/**
* 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.nutch.analysis.lang;
// Nutch imports
import org.apache.nutch.crawl.CrawlDatum;
import org.apache.nutch.crawl.Inlinks;
import org.apache.nutch.indexer.IndexingFilter;
import org.apache.nutch.indexer.IndexingException;
import org.apache.nutch.indexer.NutchDocument;
import org.apache.nutch.indexer.lucene.LuceneWriter;
import org.apache.hadoop.io.Text;
import org.apache.nutch.parse.Parse;
import org.apache.nutch.metadata.Metadata;
import org.apache.nutch.net.protocols.Response;
// Hadoop imports
import org.apache.hadoop.conf.Configuration;
/**
* An {@link org.apache.nutch.indexer.IndexingFilter} that
* add a <code>lang</code> (language) field to the document.
*
* It tries to find the language of the document by:
* <ul>
* <li>First, checking if {@link HTMLLanguageParser} add some language
* information</li>
* <li>Then, checking if a <code>Content-Language</code> HTTP header can be
* found</li>
* <li>Finaly by analyzing the document content</li>
* </ul>
*
* @author Sami Siren
* @author Jerome Charron
*/
public class LanguageIndexingFilter implements IndexingFilter {
private Configuration conf;
private LanguageIdentifier languageIdentifier;
/**
* Constructs a new Language Indexing Filter.
*/
public LanguageIndexingFilter() {
}
// Inherited JavaDoc
public NutchDocument filter(NutchDocument doc, Parse parse, Text url, CrawlDatum datum, Inlinks inlinks)
throws IndexingException {
// check if LANGUAGE found, possibly put there by HTMLLanguageParser
String lang = parse.getData().getParseMeta().get(Metadata.LANGUAGE);
// check if HTTP-header tels us the language
if (lang == null) {
lang = parse.getData().getContentMeta().get(Response.CONTENT_LANGUAGE);
}
if (lang == null) {
StringBuilder text = new StringBuilder();
/*
* String[] anchors = fo.getAnchors(); for (int i = 0; i < anchors.length;
* i++) { text+=anchors[i] + " "; }
*/
text.append(parse.getData().getTitle())
.append(" ")
.append(parse.getText());
lang = this.languageIdentifier.identify(text);
}
if (lang == null) {
lang = "unknown";
}
doc.add("lang", lang);
return doc;
}
public void addIndexBackendOptions(Configuration conf) {
LuceneWriter.addFieldOptions("lang", LuceneWriter.STORE.YES,
LuceneWriter.INDEX.UNTOKENIZED, conf);
}
public void setConf(Configuration conf) {
this.conf = conf;
this.languageIdentifier = new LanguageIdentifier(conf);
}
public Configuration getConf() {
return this.conf;
}
}