Java: Owner: type conversion for arrays, collections

In my previous posts, I explained how Owner API maps a property to Custom object, primitive types. In addition to these, Owner API also provides support for Arrays and Collections.

import java.util.List;

import org.aeonbits.owner.Config;

public interface ProjectConfig extends Config {

  @DefaultValue("Saturday, Sunday")
  String[] days();

  @DefaultValue("January, February, March, April")
  String[] month();

  @DefaultValue("1988, 1989")
  List<Integer> year();

}

import org.aeonbits.owner.ConfigFactory;
import java.util.*;

public class PropertyUtil {
  public static void main(String args[]) throws Exception {
    Map<String, String> properties1 = new HashMap<>();

    properties1.put("days", "Tuesday, Wednesday, Thrusday, Friday");
    properties1.put("month", "October, November, December");

    ProjectConfig cfg = ConfigFactory.create(ProjectConfig.class,
        properties1);

    String[] days = cfg.days();
    String[] months = cfg.month();
    List<Integer> years = cfg.year();

    System.out.println("----------------------");
    for (String day : days) {
      System.out.println(day);
    }

    System.out.println("----------------------");
    for (String month : months) {
      System.out.println(month);
    }

    System.out.println("----------------------");
    for (int year : years) {
      System.out.println(year);
    }
  }
}

Output

----------------------
Tuesday
Wednesday
Thrusday
Friday
----------------------
October
November
December
----------------------
1988
1989

@DefaultValue("January, February, March, April")

As you see, by default elements in array (or) collection are separated by ,.

You can change this default separator to any string.

For example,

@Separator(";")

@DefaultValue("January; February; March; April")

String[] month();

Above snippet uses ; as separator value.

import java.util.List;

import org.aeonbits.owner.Config;

public interface ProjectConfig extends Config {

  @Separator("_")
  @DefaultValue("Saturday$Sunday")
  String[] days();

  @Separator(";")
  @DefaultValue("January; February; March; April")
  String[] month();

  @Separator("-")
  @DefaultValue("1988-1989")
  List<Integer> year();

}

import org.aeonbits.owner.ConfigFactory;
import java.util.*;

public class PropertyUtil {
  public static void main(String args[]) throws Exception {
    Map<String, String> properties1 = new HashMap<>();

    properties1.put("days", "Tuesday_ Wednesday_ Thrusday_ Friday");
    properties1.put("month", "October; November; December");

    ProjectConfig cfg = ConfigFactory.create(ProjectConfig.class,
        properties1);

    String[] days = cfg.days();
    String[] months = cfg.month();
    List<Integer> years = cfg.year();

    System.out.println("----------------------");
    for (String day : days) {
      System.out.println(day);
    }

    System.out.println("----------------------");
    for (String month : months) {
      System.out.println(month);
    }

    System.out.println("----------------------");
    for (int year : years) {
      System.out.println(year);
    }
  }
}

Output

----------------------
Tuesday
Wednesday
Thrusday
Friday
----------------------
October
November
December
----------------------
1988
1989

Just like how you specify @Separator annotation on method level, you can also specify it on class level.

import java.util.List;

import org.aeonbits.owner.Config;
import org.aeonbits.owner.Config.Separator;

@Separator(";")
public interface ProjectConfig extends Config {

  @DefaultValue("Saturday;Sunday")
  String[] days();

  @DefaultValue("January; February; March; April")
  String[] month();

  @Separator("_")
  @DefaultValue("1988_1989")
  List<Integer> year();

}

import org.aeonbits.owner.ConfigFactory;
import java.util.*;

public class PropertyUtil {
  public static void main(String args[]) throws Exception {
    Map<String, String> properties1 = new HashMap<>();

    properties1.put("days", "Tuesday; Wednesday; Thrusday; Friday");
    properties1.put("month", "October; November; December");

    ProjectConfig cfg = ConfigFactory.create(ProjectConfig.class,
        properties1);

    String[] days = cfg.days();
    String[] months = cfg.month();
    List<Integer> years = cfg.year();

    System.out.println("----------------------");
    for (String day : days) {
      System.out.println(day);
    }

    System.out.println("----------------------");
    for (String month : months) {
      System.out.println(month);
    }

    System.out.println("----------------------");
    for (int year : years) {
      System.out.println(year);
    }
  }
}

Output

----------------------
Tuesday
Wednesday
Thrusday
Friday
----------------------
October
November
December
----------------------
1988
1989

Note

The Map interface and sub-interfaces are not supported.

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