title: Why The value for annotation attribute Rest.rootUrl must be a constant expression?
body: <p>Im using <a href="https://github.com/excilys/androidannotations" rel="nofollow">Android Annotations Framework</a>, specially for Rest Integration. 
  I have the following code.</p>
  
  <p>An interface for Host configuration</p>
  
  <pre><code>public interface Host {
      public String URL = "http://192.168.2.137";
  }
  </code></pre>
  
  <p>And the annotated Interface for Rest communication.</p>
  
  <pre><code>@Rest(rootUrl = Host.URL, converters = { MappingJacksonHttpMessageConverter.class })
  public interface RestClient {
      @Get("/entities.json")
      Entity[] allEntities();
  }
  </code></pre>
  
  <p>and my question is, <strong>Why the value for annotation attribute Rest.rootUrl must be a constant expression? and how can i use a String resource for Rest.rootUrl ?</strong></p>
  
  <p>I wish to do something like</p>
  
  <pre><code>@EBean
  public class Host{
      @StringRes
      String URL;
  }
  </code></pre>
  
  <p>But is impossible with the RestClient interface.</p>
  
  <p>The idea is to handle a localized rest application, suppose distinct URLs by language </p>
  
  <pre><code>http://en.myapp.com
  http://es.myapp.com
  </code></pre>
  
  <p>I know that an Java Interface must have final properties, but, there are a way to handle a localized rootUrl value?</p>
  
  <p>Thanks.</p>