How to Bind Recursive Configuration Structures in Micronaut?

[alexey-lapin]

Hi!

I am wondering if it is possible to bind arbitrarily nested recursive structures in Micronaut.
In Spring it is possible to do so:

@SpringBootApplication
@EnableConfigurationProperties(AppConfig.class)
public class App {

    private AppConfig appConfig;

    public App(AppConfig appConfig) {
        this.appConfig = appConfig;
    }

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

}

@ConfigurationProperties("app")
public class AppConfig {

    private List<Condition> conditions;

    public List<Condition> getConditions() {
        return conditions;
    }

    public void setConditions(List<Condition> conditions) {
        this.conditions = conditions;
    }

}

public class Condition {

    private String type;
    private Condition not;
    private List<Condition> and;
    private List<Condition> or;

    public String getType() {
        return type;
    }

    public void setType(String type) {
        this.type = type;
    }

    public Condition getNot() {
        return not;
    }

    public void setNot(Condition not) {
        this.not = not;
    }

    public List<Condition> getAnd() {
        return and;
    }

    public void setAnd(List<Condition> and) {
        this.and = and;
    }

    public List<Condition> getOr() {
        return or;
    }

    public void setOr(List<Condition> or) {
        this.or = or;
    }
}

# application.properties
app.conditions[0].type=type1
app.conditions[1].and[0].type=type2
app.conditions[1].and[1].or[0].type=type3
app.conditions[1].and[1].or[1].type=type4

Is there an equivalent or alternative way to achieve this in Micronaut?

[dstepanov]

No, we calculate the properties path at the compilation time.

The only way would be using Micronaut Serialization and having the beans annotated with @Seardeable. Getting the map with PropertyResolver#getProperties then JsonMapper#writeValueToTree and JsonMapper#readValueFromTree Argument.listOf(Condition.class)

[TatyOko28]

Solution : Using @ConfigurationProperties with explicit nested classes

This works for simple recursive structures (one level of self-reference).

import io.micronaut.context.annotation.ConfigurationProperties;
import java.util.List;

@ConfigurationProperties("app")
public class AppConfig {
    private List<Condition> conditions;

    public List<Condition> getConditions() {
        return conditions;
    }

    public void setConditions(List<Condition> conditions) {
        this.conditions = conditions;
    }

    @ConfigurationProperties
    public static class Condition {
        private String type;
        private Condition not;      // Self-reference
        private List<Condition> and; // Self-reference in list
        private List<Condition> or;  // Self-reference in list

        public String getType() {
            return type;
        }

        public void setType(String type) {
            this.type = type;
        }

        public Condition getNot() {
            return not;
        }

        public void setNot(Condition not) {
            this.not = not;
        }

        public List<Condition> getAnd() {
            return and;
        }

        public void setAnd(List<Condition> and) {
            this.and = and;
        }

        public List<Condition> getOr() {
            return or;
        }

        public void setOr(List<Condition> or) {
            this.or = or;
        }
    }
}

application.yml:

app:
  conditions:
    - type: type1
    - and:
        - type: type2
        - or:
            - type: type3
            - type: type4