org.deeplearning4j.text.tokenization.tokenizer.NGramTokenizer Maven / Gradle / Ivy
/*-
*
* * Copyright 2015 Skymind,Inc.
* *
* * Licensed 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 org.deeplearning4j.text.tokenization.tokenizer;
import org.apache.commons.lang3.StringUtils;
import java.util.ArrayList;
import java.util.List;
/**
* @author sonali
*/
public class NGramTokenizer implements Tokenizer {
private List tokens;
private List originalTokens;
private int index;
private TokenPreProcess preProcess;
private Tokenizer tokenizer;
public NGramTokenizer(Tokenizer tokenizer, Integer minN, Integer maxN) {
this.tokens = new ArrayList<>();
while (tokenizer.hasMoreTokens()) {
String nextToken = tokenizer.nextToken();
this.tokens.add(nextToken);
}
if (maxN != 1) {
this.originalTokens = this.tokens;
this.tokens = new ArrayList<>();
Integer nOriginalTokens = this.originalTokens.size();
Integer min = Math.min(maxN + 1, nOriginalTokens + 1);
for (int i = minN; i < min; i++) {
for (int j = 0; j < nOriginalTokens - i + 1; j++) {
List originalTokensSlice = this.originalTokens.subList(j, j + i);
this.tokens.add(StringUtils.join(originalTokensSlice, " "));
}
}
}
}
@Override
public boolean hasMoreTokens() {
return index < tokens.size();
}
@Override
public int countTokens() {
return tokens.size();
}
@Override
public String nextToken() {
String ret = tokens.get(index);
index++;
return ret;
}
@Override
public List getTokens() {
List tokens = new ArrayList<>();
while (hasMoreTokens()) {
tokens.add(nextToken());
}
return tokens;
}
@Override
public void setTokenPreProcessor(TokenPreProcess tokenPreProcessor) {
this.preProcess = tokenPreProcessor;
}
}