274      *
275      */
276     protected final synchronized boolean isLockedMultiJoinQCache() {
277         return lockedMultiJoinQCache;
278     }
279 
280     /**
281      *
282      */
283     public abstract void removeEntries(Vector   vec);
284 
285     /**
286      *
287      */
288     public abstract void removeEntries() ;
289 
290     /**
291      *
292      */
293     public abstract void emptyEntries(Vector   vec, boolean incrementVersion) ;
294 
295     /**
296      *
297      */
298     public abstract void emptyEntries() ;
299 
300     /**
301      *
302      */ 
303     public abstract void makeInvisible(String   cacheHandle) ;
304 
305 
306     /**
307      *
308      */ 
309     public abstract void makeVisible(String   cacheHandle);
310     
311 
312     public abstract CacheAdministration getCacheAdministration(int cacheType);
313     
314     /**
315      *
316      */
317     private boolean lockedSimpleComplexQCache = false;    
318     
319     /**
320      *
321      */
322     private boolean lockedMultiJoinQCache = false;    
323 }
324
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