EDIT

// $Id$

/**

 * Copyright (C) 2013 EDIT

 * European Distributed Institute of Taxonomy

 * http://www.e-taxonomy.eu

 *

 * The contents of this file are subject to the Mozilla Public License Version 1.1

 * See LICENSE.TXT at the top of this package for the full license terms.

 */

package eu.etaxonomy.cdm.api.service.search;

import java.util.HashMap;

import java.util.Map;

import org.apache.lucene.analysis.Analyzer;

import org.apache.lucene.index.IndexReader;

import org.apache.lucene.queryparser.classic.QueryParser;

import org.hibernate.SessionFactory;

import org.hibernate.search.Search;

import org.hibernate.search.SearchFactory;

import org.hibernate.search.indexes.IndexReaderAccessor;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.stereotype.Component;

import eu.etaxonomy.cdm.model.common.CdmBase;

import eu.etaxonomy.cdm.model.description.DescriptionElementBase;

import eu.etaxonomy.cdm.model.description.TextData;

import eu.etaxonomy.cdm.model.name.NonViralName;

import eu.etaxonomy.cdm.model.name.TaxonNameBase;

import eu.etaxonomy.cdm.model.taxon.Taxon;

import eu.etaxonomy.cdm.model.taxon.TaxonBase;

/**

 * @author a.kohlbecker

 * @date Sep 18, 2013

 *

 */

@Component

public class LuceneIndexToolProviderImpl implements ILuceneIndexToolProvider {

    private final static String DEFAULT_QURERY_FIELD_NAME = "titleCache";

    @Autowired

    private SessionFactory sessionFactory;

    private final Map<Class<? extends CdmBase>, QueryParser> queryParsers = new HashMap<Class<? extends CdmBase>, QueryParser>();

    /**

     * @param sessionfactory

     * @return

     */

    private SearchFactory getCurrentSearchFactory() {

        return Search.getFullTextSession(sessionFactory.getCurrentSession()).getSearchFactory();

    }

    /**

     * TODO the abstract base class DescriptionElementBase can not be used, so

     * we are using an arbitrary subclass to find the DirectoryProvider, future

     * versions of hibernate search my allow using abstract base classes see

     * {@link http://stackoverflow.com/questions/492184/how-do-you-find-all-subclasses-of-a-given-class-in-java}

     *

     * @param type must not be null

     * @return

     */

    protected Class<? extends CdmBase> pushAbstractBaseTypeDown(Class<? extends CdmBase> type) {

        if(type == null) {

            throw new NullPointerException("parameter type must not be null");

        }

        if (type.equals(DescriptionElementBase.class)) {

            return TextData.class;

        }

        if (type.equals(TaxonBase.class)) {

            return Taxon.class;

        }

        if (type.equals(TaxonNameBase.class)) {

            return NonViralName.class;

        }

        return type;

    }

    /* (non-Javadoc)

     * @see eu.etaxonomy.cdm.api.service.search.ILuceneIndexToolProvider#getIndexReaderFor(java.lang.Class)

     */

    @Override

    public IndexReader getIndexReaderFor(Class<? extends CdmBase> clazz) {

        IndexReader reader = getCurrentSearchFactory().getIndexReaderAccessor().open(pushAbstractBaseTypeDown(clazz));

        return reader;

    }

    /* (non-Javadoc)

     * @see eu.etaxonomy.cdm.api.service.search.ILuceneIndexToolProvider#getQueryParserFor(java.lang.Class)

     */

    @Override

    public QueryParser getQueryParserFor(Class<? extends CdmBase> clazz) {

        if(!queryParsers.containsKey(clazz)){

            Analyzer analyzer = getAnalyzerFor(clazz);

            QueryParser parser = new QueryParser(DEFAULT_QURERY_FIELD_NAME, analyzer);

            queryParsers.put(clazz, parser);

        }

        return queryParsers.get(clazz);

    }

    /**

     * <b>WARING</b> This method might return an Analyzer

     * which is not suitable for all fields of the lucene document. This method

     * internally uses the simplified method from {@link {

     * @link org.hibernate.search.SearchFactory#getAnalyzer(Class)}

     *

     * TODO implement method which allows to retrieve the correct Analyzer

     * per document field, this method will have another signature.

     *

     * @return the Analyzer suitable for the lucene index of the given

     *         <code>clazz</code>

     */

    @Override

    public Analyzer getAnalyzerFor(Class<? extends CdmBase> clazz) {

        Analyzer analyzer = getCurrentSearchFactory().getAnalyzer(pushAbstractBaseTypeDown(clazz));

        return analyzer;

    }

    /* (non-Javadoc)

     * @see eu.etaxonomy.cdm.api.service.search.ILuceneIndexToolProvider#getQueryFactoryFor(java.lang.Class)

     */

    @Override

    public QueryFactory newQueryFactoryFor(Class<? extends CdmBase> clazz){

        return new QueryFactory(this, pushAbstractBaseTypeDown(clazz));

    }

    /* (non-Javadoc)

     * @see eu.etaxonomy.cdm.api.service.search.ILuceneIndexToolProvider#getIndexReaderAccessor()

     */

    @Override

    public IndexReaderAccessor getIndexReaderAccessor(){

        return getCurrentSearchFactory().getIndexReaderAccessor();

    }

}