opennlp.tools.sentdetect.EmptyLinePreprocessorStream Maven / Gradle / Ivy
/*
* 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.sentdetect;
import java.io.IOException;
import opennlp.tools.util.FilterObjectStream;
import opennlp.tools.util.ObjectStream;
/**
* Stream to to clean up empty lines for empty line separated document streams.
*
* - Skips empty line at training data start
* - Transforms multiple empty lines in a row into one
* - Replaces white space lines with empty lines
* - TODO: Terminates last document with empty line if it is missing
*
* This stream should be used by the components that mark empty lines to mark document boundaries.
*
* Note:
* This class is not thread safe.
* Do not use this class, internal use only!
*/
public class EmptyLinePreprocessorStream extends FilterObjectStream {
private boolean lastLineWasEmpty = true;
public EmptyLinePreprocessorStream(ObjectStream in) {
super(in);
}
private static boolean isLineEmpty(String line) {
return line.trim().length() == 0;
}
public String read() throws IOException {
String line = samples.read();
if (lastLineWasEmpty) {
lastLineWasEmpty = false;
while (line != null && isLineEmpty(line)) {
line = samples.read();
}
}
if (line != null && isLineEmpty(line)) {
lastLineWasEmpty = true;
line = "";
}
return line;
}
}