opennlp.tools.util.normalizer.TwitterCharSequenceNormalizer 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.util.normalizer;
import java.util.regex.Pattern;
/**
* A {@link TwitterCharSequenceNormalizer} implementation that normalizes text
* in terms of Twitter character patterns. Every encounter will be replaced by a whitespace.
*/
public class TwitterCharSequenceNormalizer implements CharSequenceNormalizer {
private static final long serialVersionUID = -8155452559337913929L;
private static final Pattern HASH_USER_REGEX =
Pattern.compile("[#@]\\S+");
private static final Pattern RT_REGEX =
Pattern.compile("\\b(rt[ :])+", Pattern.CASE_INSENSITIVE);
private static final Pattern FACE_REGEX =
Pattern.compile("[:;x]-?[()dop]", Pattern.CASE_INSENSITIVE);
private static final Pattern LAUGH_REGEX =
Pattern.compile("([hj])+([aieou])+(\\1+\\2+)+", Pattern.CASE_INSENSITIVE);
private static final TwitterCharSequenceNormalizer INSTANCE = new TwitterCharSequenceNormalizer();
public static TwitterCharSequenceNormalizer getInstance() {
return INSTANCE;
}
@Override
public CharSequence normalize (CharSequence text) {
String modified = HASH_USER_REGEX.matcher(text).replaceAll(" ");
modified = RT_REGEX.matcher(modified).replaceAll(" ");
modified = FACE_REGEX.matcher(modified).replaceAll(" ");
modified = LAUGH_REGEX.matcher(modified).replaceAll("$1$2$1$2");
return modified;
}
}