1   /**
2    * Copyright (c) 2000-2009 Liferay, Inc. All rights reserved.
3    *
4    *
5    *
6    *
7    * The contents of this file are subject to the terms of the Liferay Enterprise
8    * Subscription License ("License"). You may not use this file except in
9    * compliance with the License. You can obtain a copy of the License by
10   * contacting Liferay, Inc. See the License for the specific language governing
11   * permissions and limitations under the License, including but not limited to
12   * distribution rights of the Software.
13   *
14   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
15   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
16   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
17   * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
18   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
19   * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
20   * SOFTWARE.
21   */
22  
23  package com.liferay.portal.search.lucene;
24  
25  import com.liferay.portal.kernel.dao.jdbc.DataAccess;
26  import com.liferay.portal.kernel.log.Log;
27  import com.liferay.portal.kernel.log.LogFactoryUtil;
28  import com.liferay.portal.kernel.search.Field;
29  import com.liferay.portal.kernel.search.SearchEngineUtil;
30  import com.liferay.portal.kernel.util.FileUtil;
31  import com.liferay.portal.kernel.util.InfrastructureUtil;
32  import com.liferay.portal.kernel.util.PortalClassLoaderUtil;
33  import com.liferay.portal.kernel.util.PropsKeys;
34  import com.liferay.portal.kernel.util.StringPool;
35  import com.liferay.portal.kernel.util.StringUtil;
36  import com.liferay.portal.kernel.util.Validator;
37  import com.liferay.portal.util.PropsUtil;
38  import com.liferay.portal.util.PropsValues;
39  import com.liferay.util.lucene.KeywordsUtil;
40  
41  import java.io.IOException;
42  import java.io.StringReader;
43  
44  import java.sql.Connection;
45  import java.sql.DatabaseMetaData;
46  import java.sql.ResultSet;
47  import java.sql.Statement;
48  
49  import java.util.Date;
50  import java.util.HashSet;
51  import java.util.Map;
52  import java.util.Set;
53  import java.util.concurrent.ConcurrentHashMap;
54  
55  import javax.sql.DataSource;
56  
57  import org.apache.lucene.analysis.Analyzer;
58  import org.apache.lucene.analysis.TokenStream;
59  import org.apache.lucene.analysis.WhitespaceAnalyzer;
60  import org.apache.lucene.document.Document;
61  import org.apache.lucene.index.IndexReader;
62  import org.apache.lucene.index.IndexWriter;
63  import org.apache.lucene.index.Term;
64  import org.apache.lucene.queryParser.ParseException;
65  import org.apache.lucene.queryParser.QueryParser;
66  import org.apache.lucene.search.BooleanClause;
67  import org.apache.lucene.search.BooleanQuery;
68  import org.apache.lucene.search.IndexSearcher;
69  import org.apache.lucene.search.Query;
70  import org.apache.lucene.search.TermQuery;
71  import org.apache.lucene.search.WildcardQuery;
72  import org.apache.lucene.search.highlight.Highlighter;
73  import org.apache.lucene.search.highlight.QueryScorer;
74  import org.apache.lucene.search.highlight.QueryTermExtractor;
75  import org.apache.lucene.search.highlight.SimpleFragmenter;
76  import org.apache.lucene.search.highlight.SimpleHTMLFormatter;
77  import org.apache.lucene.search.highlight.WeightedTerm;
78  import org.apache.lucene.store.Directory;
79  import org.apache.lucene.store.FSDirectory;
80  import org.apache.lucene.store.RAMDirectory;
81  import org.apache.lucene.store.jdbc.JdbcDirectory;
82  import org.apache.lucene.store.jdbc.JdbcStoreException;
83  import org.apache.lucene.store.jdbc.dialect.Dialect;
84  import org.apache.lucene.store.jdbc.lock.JdbcLock;
85  import org.apache.lucene.store.jdbc.support.JdbcTemplate;
86  
87  /**
88   * <a href="LuceneUtil.java.html"><b><i>View Source</i></b></a>
89   *
90   * @author Brian Wing Shun Chan
91   * @author Harry Mark
92   */
93  public class LuceneUtil {
94  
95      public static void acquireLock(long companyId) {
96          try {
97              _instance._sharedWriter.acquireLock(companyId, true);
98          }
99          catch (InterruptedException ie) {
100             _log.error(ie);
101         }
102     }
103 
104     public static void addDate(Document doc, String field, Date value) {
105         doc.add(LuceneFields.getDate(field, value));
106     }
107 
108     public static void addExactTerm(
109         BooleanQuery booleanQuery, String field, boolean value) {
110 
111         addExactTerm(booleanQuery, field, String.valueOf(value));
112     }
113 
114     public static void addExactTerm(
115         BooleanQuery booleanQuery, String field, Boolean value) {
116 
117         addExactTerm(booleanQuery, field, String.valueOf(value));
118     }
119 
120     public static void addExactTerm(
121         BooleanQuery booleanQuery, String field, double value) {
122 
123         addExactTerm(booleanQuery, field, String.valueOf(value));
124     }
125 
126     public static void addExactTerm(
127         BooleanQuery booleanQuery, String field, Double value) {
128 
129         addExactTerm(booleanQuery, field, String.valueOf(value));
130     }
131 
132     public static void addExactTerm(
133         BooleanQuery booleanQuery, String field, int value) {
134 
135         addExactTerm(booleanQuery, field, String.valueOf(value));
136     }
137 
138     public static void addExactTerm(
139         BooleanQuery booleanQuery, String field, Integer value) {
140 
141         addExactTerm(booleanQuery, field, String.valueOf(value));
142     }
143 
144     public static void addExactTerm(
145         BooleanQuery booleanQuery, String field, long value) {
146 
147         addExactTerm(booleanQuery, field, String.valueOf(value));
148     }
149 
150     public static void addExactTerm(
151         BooleanQuery booleanQuery, String field, Long value) {
152 
153         addExactTerm(booleanQuery, field, String.valueOf(value));
154     }
155 
156     public static void addExactTerm(
157         BooleanQuery booleanQuery, String field, short value) {
158 
159         addExactTerm(booleanQuery, field, String.valueOf(value));
160     }
161 
162     public static void addExactTerm(
163         BooleanQuery booleanQuery, String field, Short value) {
164 
165         addExactTerm(booleanQuery, field, String.valueOf(value));
166     }
167 
168     public static void addExactTerm(
169         BooleanQuery booleanQuery, String field, String value) {
170 
171         //text = KeywordsUtil.escape(value);
172 
173         Query query = new TermQuery(new Term(field, value));
174 
175         booleanQuery.add(query, BooleanClause.Occur.SHOULD);
176     }
177 
178     public static void addRequiredTerm(
179         BooleanQuery booleanQuery, String field, boolean value) {
180 
181         addRequiredTerm(booleanQuery, field, String.valueOf(value));
182     }
183 
184     public static void addRequiredTerm(
185         BooleanQuery booleanQuery, String field, Boolean value) {
186 
187         addRequiredTerm(booleanQuery, field, String.valueOf(value));
188     }
189 
190     public static void addRequiredTerm(
191         BooleanQuery booleanQuery, String field, double value) {
192 
193         addRequiredTerm(booleanQuery, field, String.valueOf(value));
194     }
195 
196     public static void addRequiredTerm(
197         BooleanQuery booleanQuery, String field, Double value) {
198 
199         addRequiredTerm(booleanQuery, field, String.valueOf(value));
200     }
201 
202     public static void addRequiredTerm(
203         BooleanQuery booleanQuery, String field, int value) {
204 
205         addRequiredTerm(booleanQuery, field, String.valueOf(value));
206     }
207 
208     public static void addRequiredTerm(
209         BooleanQuery booleanQuery, String field, Integer value) {
210 
211         addRequiredTerm(booleanQuery, field, String.valueOf(value));
212     }
213 
214     public static void addRequiredTerm(
215         BooleanQuery booleanQuery, String field, long value) {
216 
217         addRequiredTerm(booleanQuery, field, String.valueOf(value));
218     }
219 
220     public static void addRequiredTerm(
221         BooleanQuery booleanQuery, String field, Long value) {
222 
223         addRequiredTerm(booleanQuery, field, String.valueOf(value));
224     }
225 
226     public static void addRequiredTerm(
227         BooleanQuery booleanQuery, String field, short value) {
228 
229         addRequiredTerm(booleanQuery, field, String.valueOf(value));
230     }
231 
232     public static void addRequiredTerm(
233         BooleanQuery booleanQuery, String field, Short value) {
234 
235         addRequiredTerm(booleanQuery, field, String.valueOf(value));
236     }
237 
238     public static void addRequiredTerm(
239         BooleanQuery booleanQuery, String field, String value) {
240 
241         addRequiredTerm(booleanQuery, field, value, false);
242     }
243 
244     public static void addRequiredTerm(
245         BooleanQuery booleanQuery, String field, String value, boolean like) {
246 
247         if (like) {
248             value = StringUtil.replace(
249                 value, StringPool.PERCENT, StringPool.STAR);
250 
251             value = value.toLowerCase();
252 
253             WildcardQuery wildcardQuery = new WildcardQuery(
254                 new Term(field, value));
255 
256             booleanQuery.add(wildcardQuery, BooleanClause.Occur.MUST);
257         }
258         else {
259             //text = KeywordsUtil.escape(value);
260 
261             Term term = new Term(field, value);
262             TermQuery termQuery = new TermQuery(term);
263 
264             booleanQuery.add(termQuery, BooleanClause.Occur.MUST);
265         }
266     }
267 
268     public static void addTerm(
269             BooleanQuery booleanQuery, String field, long value)
270         throws ParseException {
271 
272         addTerm(booleanQuery, field, String.valueOf(value));
273     }
274 
275     public static void addTerm(
276             BooleanQuery booleanQuery, String field, String value)
277         throws ParseException {
278 
279         addTerm(booleanQuery, field, value, false);
280     }
281 
282     public static void addTerm(
283             BooleanQuery booleanQuery, String field, String value,
284             boolean like)
285         throws ParseException {
286 
287         if (Validator.isNull(value)) {
288             return;
289         }
290 
291         if (like) {
292             value = value.toLowerCase();
293 
294             StringBuilder sb = new StringBuilder();
295 
296             sb.append(StringPool.STAR);
297             sb.append(value);
298             sb.append(StringPool.STAR);
299 
300             WildcardQuery wildcardQuery = new WildcardQuery(
301                 new Term(field, sb.toString()));
302 
303             booleanQuery.add(wildcardQuery, BooleanClause.Occur.SHOULD);
304         }
305         else {
306             QueryParser queryParser = new QueryParser(
307                 field, LuceneUtil.getAnalyzer());
308 
309             try {
310                 Query query = queryParser.parse(value);
311 
312                 booleanQuery.add(query, BooleanClause.Occur.SHOULD);
313             }
314             catch (ParseException pe) {
315                 if (_log.isDebugEnabled()) {
316                     _log.debug(
317                         "ParseException thrown, reverting to literal search",
318                         pe);
319                 }
320 
321                 value = KeywordsUtil.escape(value);
322 
323                 Query query = queryParser.parse(value);
324 
325                 booleanQuery.add(query, BooleanClause.Occur.SHOULD);
326             }
327         }
328     }
329 
330     public static void checkLuceneDir(long companyId) {
331         if (SearchEngineUtil.isIndexReadOnly()) {
332             return;
333         }
334 
335         Directory luceneDir = LuceneUtil.getLuceneDir(companyId);
336 
337         try {
338 
339             // LEP-6078
340 
341             if (luceneDir.fileExists("write.lock")) {
342                 luceneDir.deleteFile("write.lock");
343             }
344         }
345         catch (IOException ioe) {
346             _log.error("Unable to clear write lock", ioe);
347         }
348 
349         IndexWriter writer = null;
350 
351         // Lucene does not properly release its lock on the index when
352         // IndexWriter throws an exception
353 
354         try {
355             if (luceneDir.fileExists("segments.gen")) {
356                 writer = new IndexWriter(
357                     luceneDir, LuceneUtil.getAnalyzer(), false);
358             }
359             else {
360                 writer = new IndexWriter(
361                     luceneDir, LuceneUtil.getAnalyzer(), true);
362             }
363         }
364         catch (IOException ioe) {
365             _log.error("Check Lucene directory failed for " + companyId, ioe);
366         }
367         finally {
368             if (writer != null) {
369                 try {
370                     writer.close();
371                 }
372                 catch (IOException ioe) {
373                     _log.error(ioe);
374                 }
375             }
376         }
377     }
378 
379     public static void delete(long companyId) {
380         _instance._delete(companyId);
381     }
382 
383     public static void deleteDocuments(long companyId, Term term)
384         throws IOException {
385 
386         try {
387             _instance._sharedWriter.deleteDocuments(companyId, term);
388         }
389         catch (InterruptedException ie) {
390             _log.error(ie);
391         }
392     }
393 
394     public static Analyzer getAnalyzer() {
395         return _instance._getAnalyzer();
396     }
397 
398     public static FSDirectory getDirectory(String path, boolean create)
399         throws IOException {
400 
401         return FSDirectory.getDirectory(path, false);
402     }
403 
404     public static Directory getLuceneDir(long companyId) {
405         return _instance._getLuceneDir(companyId);
406     }
407 
408     public static IndexReader getReader(long companyId) throws IOException {
409         return IndexReader.open(getLuceneDir(companyId));
410     }
411 
412     public static IndexSearcher getSearcher(long companyId)
413         throws IOException {
414 
415         return new IndexSearcher(getLuceneDir(companyId));
416     }
417 
418     public static String[] getQueryTerms(Query query) {
419         String[] fieldNames = new String[] {
420             Field.CONTENT, Field.DESCRIPTION, Field.PROPERTIES, Field.TITLE,
421             Field.USER_NAME
422         };
423 
424         WeightedTerm[] weightedTerms = null;
425 
426         for (String fieldName : fieldNames) {
427             weightedTerms = QueryTermExtractor.getTerms(
428                 query, false, fieldName);
429 
430             if (weightedTerms.length > 0) {
431                 break;
432             }
433         }
434 
435         Set<String> queryTerms = new HashSet<String>();
436 
437         for (WeightedTerm weightedTerm : weightedTerms) {
438             queryTerms.add(weightedTerm.getTerm());
439         }
440 
441         return queryTerms.toArray(new String[queryTerms.size()]);
442     }
443 
444     public static String getSnippet(Query query, String field, String s)
445         throws IOException {
446 
447         return getSnippet(
448             query, field, s, 3, 80, "...", StringPool.BLANK, StringPool.BLANK);
449     }
450 
451     public static String getSnippet(
452             Query query, String field, String s, int maxNumFragments,
453             int fragmentLength, String fragmentSuffix, String preTag,
454             String postTag)
455         throws IOException {
456 
457         SimpleHTMLFormatter simpleHTMLFormatter = new SimpleHTMLFormatter(
458             preTag, postTag);
459 
460         QueryScorer queryScorer = new QueryScorer(query, field);
461 
462         Highlighter highlighter = new Highlighter(
463             simpleHTMLFormatter, queryScorer);
464 
465         highlighter.setTextFragmenter(new SimpleFragmenter(fragmentLength));
466 
467         TokenStream tokenStream = LuceneUtil.getAnalyzer().tokenStream(
468             field, new StringReader(s));
469 
470         String snippet = highlighter.getBestFragments(
471             tokenStream, s, maxNumFragments, fragmentSuffix);
472 
473         if (Validator.isNotNull(snippet) &&
474             !StringUtil.endsWith(snippet, fragmentSuffix)) {
475 
476             snippet = snippet + fragmentSuffix;
477         }
478 
479         return snippet;
480     }
481 
482     public static IndexWriter getWriter(long companyId) throws IOException {
483         return getWriter(companyId, false);
484     }
485 
486     public static IndexWriter getWriter(long companyId, boolean create)
487         throws IOException {
488 
489         return _instance._sharedWriter.getWriter(companyId, create);
490     }
491 
492     public static void releaseLock(long companyId) {
493         _instance._sharedWriter.releaseLock(companyId);
494     }
495 
496     public static void write(long companyId) {
497         _instance._sharedWriter.write(companyId);
498     }
499 
500     public static void write(IndexWriter writer) throws IOException {
501         _instance._sharedWriter.write(writer);
502     }
503 
504     private LuceneUtil() {
505         String analyzerName = PropsUtil.get(PropsKeys.LUCENE_ANALYZER);
506 
507         if (Validator.isNotNull(analyzerName)) {
508             try {
509                 _analyzerClass = Class.forName(analyzerName);
510             }
511             catch (Exception e) {
512                 _log.error(e);
513             }
514         }
515 
516         // Dialect
517 
518         if (PropsValues.LUCENE_STORE_TYPE.equals(_LUCENE_STORE_TYPE_JDBC)) {
519             Connection con = null;
520 
521             try {
522                 con = DataAccess.getConnection();
523 
524                 String url = con.getMetaData().getURL();
525 
526                 int x = url.indexOf(":");
527                 int y = url.indexOf(":", x + 1);
528 
529                 String urlPrefix = url.substring(x + 1, y);
530 
531                 String dialectClass = PropsUtil.get(
532                     PropsKeys.LUCENE_STORE_JDBC_DIALECT + urlPrefix);
533 
534                 if (dialectClass != null) {
535                     if (_log.isDebugEnabled()) {
536                         _log.debug("JDBC class implementation " + dialectClass);
537                     }
538                 }
539                 else {
540                     if (_log.isDebugEnabled()) {
541                         _log.debug("JDBC class implementation is null");
542                     }
543                 }
544 
545                 if (dialectClass != null) {
546                     _dialect =
547                         (Dialect)Class.forName(dialectClass).newInstance();
548                 }
549             }
550             catch (Exception e) {
551                 _log.error(e);
552             }
553             finally{
554                 DataAccess.cleanUp(con);
555             }
556 
557             if (_dialect == null) {
558                 _log.error("No JDBC dialect found");
559             }
560         }
561     }
562 
563     private void _delete(long companyId) {
564         if (SearchEngineUtil.isIndexReadOnly()) {
565             return;
566         }
567 
568         if (_log.isDebugEnabled()) {
569             _log.debug("Lucene store type " + PropsValues.LUCENE_STORE_TYPE);
570         }
571 
572         if (PropsValues.LUCENE_STORE_TYPE.equals(_LUCENE_STORE_TYPE_FILE)) {
573             _deleteFile(companyId);
574         }
575         else if (PropsValues.LUCENE_STORE_TYPE.equals(
576                     _LUCENE_STORE_TYPE_JDBC)) {
577 
578             _deleteJdbc(companyId);
579         }
580         else if (PropsValues.LUCENE_STORE_TYPE.equals(_LUCENE_STORE_TYPE_RAM)) {
581             _deleteRam(companyId);
582         }
583         else {
584             throw new RuntimeException(
585                 "Invalid store type " + PropsValues.LUCENE_STORE_TYPE);
586         }
587     }
588 
589     private void _deleteFile(long companyId) {
590         String path = _getPath(companyId);
591 
592         try {
593             Directory directory = getDirectory(path, false);
594 
595             directory.close();
596         }
597         catch (Exception e) {
598             if (_log.isWarnEnabled()) {
599                 _log.warn("Could not close directory " + path);
600             }
601         }
602 
603         FileUtil.deltree(path);
604     }
605 
606     private void _deleteJdbc(long companyId) {
607         String tableName = _getTableName(companyId);
608 
609         try {
610             Directory directory = _jdbcDirectories.remove(tableName);
611 
612             if (directory != null) {
613                 directory.close();
614             }
615         }
616         catch (Exception e) {
617             if (_log.isWarnEnabled()) {
618                 _log.warn("Could not close directory " + tableName);
619             }
620         }
621 
622         Connection con = null;
623         Statement s = null;
624 
625         try {
626             con = DataAccess.getConnection();
627 
628             s = con.createStatement();
629 
630             s.executeUpdate("DELETE FROM " + tableName);
631         }
632         catch (Exception e) {
633             if (_log.isWarnEnabled()) {
634                 _log.warn("Could not truncate " + tableName);
635             }
636         }
637         finally {
638             DataAccess.cleanUp(con, s);
639         }
640     }
641 
642     private void _deleteRam(long companyId) {
643     }
644 
645     private Analyzer _getAnalyzer() {
646         try {
647             return (Analyzer)_analyzerClass.newInstance();
648         }
649         catch (Exception e) {
650             throw new RuntimeException(e);
651         }
652     }
653 
654     private Directory _getLuceneDir(long companyId) {
655         if (_log.isDebugEnabled()) {
656             _log.debug("Lucene store type " + PropsValues.LUCENE_STORE_TYPE);
657         }
658 
659         if (PropsValues.LUCENE_STORE_TYPE.equals(_LUCENE_STORE_TYPE_FILE)) {
660             return _getLuceneDirFile(companyId);
661         }
662         else if (PropsValues.LUCENE_STORE_TYPE.equals(
663                     _LUCENE_STORE_TYPE_JDBC)) {
664 
665             return _getLuceneDirJdbc(companyId);
666         }
667         else if (PropsValues.LUCENE_STORE_TYPE.equals(_LUCENE_STORE_TYPE_RAM)) {
668             return _getLuceneDirRam(companyId);
669         }
670         else {
671             throw new RuntimeException(
672                 "Invalid store type " + PropsValues.LUCENE_STORE_TYPE);
673         }
674     }
675 
676     private Directory _getLuceneDirFile(long companyId) {
677         Directory directory = null;
678 
679         String path = _getPath(companyId);
680 
681         try {
682             directory = getDirectory(path, false);
683         }
684         catch (IOException ioe1) {
685             try {
686                 if (directory != null) {
687                     directory.close();
688                 }
689 
690                 directory = getDirectory(path, true);
691             }
692             catch (IOException ioe2) {
693                 throw new RuntimeException(ioe2);
694             }
695         }
696 
697         return directory;
698     }
699 
700     private Directory _getLuceneDirJdbc(long companyId) {
701         JdbcDirectory directory = null;
702 
703         Thread currentThread = Thread.currentThread();
704 
705         ClassLoader contextClassLoader = currentThread.getContextClassLoader();
706 
707         try {
708             currentThread.setContextClassLoader(
709                 PortalClassLoaderUtil.getClassLoader());
710 
711             String tableName = _getTableName(companyId);
712 
713             directory = (JdbcDirectory)_jdbcDirectories.get(tableName);
714 
715             if (directory != null) {
716                 return directory;
717             }
718 
719             try {
720                 DataSource ds = InfrastructureUtil.getDataSource();
721 
722                 directory = new JdbcDirectory(ds, _dialect, tableName);
723 
724                 _jdbcDirectories.put(tableName, directory);
725 
726                 if (!directory.tableExists()) {
727                     directory.create();
728                 }
729             }
730             catch (IOException ioe) {
731                 throw new RuntimeException(ioe);
732             }
733             catch (UnsupportedOperationException uoe) {
734                 if (_log.isWarnEnabled()) {
735                     _log.warn(
736                         "Database doesn't support the ability to check " +
737                             "whether a table exists");
738                 }
739 
740                 _manuallyCreateJdbcDirectory(directory, tableName);
741             }
742         }
743         finally {
744             currentThread.setContextClassLoader(contextClassLoader);
745         }
746 
747         return directory;
748     }
749 
750     private Directory _getLuceneDirRam(long companyId) {
751         String path = _getPath(companyId);
752 
753         Directory directory = _ramDirectories.get(path);
754 
755         if (directory == null) {
756             directory = new RAMDirectory();
757 
758             _ramDirectories.put(path, directory);
759         }
760 
761         return directory;
762     }
763 
764     private String _getPath(long companyId) {
765         StringBuilder sb = new StringBuilder();
766 
767         sb.append(PropsValues.LUCENE_DIR);
768         sb.append(companyId);
769         sb.append(StringPool.SLASH);
770 
771         return sb.toString();
772     }
773 
774     private String _getTableName(long companyId) {
775         return _LUCENE_TABLE_PREFIX + companyId;
776     }
777 
778     private void _manuallyCreateJdbcDirectory(
779         JdbcDirectory directory, String tableName) {
780 
781         // LEP-2181
782 
783         Connection con = null;
784         ResultSet rs = null;
785 
786         try {
787             con = DataAccess.getConnection();
788 
789             // Check if table exists
790 
791             DatabaseMetaData metaData = con.getMetaData();
792 
793             rs = metaData.getTables(null, null, tableName, null);
794 
795             if (!rs.next()) {
796                 JdbcTemplate jdbcTemplate = directory.getJdbcTemplate();
797 
798                 jdbcTemplate.executeUpdate(directory.getTable().sqlCreate());
799 
800                 Class<?> lockClass = directory.getSettings().getLockClass();
801 
802                 JdbcLock jdbcLock = null;
803 
804                 try {
805                     jdbcLock = (JdbcLock)lockClass.newInstance();
806                 }
807                 catch (Exception e) {
808                     throw new JdbcStoreException(
809                         "Failed to create lock class " + lockClass);
810                 }
811 
812                 jdbcLock.initializeDatabase(directory);
813             }
814         }
815         catch (Exception e) {
816             if (_log.isWarnEnabled()) {
817                 _log.warn("Could not create " + tableName);
818             }
819         }
820         finally {
821             DataAccess.cleanUp(con, null, rs);
822         }
823     }
824 
825     private static final String _LUCENE_STORE_TYPE_FILE = "file";
826 
827     private static final String _LUCENE_STORE_TYPE_JDBC = "jdbc";
828 
829     private static final String _LUCENE_STORE_TYPE_RAM = "ram";
830 
831     private static final String _LUCENE_TABLE_PREFIX = "LUCENE_";
832 
833     private static Log _log = LogFactoryUtil.getLog(LuceneUtil.class);
834 
835     private static LuceneUtil _instance = new LuceneUtil();
836 
837     private IndexWriterFactory _sharedWriter = new IndexWriterFactory();
838     private Class<?> _analyzerClass = WhitespaceAnalyzer.class;
839     private Dialect _dialect;
840     private Map<String, Directory> _jdbcDirectories =
841         new ConcurrentHashMap<String, Directory>();
842     private Map<String, Directory> _ramDirectories =
843         new ConcurrentHashMap<String, Directory>();
844 
845 }