Java tutorial
/* * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. The ASF licenses this file to You * under the Apache License, Version 2.0 (the "License"); you may not * use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. For additional information regarding * copyright in this work, please see the NOTICE file in the top level * directory of this distribution. */ /* Created on Jul 18, 2003 */ package org.apache.roller.weblogger.business.search.operations; import java.io.IOException; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.apache.lucene.index.IndexReader; import org.apache.lucene.index.Term; import org.apache.lucene.queryparser.classic.MultiFieldQueryParser; import org.apache.lucene.queryparser.classic.ParseException; import org.apache.lucene.search.BooleanClause; import org.apache.lucene.search.BooleanQuery; import org.apache.lucene.search.IndexSearcher; import org.apache.lucene.search.Query; import org.apache.lucene.search.Sort; import org.apache.lucene.search.SortField; import org.apache.lucene.search.TermQuery; import org.apache.lucene.search.TopFieldDocs; import org.apache.roller.weblogger.business.search.FieldConstants; import org.apache.roller.weblogger.business.search.IndexManager; import org.apache.roller.weblogger.business.search.IndexManagerImpl; import org.apache.roller.weblogger.business.search.IndexUtil; /** * An operation that searches the index. * * @author Mindaugas Idzelis (min@idzelis.com) */ public class SearchOperation extends ReadFromIndexOperation { // ~ Static fields/initializers // ============================================= private static Log mLogger = LogFactory.getFactory().getInstance(SearchOperation.class); private static String[] SEARCH_FIELDS = new String[] { FieldConstants.CONTENT, FieldConstants.TITLE, FieldConstants.C_CONTENT }; private static Sort SORTER = new Sort(new SortField(FieldConstants.PUBLISHED, SortField.Type.STRING, true)); // ~ Instance fields // ======================================================== private IndexSearcher searcher; private TopFieldDocs searchresults; private String term; private String websiteHandle; private String category; private String locale; private String parseError; // ~ Constructors // =========================================================== /** * Create a new operation that searches the index. */ public SearchOperation(IndexManager mgr) { // TODO: finish moving IndexManager to backend, so this cast is not // needed super((IndexManagerImpl) mgr); } // ~ Methods // ================================================================ public void setTerm(String term) { this.term = term; } /* * (non-Javadoc) * * @see java.lang.Runnable#run() */ public void doRun() { final int docLimit = 500; searchresults = null; searcher = null; try { IndexReader reader = manager.getSharedIndexReader(); searcher = new IndexSearcher(reader); MultiFieldQueryParser multiParser = new MultiFieldQueryParser(FieldConstants.LUCENE_VERSION, SEARCH_FIELDS, IndexManagerImpl.getAnalyzer()); // Make it an AND by default. Comment this out for an or (default) multiParser.setDefaultOperator(MultiFieldQueryParser.Operator.AND); // Create a query object out of our term Query query = multiParser.parse(term); Term tUsername = IndexUtil.getTerm(FieldConstants.WEBSITE_HANDLE, websiteHandle); if (tUsername != null) { BooleanQuery bQuery = new BooleanQuery(); bQuery.add(query, BooleanClause.Occur.MUST); bQuery.add(new TermQuery(tUsername), BooleanClause.Occur.MUST); query = bQuery; } if (category != null) { Term tCategory = new Term(FieldConstants.CATEGORY, category.toLowerCase()); BooleanQuery bQuery = new BooleanQuery(); bQuery.add(query, BooleanClause.Occur.MUST); bQuery.add(new TermQuery(tCategory), BooleanClause.Occur.MUST); query = bQuery; } Term tLocale = IndexUtil.getTerm(FieldConstants.LOCALE, locale); if (tLocale != null) { BooleanQuery bQuery = new BooleanQuery(); bQuery.add(query, BooleanClause.Occur.MUST); bQuery.add(new TermQuery(tLocale), BooleanClause.Occur.MUST); query = bQuery; } searchresults = searcher.search(query, null/* Filter */, docLimit, SORTER); } catch (IOException e) { mLogger.error("Error searching index", e); parseError = e.getMessage(); } catch (ParseException e) { // who cares? parseError = e.getMessage(); } // don't need to close the reader, since we didn't do any writing! } /** * Gets the searcher. * * @return the searcher */ public IndexSearcher getSearcher() { return searcher; } /** * Sets the searcher. * * @param searcher * the new searcher */ public void setSearcher(IndexSearcher searcher) { this.searcher = searcher; } /** * Gets the results. * * @return the results */ public TopFieldDocs getResults() { return searchresults; } /** * Gets the results count. * * @return the results count */ public int getResultsCount() { if (searchresults == null) { return -1; } return searchresults.totalHits; } /** * Gets the parses the error. * * @return the parses the error */ public String getParseError() { return parseError; } /** * Sets the website handle. * * @param websiteHandle * the new website handle */ public void setWebsiteHandle(String websiteHandle) { this.websiteHandle = websiteHandle; } /** * Sets the category. * * @param category * the new category */ public void setCategory(String category) { this.category = category; } /** * Sets the locale. * * @param locale * the new locale */ public void setLocale(String locale) { this.locale = locale; } }