opennlp.tools.util.normalizer.ShrinkCharSequenceNormalizer 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;
/**
* Normalizer to shrink repeated spaces / chars
*/
public class ShrinkCharSequenceNormalizer implements CharSequenceNormalizer {
private static final Pattern REPEATED_CHAR_REGEX = Pattern.compile("(.)\\1{2,}",
Pattern.CASE_INSENSITIVE);
private static final Pattern SPACE_REGEX = Pattern.compile("\\s{2,}",
Pattern.CASE_INSENSITIVE);
private static final ShrinkCharSequenceNormalizer INSTANCE = new ShrinkCharSequenceNormalizer();
public static ShrinkCharSequenceNormalizer getInstance() {
return INSTANCE;
}
public CharSequence normalize (CharSequence text) {
text = SPACE_REGEX.matcher(text).replaceAll(" ");
return REPEATED_CHAR_REGEX.matcher(text).replaceAll("$1$1").trim();
}
}