Manipulating configuration properties in spring

Question

I'm looking for a way to manipulate @ConfigurationProperties defined on initialization so that when I @Inject / @Autorwired the configured object using a @Bean method it is properly configured.

Scenario:

I have a bunch of properties set in a .yml file. Because all of these properties match as Strings some of them need special handling to be properly configured to their respective types (some of them are enums). Do I make my properties object a @Component then inject it into the @Bean method and modify it? I tried to combine @Bean and @ConfigurationProperties annotations but the object is configured AFTER the @Bean method itself returns, so any manipulation is lost/impossible. What is the best way to do this?

Example: In my .yml i have this:

properties:
  sports:
    "football": ["Team 1", "Team 2", "Team 3"]
    "basketball": ["Team 4", "Team 5", "Team 6"]
  settings:
    "football":
      "period1": "45"
      "period2": "90"
      "players": "11"
    "basketball":
      "periods": "4"
      "players": "5"

And these match with the following objects:

Map<SportsEnum, List<TeamsEnum>
Map<SportsEnum, Map<SportSettingsEnum, String>>

TL;DR: I want to take an object configured from a .yml/.properties file and manipulate its injectable representation. Please provide concrete example!

Answer 1

This is definitely supported, my guess is that you're doing something wrong. Let's go step by step.

First, your YAML file is badly formatted, it should look something like this:

properties:
  sports:
    football:
      - Team1
      - Team2
      - Team3
    basketball:
      - Team4
      - Team5
      - Team6
  settings:
    football:
      period1: 45
      period2: 90
      players: 11
    basketball:
      periods: 4
      players: 5

Then, your configuration properties would look like this:

@ConfigurationProperties(prefix = "properties", locations = "classpath:sports.yml")
public class SportsProperties {

    private Map<SportsEnum, List<TeamsEnum>> sports;
    private Map<SportsEnum, Map<SportSettingsEnum, String>> settings;

    public Map<SportsEnum, List<TeamsEnum>> getSports() {
        return sports;
    }

    public void setSports(Map<SportsEnum, List<TeamsEnum>> sports) {
        this.sports = sports;
    }

    public Map<SportsEnum, Map<SportSettingsEnum, String>> getSettings() {
        return settings;
    }

    public void setSettings(
        Map<SportsEnum, Map<SportSettingsEnum, String>> settings) {
        this.settings = settings;
    }

    @PostConstruct
    public void customManipulation() {
        System.out.println(sports);
        System.out.println(settings);
    }
}

Next, the properties should be enabled in your configuration:

@SpringBootApplication
@EnableConfigurationProperties(SportsProperties.class)
public class YamlSampleApplication {

    public static void main(String[] args) {
        SpringApplication.run(YamlSampleApplication.class, args);
    }

}

That should be it, really. Here are my enums:

public enum SportsEnum {
    football, basketball
}

public enum TeamsEnum {
    Team1, Team2, Team3, Team4, Team5, Team6
}

public enum SportSettingsEnum {
    periods, period1, period2, players
}

Here's the output I get in the logs:

2016-07-26 17:44:41.226 DEBUG 30015 --- [           main] s.b.e.YamlPropertySourceLoader$Processor : Loading from YAML: class path resource [sports.yml]
2016-07-26 17:44:41.282 DEBUG 30015 --- [           main] s.b.e.YamlPropertySourceLoader$Processor : Matched document with default matcher: {properties={sports={football=[Team1, Team2, Team3], basketball=[Team4, Team5, Team6]}, settings={football={period1=45, period2=90, players=11}, basketball={periods=4, players=5}}}}
2016-07-26 17:44:41.282 DEBUG 30015 --- [           main] s.b.e.YamlPropertySourceLoader$Processor : Loaded 1 document from YAML resource: class path resource [sports.yml]
{football=[Team1, Team2, Team3], basketball=[Team4, Team5, Team6]}
{football={period1=45, period2=90, players=11}, basketball={periods=4, players=5}}