Overview

The platform provides the ability to initialize @Configured annotated fields and methods with configuration values from the XRuntime (alternative to using the XRuntime.getValue() API). Annotated fields and methods are discovered automatically for the main Talon application. Additional classes can be exposed using the @AppConfiguredAccessor annotation.

This article describes the usage of the configuration annotations:

Configuration Annotation Discovery

@Configured Annotation

The @Configured annotation is used to annotate application fields and methods to allow them to be discovered by a Talon Server. The Talon server will populate these fields and methods with settings given in Talon configuration.

The @Configured annotation supports following elements:

@AppIntrospectionPoints

Any @Configured annotated field or method in the main application class will be discovered by the Talon XVM. If additional classes in your application contain configured fields or methods, they can be exposed to the server using the @AppIntrospectionPoints annotation or @AppConfiguredAccessor annotation. The AppIntrospectionPoints annotation exposes a collection of application objects to introspect for any type of annotation supported by Talon while the AppConfiguredAccessor exposes a set of objects that should only be introspected for @Configured annotations. One can use the more narrowly scoped AppConfiguredAccessor annotation for applications that have a large number of objects to reduce the number of objects that the XVM needs to scan. 

Example:

    @AppHAPolicy(HAPolicy.EventSourcing)
    public static class MyApp {
        MyOtherClass someOtherClass = new MyOtherClass();

        @AppIntrospectionPoints 
        public void getApplicationObjects(Set<Object> object) {
            containers.add(someOtherClass );
        }
    }

    private static class MyOtherClass {
        @Configured(property = "simulator.ems.orderPreallocateCount", defaultValue = "1048576")
		private int orderPreallocateCount;
		MyOtherClass() {
        }
    }

@AppConfiguredAccessor

Any @Configured annotated field or method in the main application class will be discovered by the Talon server. If additional classes in your application contain configured fields or methods, they can be exposed to the server using the @AppConfiguredAccessor annotation.

Example:

    @AppHAPolicy(HAPolicy.EventSourcing)
    public static class MyApp {
        MyOtherClass someOtherClass = new MyOtherClass();

        @AppConfiguredAccessor
        public void getConfiguredContainers(Set<Object> containers) {
            containers.add(someOtherClass );
        }
    }

    private static class MyOtherClass {
        @Configured(property = "simulator.ems.orderPreallocateCount", defaultValue = "1048576")
		private int orderPreallocateCount;
		MyOtherClass() {
        }
    }

Configuration Discovery in Hornet

For Topic Oriented Applications, any @Managed object will be introspected for @Configured fields and methods. See ManagedObjectLocator. The DefaultManagedObjectLocator for TOA calls TopicOrientedApplication.addConfiguredContainers(Set), so unless your application provides its own managed object locator, additional configured containers can be added by overriding addConfiguredContainers():

    @AppHAPolicy(HAPolicy.EventSourcing)
    public static class MyApp extends TopicOrientedApplication {
        MyOtherClass someOtherClass = new MyOtherClass();

        @Override
        public void addConfiguredContainers(Set<Object> containers) {
            containers.add(someOtherClass );
        }
    }

    private static class MyOtherClass {
        @Configured(property = "simulator.ems.orderPreallocateCount", defaultValue = "1048576")
		private int orderPreallocateCount;
		MyOtherClass() {
        }
    }

Supported Configuration Types

Configuration values can be of the following types:

• boolean
• byte
• short
• int
• long
• float
• double
• char
• String or XString
• enumerations

When running in a Talon Server, it is possible to annotate @Configured fields:

import com.neeve.cli.annotations.Configured;
 
public class MyApp {

  @Configured(property = "simulator.ems.orderPreallocateCount", defaultValue = "1048576")
  private int orderPreallocateCount;
}

import com.neeve.cli.annotations.Configured;
 
public class MyApp {
  private int orderPreallocateCount;

  @Configured(property = "simulator.ems.orderPreallocateCount", defaultValue = "1048576")
  void setOrderPreallocateCount(int orderPreallocateCount) {
	this.orderPreallocateCount = orderPreallocateCount;
  }
}

Programmatic Access to Configuration

Configuration settings remain accessible via the XRuntime.getValue() API.