又一個Java事件問題

Question

所以我看到了多個關於stackoverflow的問題，詢問如何在java中實現事件，但沒有一個似乎提供了其他示例，然後「閱讀本」。

是否有人可以提供一個簡潔的例子來說明如何實現下面的C＃代碼的基本等價物？

public event EventHandler<MessageReceivedEventArgs> MessageReceived; 
protected virtual void OnMessageReceived(Socket socket, CommandType commandType, MemoryStream message) 
{ 
    if (this.MessageReceived != null) 
    { 
     this.MessageReceived(this, new MessageReceivedEventArgs(socket, commandType, message)); 
    } 
} 

Answer 1

通常在Java中不使用多播代理。如果你不需要多件，那麼代碼會是這樣：

public interface MessageReceivedListener { 
    void onMessageReceived(Object sender, MessageReceivedEventArgs e); 
} 

private MessageReceivedListener messageReceivedListener; 

public void setMessageReceivedListener(MessageReceivedListener listener) { 
    this.messageReceivedListener = listener; 
} 

protected void onMessageReceived(Socket socket, CommandType commandType, MemoryStream message) { 
    if (this.messageReceivedListener != null) { 
     this.messageReceivedListener.onMessageReceived(this, 
      new MessageReceivedEventArgs(socket, commandType, message)); 
    } 
} 

如果你想實現多播，那麼你就可以創建一個聽衆容器，通過這些聽衆迭代，並調用處理程序。在這種情況下，將會有addMessageReceivedListener和removeMessageReceivedListener管理活動偵聽器的方法。