flink-ml-examples/src/main/java/org/apache/flink/ml/examples/feature/TokenizerExample.java

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 * 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
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package org.apache.flink.ml.examples.feature;

import org.apache.flink.ml.feature.tokenizer.Tokenizer;
import org.apache.flink.streaming.api.datastream.DataStream;
import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
import org.apache.flink.table.api.Table;
import org.apache.flink.table.api.bridge.java.StreamTableEnvironment;
import org.apache.flink.types.Row;
import org.apache.flink.util.CloseableIterator;

import java.util.Arrays;

/** Simple program that creates a Tokenizer instance and uses it for feature engineering. */
public class TokenizerExample {
    public static void main(String[] args) {
        StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
        StreamTableEnvironment tEnv = StreamTableEnvironment.create(env);

        // Generates input data.
        DataStream<Row> inputStream =
                env.fromElements(Row.of("Test for tokenization."), Row.of("Te,st. punct"));
        Table inputTable = tEnv.fromDataStream(inputStream).as("input");

        // Creates a Tokenizer object and initializes its parameters.
        Tokenizer tokenizer = new Tokenizer().setInputCol("input").setOutputCol("output");

        // Uses the Tokenizer object for feature transformations.
        Table outputTable = tokenizer.transform(inputTable)[0];

        // Extracts and displays the results.
        for (CloseableIterator<Row> it = outputTable.execute().collect(); it.hasNext(); ) {
            Row row = it.next();

            String inputValue = (String) row.getField(tokenizer.getInputCol());
            String[] outputValues = (String[]) row.getField(tokenizer.getOutputCol());

            System.out.printf(
                    "Input Value: %s \tOutput Values: %s\n",
                    inputValue, Arrays.toString(outputValues));
        }
    }
}