How to choose in runtime among several OSGi services in an intelligent way?

Question

I\'ve in mind an intelligent system which can choose among available OSGi services dynamically. That is, choose an implementation or another depending of some runtime parameter.

Answer 1

I guess, some sort of dynamic strategy pattern or even dependency injection could fit your needs. Some class uses a strategy (you called it operator) which can change at runtime. I think, you have another service that can tell the which strategy to use (based on runtime parameters).

A rough implementation could look like that:

public Worker {
  private Operator operator;    // your actual operator strategy
  public void setOperator(Operator actualOperator) {
    this.operator = operator;
  }

  public doSomething() {

     while(stopCriterion) {
       Operator operatorForThisIteration = operator;  // pick the injected service
       operatorForThisIteration.doSomething;
     }
  }
}

And another service, the one that can inject dependencies to worker instances, would maintain a list of all worker instances, implement some logic to choose a new service and inject in into all (or some) workers.