Indexed mapping for arrays (e. g. Double[])

[Andy Schönemann]

I try to use indexed mapping together with arrays and get an ArrayStoreException at the following example. What's wrong here? When I replace Double[] with List<Double> all is working fine.

1) Bean:

import java.util.Arrays;

public class ArrayBean {

  Double[] array;
  public ArrayBean() {
    super();
  }

  public ArrayBean(Double[] array) {
    super();
    this.array = array;
  }

  public Double[] getArray() {
    return array;
  }

  public void setArray(Double[] array) {
    this.array = array;
  }

}

2) Main:

import org.supercsv.cellprocessor.ParseDouble;
import org.supercsv.cellprocessor.ift.CellProcessor;
import org.supercsv.io.dozer.CsvDozerBeanReader;
import org.supercsv.io.dozer.ICsvDozerBeanReader;
import org.supercsv.prefs.CsvPreference;

ublic class ArrayTest {

  private static final String[] FIELD_MAPPING = new String[] {
      "array[0]",
      "array[1]" };

  private static void readWithCsvDozerBeanReader() throws Exception {

    final CellProcessor[] processors = new CellProcessor[] {
        new ParseDouble(),
        new ParseDouble()
    };

    ICsvDozerBeanReader beanReader = null;
    try {
      beanReader =
          new CsvDozerBeanReader(new FileReader("src/test/resources/arrayTest.csv"),
              CsvPreference.STANDARD_PREFERENCE);

      beanReader.getHeader(true); // ignore the header
      beanReader.configureBeanMapping(ArrayBean.class, FIELD_MAPPING);

      ArrayBean arrayBean;
      while ((arrayBean = beanReader.read(ArrayBean.class, processors)) != null) {
        System.out.println(String.format("lineNo=%s, rowNo=%s, surveyResponse=%s", beanReader.getLineNumber(),
            beanReader.getRowNumber(), arrayBean));
      }

    } finally {
      if (beanReader != null) {
        beanReader.close();
      }
    }
  }

  public static void main(String[] args) throws Exception {
    readWithCsvDozerBeanReader();
  }

}

3) csv file:

"array[0]","array[1]"
1.0,2.0

[James Bassett]

Hi Andy,

Thanks for the comprehensive explanation - it makes it so much easier :)

This is a quirk with Dozer (see bug 39), where it needs a few hints to do the mapping.

You'll notice that beanReader.configureBeanMapping() is overloaded and one method accepts an array of hint types - this is passed to Dozer as a hint to the type of each column.

So you can simply set up the hints (both of your columns are Doubles):

private static final Class<?>[] HINT_TYPES = 
    new Class<?>[]{Double.class, Double.class};

And then pass those hints in when configuring the bean mapping:

beanReader.configureBeanMapping(ArrayBean.class, 
    FIELD_MAPPING, HINT_TYPES);

That should get you up and running again. Also, you probably don't want the bean mapping in the first row of your CSV file and in your code...