Creating a StreamSets Spark Transformer in Java - after first code expansion

CustomTransformer.java

package com.streamsets.spark;

import com.streamsets.pipeline.api.Record;
import com.streamsets.pipeline.spark.api.SparkTransformer;
import com.streamsets.pipeline.spark.api.TransformResult;
import org.apache.spark.api.java.JavaPairRDD;
import org.apache.spark.api.java.JavaRDD;
import org.apache.spark.api.java.JavaSparkContext;
import org.apache.spark.api.java.function.Function;
import scala.Tuple2;

import java.io.Serializable;
import java.util.List;

import com.streamsets.pipeline.api.Field;
import java.util.HashMap;
import java.util.Map;

public class CustomTransformer extends SparkTransformer implements Serializable {
  private static final String VALUE_PATH = "/credit_card";
  private static final String RESULT_PATH = "/credit_card_type";
  private static HashMap<String, String[]> ccTypes;
  static {
    // Create a map of card type to list of prefixes
    ccTypes = new HashMap<>();
    ccTypes.put("Visa", new String[]{"4"});
    ccTypes.put("Mastercard", new String[]{"51","52","53","54","55"});
    ccTypes.put("AMEX", new String[]{"34","37"});
    ccTypes.put("Diners Club", new String[]{"300","301","302","303","304","305","36","38"});
    ccTypes.put("Discover", new String[]{"6011","65"});
    ccTypes.put("JCB", new String[]{"2131","1800","35"});
    ccTypes.put("Other", new String[]{""});
  }
  private transient JavaSparkContext javaSparkContext;

  @Override
  public void init(JavaSparkContext javaSparkContext, List<String> params) {
    this.javaSparkContext = javaSparkContext;
  }

  @Override
  public TransformResult transform(JavaRDD<Record> records) {
    // Create an empty errors JavaPairRDD
    JavaRDD<Tuple2<Record,String>> emptyRDD = javaSparkContext.emptyRDD();
    JavaPairRDD<Record, String> errors = JavaPairRDD.fromJavaRDD(emptyRDD);

    // Apply a map to the incoming records
    JavaRDD<Record> result = records.map(new Function<Record, Record>() {
      public Record call(Record record) throws Exception {
        // Get the credit card number from the record
        String creditCard = record.get(VALUE_PATH).getValueAsString();

        // Look through the map of credit card types
        for (Map.Entry<String, String[]> entry : ccTypes.entrySet()) {
          // Find the first matching prefix
          for (String prefix : entry.getValue()) {
            if (creditCard.startsWith(prefix)) {
              // Set the credit card type
              record.set(RESULT_PATH, Field.create(entry.getKey()));
              return record;
            }
          }
        }

        return record;
      }
    });
    return new TransformResult(result, errors);
  }
}