BeanIO - Collection of abstract class or class implementing interface

Question

Is it possible, using the BeanIO annotations, to define a field as a collection of an abstract class, or a collection of classes implementing an interface?

What I want is this:

@Record(minOccurs = 1, maxOccurs = -1, collection = List.class)
List<SomeInterface> records;

I then supply a list of different concrete classes to the collection, which all contains all the annotations for defining a valid record.

However I just get an error saying

Repeating segments without any child field component must have minOccurs=maxOccurs

...which kind of defeats the purpose.

Some things I have tried:

Setting the stream to writeOnly
Using an abstract class instead of an interface

EDIT: This is my configuration:

  StreamFactory factory = StreamFactory.newInstance();
  StreamBuilder builder = new StreamBuilder("MyStreamName")
                .writeOnly()
                .format("delimited")
                .parser(new DelimitedParserBuilder(','))
                .addGroup(Parent.class);
  factory.define(builder);

...whereas the Parent.class contains the List<SomeInterface> records;

Logically, there should be something tying the SomeInterface to the concrete implementations of the interface so that BeanIO could figure out what to do, but I can't seem to figure out how to set up this connection.

Does this help? https://groups.google.com/g/beanio/c/DAcA7t33zvk — nicoschl, Jul 12 '20 at 22:58

nicoschl · Accepted Answer · 2020-07-15T23:46:29.520

The following is working for me:

import org.beanio.annotation.Record;

@Record(name = "parentRecord", maxOccurs = 1, minOccurs = 1, collection = List.class)
public class Parent {

  @Record(minOccurs = 1, collection = List.class, name = "recordList")
  private List<A> records;

  // getter + setter
}

The Parent class is now a @Record which need a change in the StreamBuilder to

final StreamFactory factory = StreamFactory.newInstance();
final StreamBuilder builder = new StreamBuilder("MyStreamName")
  .writeOnly()
  .format("delimited")
  .parser(new DelimitedParserBuilder(','))
  .addRecord(Parent.class);
factory.define(builder);

This runs for me without any exceptions

BeanIO - Collection of abstract class or class implementing interface

1 Answers1