org.neo4j.index.lucene.LuceneFulltextIndexService.java Source code

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Here is the source code for org.neo4j.index.lucene.LuceneFulltextIndexService.java

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/**
 * Copyright (c) 2002-2010 "Neo Technology,"
 * Network Engine for Objects in Lund AB [http://neotechnology.com]
 *
 * This file is part of Neo4j.
 *
 * Neo4j is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as
 * published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 */

package org.neo4j.index.lucene;

import java.io.IOException;
import java.io.StringReader;

import org.apache.lucene.analysis.TokenStream;
import org.apache.lucene.analysis.tokenattributes.TermAttribute;
import org.apache.lucene.index.Term;
import org.apache.lucene.search.BooleanClause.Occur;
import org.apache.lucene.search.BooleanQuery;
import org.apache.lucene.search.Query;
import org.apache.lucene.search.TermQuery;
import org.neo4j.graphdb.GraphDatabaseService;
import org.neo4j.graphdb.Node;
import org.neo4j.index.IndexHits;

/**
 * A {@link LuceneIndexService} which indexes the values with fulltext indexing.
 * Fulltext means that the indexing process takes the values you throw in and
 * tokenizes those into words so that you can query for those individual words
 * in {@link #getNodes(String, Object)}. Also queries are case-insensitive.
 * 
 * It stores more data per Lucene entry to make this possible. This makes it
 * incompatible with {@link LuceneIndexService} so it has got its own XA
 * resource ID. This means that you can have one {@link LuceneIndexService} and
 * one {@link LuceneFulltextIndexService} for a {@link GraphDatabaseService}.
 * 
 * See more information at
 * http://wiki.neo4j.org/content/Indexing_with_IndexService#Fulltext_indexing
 */
public class LuceneFulltextIndexService extends LuceneIndexService {
    protected static final String DOC_INDEX_SOURCE_KEY = "index_source";
    protected static final String FULLTEXT_DIR_NAME_POSTFIX = "-fulltext";

    /**
     * @param graphDb the {@link GraphDatabaseService} to use.
     */
    public LuceneFulltextIndexService(GraphDatabaseService graphDb) {
        super(graphDb);
    }

    @Override
    protected Class<? extends LuceneDataSource> getDataSourceClass() {
        return LuceneFulltextDataSource.class;
    }

    @Override
    protected String getDirName() {
        return super.getDirName() + FULLTEXT_DIR_NAME_POSTFIX;
    }

    @Override
    protected byte[] getXaResourceId() {
        return "262374".getBytes();
    }

    /**
     * Since this is a "fulltext" index it changes the contract of this method
     * slightly. It treats the {@code value} more like a query in than you can
     * query for individual words in your indexed values.
     * 
     * So if you've indexed node (1) with value "Andy Wachowski" and node (2)
     * with "Larry Wachowski" you can expect this behaviour if you query for:
     * 
     * <ul>
     * <li>"addy" --> (1)</li>
     * <li>"Andy" --> (1)</li>
     * <li>"wachowski" --> (1), (2)</li>
     * <li>"andy larry" --></li>
     * <li>"larry Wachowski" --> (2)</li>
     * <li>"wachowski Andy" --> (1)</li>
     * </ul>
     */
    @Override
    public IndexHits<Node> getNodes(String key, Object value) {
        return super.getNodes(key, value);
    }

    /**
     * Does a {@link #getNodes(String, Object)} using exact matching, so that
     * it for this call behaves like {@link LuceneIndexService}.
     * @param key the key.
     * @param value the query.
     * @return the result of the query.
     */
    @Override
    public IndexHits<Node> getNodesExactMatch(String key, Object value) {
        return getNodes(key, value, MatchingType.EXACT, null);
    }

    @Override
    public Node getSingleNodeExactMatch(String key, Object value) {
        return getSingleNode(key, value, MatchingType.EXACT);
    }

    @Override
    protected Query formQuery(String key, Object value, Object matching) {
        if (matching == MatchingType.EXACT) {
            return new TermQuery(new Term(DOC_INDEX_SOURCE_KEY, value.toString()));
        }

        TokenStream stream = LuceneFulltextDataSource.LOWER_CASE_WHITESPACE_ANALYZER.tokenStream(DOC_INDEX_KEY,
                new StringReader(value.toString().toLowerCase()));
        BooleanQuery booleanQuery = new BooleanQuery();
        try {
            while (stream.incrementToken()) {
                String term = stream.getAttribute(TermAttribute.class).term();
                booleanQuery.add(new TermQuery(new Term(DOC_INDEX_KEY, term)), Occur.MUST);
            }
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
        return booleanQuery;
    }

    @Override
    public void enableCache(String key, int maxNumberOfCachedEntries) {
        // For now, or is it just not feasable
        throw new UnsupportedOperationException();
    }

    static enum MatchingType {
        DEFAULT, EXACT
    }
}