实践中面向对象建模困难

class Client{
	public void sendFile(File file){
		CheckServer server=new CheckServer(this);
		server.check(file);
	}
	public void showState(String state){
		debug("state is :"+staste);
	}
}
class CheckServer{
	private Client client;
	CheckServer(Client client){
		this.client=client;
	}
	public void check(File file){
		//check file
		//fileName last with .rar
		client.showState("checking is ok");
		//use other task
		new RarServer(client).rar(file);
	}
}
class RarServer{
	private Client client;
	RarServer(Client client){
		this.client=client;
	}
	void rar(File file){
		//rar file
		client.showState("rarFile is ok");
	}
}
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