com.tamingtext.qa.QuestionQParser.java Source code

Introduction

Here is the source code for com.tamingtext.qa.QuestionQParser.java

Source

/*
 * Copyright 2008-2011 Grant Ingersoll, Thomas Morton and Drew Farris
 *
 *    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.
 * -------------------
 * To purchase or learn more about Taming Text, by Grant Ingersoll, Thomas Morton and Drew Farris, visit
 * http://www.manning.com/ingersoll
 */

package com.tamingtext.qa;

import java.io.IOException;
import java.io.StringReader;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;

import opennlp.tools.cmdline.parser.ParserTool;
import opennlp.tools.parser.Parse;
import opennlp.tools.parser.Parser;

import org.apache.lucene.analysis.Analyzer;
import org.apache.lucene.analysis.TokenStream;
import org.apache.lucene.analysis.tokenattributes.CharTermAttribute;
import org.apache.lucene.index.Term;
import org.apache.lucene.queryParser.ParseException;
import org.apache.lucene.search.Query;
import org.apache.lucene.search.spans.SpanNearQuery;
import org.apache.lucene.search.spans.SpanQuery;
import org.apache.lucene.search.spans.SpanTermQuery;
import org.apache.solr.common.SolrException;
import org.apache.solr.common.SolrException.ErrorCode;
import org.apache.solr.common.params.SolrParams;
import org.apache.solr.request.SolrQueryRequest;
import org.apache.solr.schema.SchemaField;
import org.apache.solr.search.QParser;

/**
 * The QuestionQParser takes in a natural language question and produces a Lucene {@link org.apache.lucene.search.spans.SpanNearQuery}
 *
 */
public class QuestionQParser extends QParser implements QAParams {

    private Parser parser;
    private AnswerTypeClassifier atc;
    private Map<String, String> atm;

    public QuestionQParser(String qstr, SolrParams localParams, SolrParams params, SolrQueryRequest req,
            Parser parser, AnswerTypeClassifier atc, Map<String, String> answerTypeMap) {
        super(qstr, localParams, params, req);
        this.parser = parser;
        this.atc = atc;
        this.atm = answerTypeMap;
    }

    @Override
    public Query parse() throws ParseException {

        //<start id="qqp.parse"/>
        Parse parse = ParserTool.parseLine(qstr, parser, 1)[0];//<co id="qqp.parseLine"/>
        /*
        <calloutlist>
            <callout arearefs="qqp.parseLine"><para>Parse the question using the <classname>TreebankParser</classname>.  The resulting <classname>Parse</classname> object can then be utilized by the classifier to determine the Answer Type.</para></callout>
        </calloutlist>
        */
        //<end id="qqp.parse"/>
        //<start id="qqp.answerType"/>
        String type = atc.computeAnswerType(parse);
        String mt = atm.get(type);
        //<end id="qqp.answerType"/>
        String field = params.get(QUERY_FIELD);
        SchemaField sp = req.getSchema().getFieldOrNull(field);
        if (sp == null) {
            throw new SolrException(ErrorCode.SERVER_ERROR, "Undefined field: " + field);
        }
        //<start id="qqp.query"/>
        List<SpanQuery> sql = new ArrayList<SpanQuery>();
        if (mt != null) {//<co id="qqp.handleAT"/>
            String[] parts = mt.split("\\|");
            if (parts.length == 1) {
                sql.add(new SpanTermQuery(new Term(field, mt.toLowerCase())));
            } else {
                for (int pi = 0; pi < parts.length; pi++) {
                    sql.add(new SpanTermQuery(new Term(field, parts[pi])));
                }
            }
        }
        try {
            Analyzer analyzer = sp.getType().getQueryAnalyzer();
            TokenStream ts = analyzer.tokenStream(field, new StringReader(qstr));
            while (ts.incrementToken()) {//<co id="qqp.addTerms"/>
                String term = ((CharTermAttribute) ts.getAttribute(CharTermAttribute.class)).toString();
                sql.add(new SpanTermQuery(new Term(field, term)));
            }
        } catch (IOException e) {
            throw new ParseException(e.getLocalizedMessage());
        }
        return new SpanNearQuery(sql.toArray(new SpanQuery[sql.size()]), params.getInt(QAParams.SLOP, 10), true);//<co id="qqp.spanNear"/>
        /*
        <calloutlist>
            <callout arearefs="qqp.handleAT"><para>Add the AnswerType to the query</para></callout>
            <callout arearefs="qqp.addTerms"><para>Add the original query terms to the query</para></callout>
            <callout arearefs="qqp.spanNear"><para>Query the index looking for all of the parts near each other</para></callout>
        </calloutlist>
        */
        //<end id="qqp.query"/>
    }

}