Defining a Top-Level Object Type in Interface Style

Defining a top-level object type is a special case of defining a singleton type, with two differences: First, a top-level object type does not require a getConcept method, because its concept is self-evident (it is always TeaConcept.TOP_LEVEL). Second, TopLevelTeaObject extends the WithMembers interface, so you must implement the getMemebers method.

Procedure

Define a class that models the managed object type. Your class must implement the interface TopLevelTeaObject. For example, when modeling a car, the top-level is the car itself.

public class Car implements TopLevelTeaObject {

    public String getName() {
        // Return the name of the car instance;
        return "Car";
    }

    public String getDescription() {
        // Return the description of the car instance;
        return "Car";
    }

    public String getKey() {
        // Return the key that corresponds to the car instance;
        return "Car";
    }

      // These methods give the top-level object functionality 
     // that would otherwise be in the provider.

    public String getTypeName() {
        // Return the name of the car object type.
        return "Car";
    }

    public String getTypeDescription() {
        // Return the description of the car object type.
        return "Car";
    }

    public Collection<BaseTeaObject> getMembers() {
        	// Return the main parts of the car.
    }

}

Register the unique instance of the class.
```
CarAgentServer server = ...
Car myCar = new Car;
server.registerInstance(myCar);
// Register other instances.
 ...
server.start();
```
Notice that instead of registering the provider, we register the unique instance of the car class.