org.apache.solr.spelling.FileBasedSpellChecker.java Source code

Introduction

Here is the source code for org.apache.solr.spelling.FileBasedSpellChecker.java

Source

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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 org.apache.solr.spelling;

import java.io.IOException;
import java.io.InputStreamReader;
import java.util.List;

import org.apache.lucene.document.Field;
import org.apache.lucene.index.DirectoryReader;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.index.IndexWriter;
import org.apache.lucene.index.IndexWriterConfig;
import org.apache.lucene.index.LogByteSizeMergePolicy;
import org.apache.lucene.index.LogMergePolicy;
import org.apache.solr.schema.IndexSchema;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import org.apache.lucene.document.Document;
import org.apache.lucene.document.TextField;
import org.apache.lucene.search.spell.HighFrequencyDictionary;
import org.apache.lucene.search.spell.PlainTextDictionary;
import org.apache.lucene.store.RAMDirectory;
import org.apache.solr.common.util.NamedList;
import org.apache.solr.core.SolrCore;
import org.apache.solr.schema.FieldType;
import org.apache.solr.search.SolrIndexSearcher;

/**
 * <p>
 * A spell checker implementation that loads words from a text file (one word per line).
 * </p>
 *
 * @since solr 1.3
 **/
public class FileBasedSpellChecker extends AbstractLuceneSpellChecker {

    private static final Logger log = LoggerFactory.getLogger(FileBasedSpellChecker.class);

    public static final String SOURCE_FILE_CHAR_ENCODING = "characterEncoding";

    private String characterEncoding;
    public static final String WORD_FIELD_NAME = "word";

    @Override
    public String init(NamedList config, SolrCore core) {
        super.init(config, core);
        characterEncoding = (String) config.get(SOURCE_FILE_CHAR_ENCODING);
        return name;
    }

    @Override
    public void build(SolrCore core, SolrIndexSearcher searcher) throws IOException {
        loadExternalFileDictionary(core, searcher);
        spellChecker.clearIndex();
        // TODO: you should be able to specify the IWC params?
        // TODO: if we enable this, codec gets angry since field won't exist in the schema
        // config.setCodec(core.getCodec());
        spellChecker.indexDictionary(dictionary,
                new IndexWriterConfig(core.getSolrConfig().luceneMatchVersion, null), false);
    }

    /**
     * Override to return null, since there is no reader associated with a file based index
     */
    @Override
    protected IndexReader determineReader(IndexReader reader) {
        return null;
    }

    private void loadExternalFileDictionary(SolrCore core, SolrIndexSearcher searcher) {
        try {
            IndexSchema schema = null == searcher ? core.getLatestSchema() : searcher.getSchema();
            // Get the field's analyzer
            if (fieldTypeName != null && schema.getFieldTypeNoEx(fieldTypeName) != null) {
                FieldType fieldType = schema.getFieldTypes().get(fieldTypeName);
                // Do index-time analysis using the given fieldType's analyzer
                RAMDirectory ramDir = new RAMDirectory();

                LogMergePolicy mp = new LogByteSizeMergePolicy();
                mp.setMergeFactor(300);

                IndexWriter writer = new IndexWriter(ramDir,
                        new IndexWriterConfig(core.getSolrConfig().luceneMatchVersion, fieldType.getAnalyzer())
                                .setMaxBufferedDocs(150).setMergePolicy(mp)
                                .setOpenMode(IndexWriterConfig.OpenMode.CREATE)
                // TODO: if we enable this, codec gets angry since field won't exist in the schema
                // .setCodec(core.getCodec())
                );

                List<String> lines = core.getResourceLoader().getLines(sourceLocation, characterEncoding);

                for (String s : lines) {
                    Document d = new Document();
                    d.add(new TextField(WORD_FIELD_NAME, s, Field.Store.NO));
                    writer.addDocument(d);
                }
                writer.forceMerge(1);
                writer.close();

                dictionary = new HighFrequencyDictionary(DirectoryReader.open(ramDir), WORD_FIELD_NAME, 0.0f);
            } else {
                // check if character encoding is defined
                if (characterEncoding == null) {
                    dictionary = new PlainTextDictionary(core.getResourceLoader().openResource(sourceLocation));
                } else {
                    dictionary = new PlainTextDictionary(new InputStreamReader(
                            core.getResourceLoader().openResource(sourceLocation), characterEncoding));
                }
            }

        } catch (IOException e) {
            log.error("Unable to load spellings", e);
        }
    }

    public String getCharacterEncoding() {
        return characterEncoding;
    }
}