Paths.java

class Post {
  
  Long id;
  String title;
  
  Post(Long id, String title) {
    this.id = id;
    this.title = title;
  }
  
}

class Comment {
  Long id;
  String body;
}

class Activity  {

  Pipeline pipeline = new Pipeline(BLOG_SERVER_URL);
  Post parent = new Post(1, "Ex Post");

  void onCreate() {
    PipeConfig commentsConfig = new PipeConfig(Comment.class);
    commentsConfig.setParentPath("/post/${id}/");
    
    pipeline.pipe(Comment.class, commentsConfig);
    
  }
  
  void onStart() {
    
    /**
     * read(id, parent, callback) will look at the parent path,
     * extract property keys (${id}) and then try to load those values
     * from the parent object.  (parentPost.id)
     */
    pipeline.get("comment", this).read(1, parentPost, new ActivityCallback());
    
  }

}