逻辑问题 - GWT

Question

我试着去测试的性能技巧：https://groups.google.com/forum/#!msg/google-web-toolkit/f9FLCEloW-c/3ZelaqGUGTcJ

我有不同的结果对象超过5个不同的回调。

我怎么能创造只在一个静态类动态静态类：

public class AsyncCallbacks 
{ 
    private static AsyncCallback<?> callback = null; 


    private AsyncCallbacks(){ 

    } 


    private AsyncCallback<?> createCallback() { 
      if(callback == null) { 

       callback = new AsyncCallback(){ 

       @Override 
       public void onFailure(Throwable caught) 
       { 
        // TODO Auto-generated method stub 

       } 

       @Override 
       public void onSuccess(Object result) 
       { 
        // TODO Auto-generated method stub 

       } 

       }; 



      } 
      return callback; 
     } 






} 

Answer 1

public class Asyncs implements AsyncCallback<Object> { 

    private Dto1 dto1 = null; 
    private Dto2 dto2 = null; 

    private Object result = null; 

    @Override 
    public void onFailure(Throwable caught) { 
    // failed message 
    } 

    @Override 
    public void onSuccess(Object result) { 
    this.result = result; 
    } 

    public Object getSuccessObject() { 
    if (result instanceof Dto1) { 
     dto1 = (Dto1) result; 
    } else if (result instanceof Dto2) { 
     dto2 = (Dto2) result; 
    } 
    return result; 
    } 

}