/*
* 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 opennlp.tools.formats;
import java.io.IOException;
import java.io.InputStream;
import java.util.HashMap;
import java.util.Map;
import opennlp.tools.doccat.DocumentSample;
import opennlp.tools.tokenize.SimpleTokenizer;
import opennlp.tools.util.FilterObjectStream;
import opennlp.tools.util.PlainTextByLineStream;
/**
* Stream filter to produce document samples out of a Leipzig sentences.txt file.
* In the Leipzig corpus the encoding of the various senences.txt file is defined by
* the language. The language must be specified to produce the category tags and is used
* to determine the correct input encoding.
* <p>
* The input text is tokenized with the {@link SimpleTokenizer}. The input text classified
* by the language model must also be tokenized by the {@link SimpleTokenizer} to produce
* exactly the same tokenization during testing and training.
*/
public class LeipzigDoccatSampleStream extends
FilterObjectStream<String, DocumentSample> {
private final String language;
private final int sentencesPerDocument;
/**
* Creates a new LeipzigDoccatSampleStream with the specified parameters.
*
* @param language the Leipzig input sentences.txt file
* @param sentencesPerDocument the number of sentences which should be grouped into once {@link DocumentSample}
* @param in the InputStream pointing to the contents of the sentences.txt input file
*/
LeipzigDoccatSampleStream(String language, int sentencesPerDocument,
InputStream in) throws IOException {
super(new PlainTextByLineStream(in, "UTF-8"));
this.language = language;
this.sentencesPerDocument = sentencesPerDocument;
}
public DocumentSample read() throws IOException {
int count = 0;
StringBuilder sampleText = new StringBuilder();
String line;
while (count < sentencesPerDocument && (line = samples.read()) != null) {
String tokens[] = SimpleTokenizer.INSTANCE.tokenize(line);
if (tokens.length == 0) {
throw new IOException("Empty lines are not allowed!");
}
// Always skip first token, that is the sentence number!
for (int i = 1; i < tokens.length; i++) {
sampleText.append(tokens[i]);
sampleText.append(' ');
}
count++;
}
if (sampleText.length() > 0) {
return new DocumentSample(language, sampleText.toString());
}
return null;
}
}