java - 我如何避免这种忙等待？

Question

public int getChildrenCount(int groupPosition) {
    if(children == null){
        new SalesRequest().execute(); // runs in other thread which 
                                      // initialises children with some value.
        while(children == null){
            // I'm doin this to avoid null pointer Exception.
            // So it comes out of the loop only when childern 
            // gets initialised.
        }
    }
    return children.length;
}

但我对自己处理此事的方式不满意。有更好的方法吗？

Answer 1

您可以使用 CountDownLatch 来等待其他线程完成。

http://download.oracle.com/javase/1,5.0/docs/api/java/util/concurrent/CountDownLatch.html