eu.europeana.querylog.learn.query.BM25FSolrResults.java Source code

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Here is the source code for eu.europeana.querylog.learn.query.BM25FSolrResults.java

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/**
 *  Copyright 2014 Diego Ceccarelli
 *
 *  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 eu.europeana.querylog.learn.query;

import it.cnr.isti.hpc.property.ProjectProperties;

import java.util.ArrayList;
import java.util.List;

import org.apache.solr.client.solrj.SolrQuery;
import org.apache.solr.client.solrj.SolrServerException;
import org.apache.solr.client.solrj.impl.HttpSolrServer;
import org.apache.solr.client.solrj.response.QueryResponse;
import org.apache.solr.common.SolrDocument;
import org.apache.solr.common.SolrDocumentList;

/**
 * Implements a Solr Server that answers a query using the BM25F ranking
 * function.
 * 
 * @author Diego Ceccarelli <diego.ceccarelli@isti.cnr.it>
 * 
 *         Created on Mar 11, 2014
 */
public class BM25FSolrResults implements SolrResultsRetriever {

    private static final String PREFIX = "http://europeana.eu/portal/record";
    private static HttpSolrServer server;
    private static ProjectProperties properties = new ProjectProperties(BM25FSolrResults.class);

    public BM25FSolrResults() {
        if (server == null)
            server = new HttpSolrServer(properties.get("bm25f.request.handler"));
    }

    public List<String> results(String q, int n) {
        SolrQuery query = new SolrQuery(q);
        query.setRows(n);
        query.setFields("europeana_id");
        return retrieveTopDocuments(query);
    }

    @Override
    public List<String> results(SolrQuery query, int n) {
        query.setRows(n);
        query.setFields("europeana_id");
        return retrieveTopDocuments(query);
    }

    public List<String> retrieveTopDocuments(SolrQuery solrQuery) {
        List<String> results = new ArrayList<String>();
        solrQuery.set("defType", "bm25f");
        QueryResponse qr = null;
        try {
            qr = server.query(solrQuery);
        } catch (SolrServerException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        SolrDocumentList res = qr.getResults();
        for (SolrDocument solrDoc : res) {
            String doc = (String) solrDoc.getFieldValue("europeana_id");
            results.add(String.format("%s%s.html", PREFIX, doc));
        }

        return results;
    }

    public static void main(String[] args) {
        BM25FSolrResults producer = new BM25FSolrResults();

        for (String q : producer.results("picasso", 10)) {
            System.out.println(q);
        }
    }

    @Override
    public String getName() {
        return "bm25f";
    }
}