/*
* 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.postag;
import java.io.IOException;
import java.io.Reader;
import java.util.logging.Level;
import java.util.logging.Logger;
import opennlp.tools.util.FilterObjectStream;
import opennlp.tools.util.InvalidFormatException;
import opennlp.tools.util.ObjectStream;
import opennlp.tools.util.PlainTextByLineStream;
/**
* A stream filter which reads a sentence per line which contains
* words and tags in word_tag format and outputs a {@link POSSample} objects.
*/
public class WordTagSampleStream extends FilterObjectStream<String, POSSample> {
private static Logger logger = Logger.getLogger(WordTagSampleStream.class.getName());
/**
* Initializes the current instance.
*
* @param sentences reader with sentences
* @throws IOException IOException
*/
public WordTagSampleStream(Reader sentences) throws IOException {
super(new PlainTextByLineStream(sentences));
}
public WordTagSampleStream(ObjectStream<String> sentences) {
super(sentences);
}
/**
* Parses the next sentence and return the next
* {@link POSSample} object.
*
* If an error occurs an empty {@link POSSample} object is returned
* and an warning message is logged. Usually it does not matter if one
* of many sentences is ignored.
*
* TODO: An exception in error case should be thrown.
*/
public POSSample read() throws IOException {
String sentence = samples.read();
if (sentence != null) {
POSSample sample;
try {
sample = POSSample.parse(sentence);
} catch (InvalidFormatException e) {
if (logger.isLoggable(Level.WARNING)) {
logger.warning("Error during parsing, ignoring sentence: " + sentence);
}
sample = new POSSample(new String[]{}, new String[]{});
}
return sample;
}
else {
// sentences stream is exhausted
return null;
}
}
}