opennlp.tools.util.featuregen.TokenClassFeatureGenerator 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.featuregen;
import java.util.List;
import opennlp.tools.util.StringUtil;
/**
* Generates features for different for the class of the token.
*/
public class TokenClassFeatureGenerator implements AdaptiveFeatureGenerator {
private static final String TOKEN_CLASS_PREFIX = "wc";
private static final String TOKEN_AND_CLASS_PREFIX = "w&c";
private boolean generateWordAndClassFeature;
public TokenClassFeatureGenerator() {
this(false);
}
public TokenClassFeatureGenerator(boolean generateWordAndClassFeature) {
this.generateWordAndClassFeature = generateWordAndClassFeature;
}
public void createFeatures(List features, String[] tokens, int index, String[] preds) {
String wordClass = FeatureGeneratorUtil.tokenFeature(tokens[index]);
features.add(TOKEN_CLASS_PREFIX + "=" + wordClass);
if (generateWordAndClassFeature) {
features.add(TOKEN_AND_CLASS_PREFIX + "=" + StringUtil.toLowerCase(tokens[index]) +
"," + wordClass);
}
}
}