src/main/java/org/apache/sysds/runtime/transform/tokenize/builder/TokenizerBuilderWhitespaceSplit.java

/*
 * 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.
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package org.apache.sysds.runtime.transform.tokenize.builder;

import org.apache.sysds.runtime.frame.data.FrameBlock;
import org.apache.sysds.runtime.transform.tokenize.DocumentRepresentation;
import org.apache.sysds.runtime.transform.tokenize.Token;
import org.apache.wink.json4j.JSONException;
import org.apache.wink.json4j.JSONObject;

import java.util.ArrayList;
import java.util.List;
import java.util.Objects;

import static org.apache.sysds.runtime.util.UtilFunctions.getEndIndex;

public class TokenizerBuilderWhitespaceSplit extends TokenizerBuilder {

	private static final long serialVersionUID = 539127244034913364L;

	private final int[] idCols;
	private final int tokenizeCol;

	public String regex = "\\s+"; // whitespace

	public TokenizerBuilderWhitespaceSplit(int[] idCols, int tokenizeCol, JSONObject params) throws JSONException {
		if (params != null && params.has("regex")) {
			this.regex = params.getString("regex");
		}
		this.idCols = idCols;
		this.tokenizeCol = tokenizeCol;
	}

	public List<Token> splitToTokens(String text) {
		List<Token> tokenList = new ArrayList<>();
		if(text == null)
			return tokenList;
		String[] textTokens = text.split(this.regex);
		int curIndex = 0;
		for(String textToken: textTokens) {
			if(Objects.equals(textToken, "")){
				continue;
			}
			int tokenIndex = text.indexOf(textToken, curIndex);
			curIndex = tokenIndex;
			tokenList.add(new Token(textToken, tokenIndex));
		}
		return tokenList;
	}

	@Override
	public void createInternalRepresentation(FrameBlock in, DocumentRepresentation[] internalRepresentation, int rowStart, int blk) {
		int endIndex = getEndIndex(in.getNumRows(), rowStart, blk);
		for (int i = rowStart; i < endIndex; i++) {
			String text = in.getString(i, tokenizeCol - 1);
			List<Token> tokenList = splitToTokens(text);
			List<Object> keys = new ArrayList<>();
			for (Integer idCol : idCols) {
				Object key = in.get(i, idCol - 1);
				keys.add(key);
				internalRepresentation[i] = new DocumentRepresentation(keys, tokenList);
			}
		}
	}
}