edu.ur.ir.institution.service.DefaultInstitutionalCollectionSearchService.java Source code

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Here is the source code for edu.ur.ir.institution.service.DefaultInstitutionalCollectionSearchService.java

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/**  
Copyright 2008 University of Rochester
    
Licensed 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.
*/

package edu.ur.ir.institution.service;

import java.io.File;
import java.io.IOException;
import java.util.ArrayList;

import org.apache.log4j.Logger;
import org.apache.lucene.analysis.Analyzer;
import org.apache.lucene.document.Document;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.queryParser.MultiFieldQueryParser;
import org.apache.lucene.queryParser.QueryParser;
import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.search.Query;
import org.apache.lucene.search.TopDocs;
import org.apache.lucene.store.FSDirectory;
import org.apache.lucene.util.NumericUtils;
import org.apache.lucene.util.Version;

import edu.ur.ir.SearchHelper;
import edu.ur.ir.SearchResults;
import edu.ur.ir.institution.InstitutionalCollection;
import edu.ur.ir.institution.InstitutionalCollectionSearchService;
import edu.ur.ir.institution.InstitutionalCollectionService;

/**
 * Default Service to search for institutional collections.
 * 
 * @author Nathan Sarr
 *
 */
public class DefaultInstitutionalCollectionSearchService implements InstitutionalCollectionSearchService {

    /** eclipse generated id */
    private static final long serialVersionUID = -3343751267039009528L;

    /** Fields to be searched   */
    private String[] fields = { DefaultInstitutionalCollectionIndexService.DESCRIPTION,
            DefaultInstitutionalCollectionIndexService.NAME };

    /** Service to deal with institutional collection information. */
    private InstitutionalCollectionService institutionalCollectionService;

    /** Analyzer for dealing with analyzing the search */
    private transient Analyzer analyzer;

    /**  Get the logger for this class */
    private static final Logger log = Logger.getLogger(DefaultInstitutionalCollectionSearchService.class);

    /**
     * Returns search results for institutional collections.
     * 
     * @param institutionalCollectionIndexFolder - folder for the institutional collections
     * @param query - query to execute
     * @param offset - offset to start at
     * @param numResults - number of results.
     * 
     * @return - set of users found for the query.
     */
    public SearchResults<InstitutionalCollection> search(File institutionalCollectionIndexFolder, String query,
            int offset, int numResults) {
        SearchResults<InstitutionalCollection> searchResults = new SearchResults<InstitutionalCollection>();
        searchResults.setOriginalQuery(query);
        query = SearchHelper.prepareMainSearchString(query, true);
        ArrayList<InstitutionalCollection> collections = new ArrayList<InstitutionalCollection>();
        if (log.isDebugEnabled()) {
            log.debug("User search results executing query " + query + " on index "
                    + institutionalCollectionIndexFolder.getAbsolutePath());
        }

        IndexSearcher searcher = null;
        IndexReader reader = null;
        try {
            FSDirectory directory = FSDirectory.open(institutionalCollectionIndexFolder);
            reader = IndexReader.open(directory, true);
            searcher = new IndexSearcher(reader);

            QueryParser parser = new MultiFieldQueryParser(Version.LUCENE_35, fields, analyzer);
            parser.setDefaultOperator(QueryParser.AND_OPERATOR);

            Query luceneQuery = parser.parse(query);
            TopDocs hits = searcher.search(luceneQuery, 1000);

            searchResults.setTotalHits(hits.totalHits);

            int position = offset;
            int addedResults = 0;
            while (hits.totalHits > position && (addedResults < numResults)) {
                if (log.isDebugEnabled()) {
                    log.debug(" adding document at position " + position);

                }

                Document d = searcher.doc(hits.scoreDocs[position].doc);

                Long collectionId = NumericUtils
                        .prefixCodedToLong(d.get(DefaultInstitutionalCollectionIndexService.ID));
                ;
                if (log.isDebugEnabled()) {
                    log.debug("collection id = " + collectionId);
                }

                InstitutionalCollection collection = institutionalCollectionService.getCollection(collectionId,
                        false);
                collections.add(collection);
                addedResults += 1;
                position += 1;
            }
        } catch (Exception e) {
            log.error(e);
        } finally {
            if (searcher != null) {
                try {
                    searcher.close();
                } catch (IOException e) {
                    log.error("the searcher could not be closed", e);
                }
            }
            if (reader != null) {
                try {
                    reader.close();
                } catch (IOException e) {
                    log.error("the reader could not be closed", e);
                }
            }
        }
        searchResults.setObjects(collections);
        return searchResults;
    }

    /**
     * Set the institutional collection service.
     * 
     * @param institutionalCollectionService
     */
    public void setInstitutionalCollectionService(InstitutionalCollectionService institutionalCollectionService) {
        this.institutionalCollectionService = institutionalCollectionService;
    }

    /**
     * Set the analyzer.
     * 
     * @param analyzer
     */
    public void setAnalyzer(Analyzer analyzer) {
        this.analyzer = analyzer;
    }

}