EDIT

/**

 * Copyright (C) 2007 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.persistence.dao.hibernate;

import java.io.IOException;

import java.io.StringReader;

import java.util.Vector;

import org.apache.commons.logging.Log;

import org.apache.commons.logging.LogFactory;

import org.apache.lucene.analysis.Analyzer;

import org.apache.lucene.analysis.Token;

import org.apache.lucene.analysis.TokenStream;

import org.apache.lucene.analysis.standard.StandardAnalyzer;

import org.apache.lucene.index.CorruptIndexException;

import org.apache.lucene.index.IndexReader;

import org.apache.lucene.index.IndexWriterConfig;

import org.apache.lucene.index.Term;

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

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

import org.apache.lucene.search.PhraseQuery;

import org.apache.lucene.search.Query;

import org.apache.lucene.search.TermQuery;

import org.apache.lucene.search.spell.Dictionary;

import org.apache.lucene.search.spell.LuceneDictionary;

import org.apache.lucene.search.spell.SpellChecker;

import org.apache.lucene.store.Directory;

import org.apache.lucene.util.BytesRef;

import org.apache.lucene.util.BytesRefIterator;

import org.hibernate.SessionFactory;

import org.hibernate.search.FullTextSession;

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.orm.hibernate3.support.HibernateDaoSupport;

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

import eu.etaxonomy.cdm.persistence.dao.IAlternativeSpellingSuggestionParser;

/**

 * @author unknown

 *

 * @param <T>

 * @deprecated Use current methods for alternative spelling suggestions. This class is no longer supported

 * after migration to hibernate 4.x.

 */

@Deprecated

public abstract class AlternativeSpellingSuggestionParser<T extends CdmBase>

		extends HibernateDaoSupport

		implements IAlternativeSpellingSuggestionParser {

	private static Log log = LogFactory.getLog(AlternativeSpellingSuggestionParser.class);

	private String defaultField;

	protected Directory directory;

	private final Class<T> type;

	private Class<? extends T> indexedClasses[];

	public AlternativeSpellingSuggestionParser(Class<T> type) {

		this.type = type;

	}

	public void setIndexedClasses(Class<? extends T> indexedClasses[]) {

		this.indexedClasses = indexedClasses;

	}

	public abstract void setDirectory(Directory directory);

	@Autowired

	public void setHibernateSessionFactory(SessionFactory sessionFactory) {

		super.setSessionFactory(sessionFactory);

	}

	public void setDefaultField(String defaultField) {

		this.defaultField = defaultField;

	}

	@Override

    public Query parse(String queryString) throws ParseException {

		QueryParser queryParser = new QueryParser(defaultField, new StandardAnalyzer());

		return queryParser.parse(queryString);

	}

	@Override

    public Query suggest(String queryString) throws ParseException {

		QuerySuggester querySuggester = new QuerySuggester(defaultField, new StandardAnalyzer());

		Query query = querySuggester.parse(queryString);

		return querySuggester.hasSuggestedQuery() ? query : null;

	}

	private class QuerySuggester extends QueryParser {

		private boolean suggestedQuery = false;

		public QuerySuggester(String field, Analyzer analyzer) {

			super(field, analyzer);

		}

		@Override

        protected Query getFieldQuery(String field, String queryText, boolean quoted) throws ParseException {

			// Copied from org.apache.lucene.queryParser.QueryParser

			// replacing construction of TermQuery with call to getTermQuery()

			// which finds close matches.

			TokenStream source;

            source = getAnalyzer().tokenStream(field, new StringReader(queryText));

			Vector<Object> v = new Vector<Object>();

			Token t;

			while (true) {

				try {

					//OLD

//					t = source.next();

					//FIXME this is new after Hibernate 4 migration

					//but completely unchecked and unsure if correct

					//#3344

					boolean it = source.incrementToken();

					t = source.getAttribute(Token.class);

				} catch (IOException e) {

					t = null;

				}

				if (t == null){

					break;

				}

//		OLD		v.addElement(t.termText());

				//FIXME unchecked #3344

				//FIXME #4716  not sure if this implementation equals the old t.term()

                String term = new String(t.buffer(), 0, t.length());

				v.addElement(term);

			}

			try {

				source.close();

			} catch (IOException e) {

				// ignore

			}

			if (v.size() == 0) {

                return null;

            } else if (v.size() == 1) {

                return new TermQuery(getTerm(field, (String) v.elementAt(0)));

            } else {

				PhraseQuery q = new PhraseQuery();

				q.setSlop(getPhraseSlop());

				for (int i = 0; i < v.size(); i++) {

					q.add(getTerm(field, (String) v.elementAt(i)));

				}

				return q;

			}

		}

		private Term getTerm(String field, String queryText) throws ParseException {

			try {

				SpellChecker spellChecker = new SpellChecker(directory);

				if (spellChecker.exist(queryText)) {

					return new Term(field, queryText);

				}

				String[] similarWords = spellChecker.suggestSimilar(queryText, 1);

				if (similarWords.length == 0) {

					return new Term(field, queryText);

				}

				suggestedQuery = true;

				return new Term(field, similarWords[0]);

			} catch (IOException e) {

				throw new ParseException(e.getMessage());

			}

		}

		public boolean hasSuggestedQuery() {

			return suggestedQuery;

		}

	}

	@Override

    public void refresh() {

		FullTextSession fullTextSession = Search.getFullTextSession(getSession());

		SearchFactory searchFactory = fullTextSession.getSearchFactory();

		try {

			SpellChecker spellChecker = new SpellChecker(directory);

			for(Class<? extends T> indexedClass : indexedClasses) {

				//OLD

//				DirectoryProvider<?> directoryProvider = searchFactory.getDirectoryProviders(indexedClass)[0];

//				ReaderProvider readerProvider = searchFactory.getReaderProvider();

				IndexReaderAccessor ira = searchFactory.getIndexReaderAccessor();

//				IndexReader indexReader = ira.open(indexedClass);

				IndexReader indexReader = null;

				try {

					indexReader = ira.open(indexedClass);

//					indexReader = readerProvider.openIndexReader(); //  .openReader(directoryProvider);

					log.debug("Creating new dictionary for words in " + defaultField + " docs " + indexReader.numDocs());

					Dictionary dictionary = new LuceneDictionary(indexReader, defaultField);

					if(log.isDebugEnabled()) {

						BytesRefIterator iterator = dictionary.getEntryIterator();

						BytesRef bytesRef;

						while((bytesRef = iterator.next())  != null) {

							log.debug("Indexing word " + bytesRef);

						}

					}

//					OLD: spellChecker.indexDictionary(dictionary);

					//FIXME preliminary for Hibernate 4 migration see # 3344

					IndexWriterConfig config = new IndexWriterConfig( new StandardAnalyzer());

					boolean fullMerge = true;

					spellChecker.indexDictionary(dictionary, config, fullMerge);

				} catch (CorruptIndexException cie) {

					log.error("Spellings index is corrupted", cie);

				} finally {

					if (indexReader != null) {

//						readerProvider.closeIndexReader(indexReader);

						ira.close(indexReader);

					}

				}

			}

		}catch (IOException ioe) {

			log.error(ioe);

		}

	}

}